Don’t attempt any of the finish welding until all the hull plating is tack-welded into position. Before you start the final welding, give your hull a final check for irregularities. They will be easier to correct before the welding is completed. Bumps can be removed by any one of several metalworking techniques, including using a rubber mallet on one side while a helper holds a suitably shaped timber backing-piece on the other. Hollows on the hull are most unsightly, and must be removed. Small wrinkles along the chine can be removed from inside with the careful use of a large plastic-faced mallet and a person holding a suitable backing-piece from outside the hull.

Final welding consists of short welds laid down in the proper sequence for that particular plating. As mentioned in Chapter 5, Welding, different techniques are required to weld steel, aluminum, and copper-nickel. You must be fully conversant with the method best suited to the plating of your hull.

   Much of the work, up until the running of the finish welds, can be handled by a person with a minimum of welding experience, but the final welding of the plating is another matter. If you’re not a fully experienced welder, this may be the time to hire a professional. If you plan to take this route, we recommend that you seek help before you start the project. Discuss with the professional how much you can do yourself, and when and where you will need his or her assistance.

   If you’re going to seek outside assistance, make sure the person understands the problems of welding a pleasure boat. Welding a boat is quite different to commercial welding. In commercial welding, strength is important but laying down a considerable amount of weld per hour also has a high priority. A commercial welder might not consider a fine finish to be so important. Explain your expectations to the professional before you enter into a firm agreement. If you find that the person you’ve chosen doesn’t come up to your expectations, make other arrangements before the job gets out of hand.

   When the welding of the plating is completed, you’ll need to grind off some of your welds from the outside of the hull. If you have laid good-quality welds with good penetration, you’ll have the minimum of chipping and grinding before repairing or re-welding any unsatisfactory joins in the plate. It’s normal practice to grind only those welds above the waterline. Most classification societies insist that the welds below the waterline are left ungrounded so they retain all the strength of the original weld. Do not over-grind the welded seams above the waterline, otherwise you may weaken them to such an extent that you compromise the strength of the vessel.

Keel Plating

   If you’ve built your hull upside down, now will be the time to plate the keel. The keel’s leading edge (usually pipe or split pipe), the webs, and the aft end of the keel will already be in place. Your plans will instruct you about the order in which to plate the sides and the bottom. In the past, we’ve usually specified 1/4-inch (6 mm) material for the sides, and 1/2-inch (12 mm) for the bottom plate. Today, we’d be happy to have the whole structure built of 1/4-inch (6 mm) plate; this means that at the intersections of the sides and the bottom, you’ll be welding material of the same thickness. Also, in the case of boats built inverted, you’ll not have to struggle with the heavier 1/2-inch (12 mm) plate at the bottom of the keel.

If you’re lucky, your plans will include an expanded pattern for the transom. If you don’t have this pattern, it’s a simple matter to make up some transom formers to the correct camber and then, using inexpensive plywood or hardboard, simply make up a pattern to fill in the transom cavity. Make sure you don’t create a “fish-tail” effect at the aft end of your hull. This is caused by making the transom too large (usually, too wide), and preventing the side and bottom plating from taking up its fair line. Don’t forget to allow for the deck or transom camber when you’re making the pattern and cutting the plate for the transom.

   Once you’re convinced that the transom plate is the right size and shape, you can install it. It’s usual to have a centreline bar extending from the bottom of the hull to the top of the transom, and you can hang the transom plate on this bar while you’re positioning the plate. The remainder of the transom stiffeners, usually vertical and transverse stringers, can be installed from inside once the transom plate is fully welded from the outside.

RUBRAILS

You can make rub-rails, rubbing strips, or rubbing strakes from the same metal as the hull, or from one of a variety of other materials. The selection includes, but is not restricted to, D-section rubber mounted on a suitable metal structure; timber bolted in place; and rope mounted in a channel or other similar arrangement.

   If you’re using timber for the rub-rail, it should be hardwood. Timbers similar to teak, or softer timbers, can be satisfactory when fitted with a stainless protective strip. For the ultimate timber rubbing strake, Australian spotted gum has the advantage of being durable, flexible, and long-lasting without the need for any additional metal protective strip. In general, timber is easily replaced, can be attractive, and is kind to other boats and structures.

   A metal half-round split pipe of suitable dimensions makes an ideal rub rail on a metal boat. We show it on all our metal sailboat designs. You simply take the correct length of pipe, split it lengthwise, and use one half for each side. The aft end can be snaped and plugged with an appropriately shaped piece of hull material. It will finish either at the transom or about 6 inches (150 mm) ahead of it. The other end is tapered so that it will bend around the forward end of the hull, usually ending at or about station 0, or above the forward end of the waterline. Make sure that you give extra preparation and coating to the inside of the pipe and the hull where it will be installed. Placing underneath the rub-rail a thicker hull plate that is 50 percent wider overall than the rubbing strip would provide extra insurance against corrosion and damage from contact with immovable objects.

   The problem with this pipe rub-rail is that you cannot repaint the inside. Even if you’re very careful to give the inside a superior paint job before it’s installed, the welding will undo at least part of your work. The pipe itself will have sufficient wall thickness to withstand many years of interior corrosion, but the plating underneath may not be so long-lasting. One solution would be to have a thicker base plate under the pipe, say three times wider than the pipe. It should be inserted into the hull plating, but not over the regular hull plating or you could have problems between the two plates. Skegs and other appendages are covered in Chapter 15. If there is a skeg involved in your hull design, you may prefer to install it after the turnover operation.

If you’ve built your hull upside down, now is the time to consider the turnover. When the plating is completed and all of the final outer welds have been run, you can decide on the best method for turning your hull and setting it in the upright position. No matter if yours is a large or small hull, give considerable thought to safety factors when considering how you will turn it over. Plan how to set up the hull and level it, ready for completion. The last thing you need at this stage is an injury to yourself, a friend, or hired assistant, so take care.

   Several methods have been used successfully to turn over large boat hulls. The method you choose will be in some part decided by the size of your boat, its location, and the accessibility of your building site. Boats up to about 25 feet (7.62 m) long can be rolled over without the use of mechanical assistance. For small hulls, you’ll need no more than a few willing friends and a few bottles of cheer.

   If you’re building in a large, substantial commercial building then you may have overhead track fitted with chain blocks. It may be possible to set up strong points in the building that are capable of taking the load. You can arrange two overhead chain blocks for two endless slings capable of lifting the hull. Now the structure can be rolled over in its own width. The two slings are placed about 20 percent in from each end of the hull. You will need restraining lines to control the hull during the turning-over operation.

It may be preferable to remove the hull from the building and turn it over outside where there’s more room. Or you may already have built hoops around your hull so that it can simply be rolled over. The hoops will later be used to tilt the hull to various angles, thus allowing easier access to the job at all times. Or you may wish to build a “turnover cradle,” shaped something like a crate, around your hull and turn it over one side at a time.

   Our choice would be to hire a crane fitted with a spreader bar and two endless slings. The slings are placed in about 20 percent from the bow and stern and the crane lifts the hull sufficiently to allow it to be rotated in the slings. Make sure you determine the balance fore and aft before the serious lifting begins. You will need restraining lines attached to a winch or other suitably strong device, to control the hull as it reaches the up and over stages.

   When you have turned the hull, you’ll need to set it up level in all directions. Use the waterline locations that you have previously marked on the outside of the hull as a guide. The simple type of water level with a clear tube will make it easy for you to set up the hull true and level in all planes.

Moving the Hull

   You can move large, bulky, and heavy items such as boat hulls using the simplest of tools. You can use a few 2-inch (50 mm) diameter pipe rollers about 9 inches (230 mm) long to roll your hull. Simply lay down planks for the rollers to run on, and keep taking the rollers from the back and reinstalling them at the front as the hull moves along the desired path. If you use either 4 by 2 inch (100 by 50 mm) timber, or 2-inch (50 mm) pipe levers, say 5 feet (1.50 m) long, you’ll multiply your strength many times when it comes to lifting or shifting heavy weights. When you’re lifting the hull or frame to insert the rollers, you’ll find the levers are much quicker to use than a lifting jack.

You’ll want to give some thought to the sequence of the various steps needed to finish the deck and superstructure. The building sequence includes grit blasting, insulating the hull, and may include installing the engine and fitting out the interior. You may want to undertake some of these steps before you build the decks and superstructure, so you’ll need to plan your own work schedule. You must also be prepared to make minor changes as you proceed with the work. You may be considering building the decks, and/or the superstructure, in a different material from that of the hull (usually not recommended by this designer). As most of you will be building the entire boat in one metal, however, we’ll leave detailed discussion on alternative deck and superstructure materials until nearer the end of this chapter.

   Before you start to build the decks and superstructure, you should consider installing all the bulky items that will need to be in the hull and which may be difficult, if not impossible, to install after the deck and cabin are in place. The engine, large tanks, bulkhead panels, the plywood sole and similar items need to be in position before the hull is closed up by addition of the superstructure. You will have to balance this against the fact that you may need to grit-blast the inside of the decks and superstructure, a practice that would not be recommended around your new engine! Again this is another reason why we recommend using all pre-grit-blasted and pre-prime-coated steel.

   If your hull is large enough, say over 35 feet (10.67 m), you may plan to set up a small workshop inside the hull where you can manufacture much of the joinery. This is worthwhile if you can fit in a small bench, a table saw, and a band saw, otherwise it may be better to consider one of the alternatives. For example, if your boat is smaller, or if you prefer to work outside the hull, then consider setting up a work area at the sheer or deck level, then you’ll only have to climb a few steps to saw, plane, rout, sand, or temporarily assemble a piece of joinery. This can save a great deal of time and effort. Getting up and over and out of the boat to make each cut can soon become very tiring (and tiresome), so a better plan is needed.

   You may find that some of the cabinets and joinery can be set up inside the hull and then taken out to a nearby bench for sanding, painting, and so forth, before being reinstalled in the hull. It’s better to undertake as much preparation as possible before the deck goes on.

This brings us to the grit-blasting that’s necessary in steel boats. When is the best time to undertake this work? In our opinion, the best time is before the boat is started—yes, this means pre-grit-blasting and priming all of the materials. If you opt to work with untreated steel, you’ll have some problems with working out the sequence of fitting out. You can’t install the insulation, the engine, or other large items until after you’ve grit-blasted and primed the inside of the hull. You certainly cannot grit blast the interior once these items are in place. You can see that if you work with untreated steel, you may create scheduling difficulties. Builders who choose steel as their building material should avoid these problems by either purchasing the steel already pre-blasted and primed, or by doing the job themselves before they start construction

Your plans and patterns may include either the measurements or an actual full-size pattern for the deck and cabin top cambers. Using this pattern, it’s a simple matter to cut a hard pattern from plywood or suitable timber. If you get the balance right, you can cut a male and female pattern from one plank. The pattern will be used to obtain the correct camber when you’re bending the deck beams and cabin beams.

   On sailboats, the cabin and the pilothouse tops will usually have more camber than the decks.. On powerboats, the opposite is sometimes the case, although quite often the same camber is used throughout. If your plans don’t include full-size camber patterns, you can create patterns using the designer’s recommended cambers, as shown below. For instance, in a powerboat that will be fitted with a flybridge, it is best to have a minimum (but still some) of camber in the cabin or pilothouse top as this will form the sole of your flybridge and too much camber is not desirable.

Bulkheads

   If you’re building upright, you may have included some of the bulkheads as you were setting up the initial frames. It would also be possible to include bulkheads when you’re setting up an inverted hull, but it may involve raising the whole structure so far off the floor that it would be impractical. Any setting-up method that makes you climb or walk more than is absolutely necessary is not recommended. In cases where the hull is built upside down, my preference is to wait until the hull is plated and upright before considering the installation of any bulkheads. That gives you an overview of the hull, so you can take stock of the available space before making firm decisions about placing bulkheads that will affect the layout of the accommodation.

   You’ll need to decide which bulkheads will be metal and which will be plywood. The bulkheads that will be exposed to the elements should all be metal, including the aft bulkhead of the cabin and the bulkhead located at forward end of the aft cabin. If you have a pilothouse, the aft bulkhead should be metal. In Dutch powerboats, the aft end of the saloon or pilothouse is sometimes made partially of timber. This is acceptable if there is some awning or shelter over it to protect it from the elements. Bulkheads will usually be constructed from the same metal used for the decks. In boats under 40 feet (12.19 m), try to keep the number of metal bulkheads to a minimum, and use plywood where practical.

METAL BULKHEADS

The bulkheads at the forward and aft ends of the engine room in both sailboats and powerboats should be constructed from the same metal as the decks but in some cases may be one measurement smaller in thickness. For instance where the decks are 3/16 inch (5 mm) you may use 5/32 inch (4 mm) steel for the bulkhead plate.

As was demonstrated in the Falklands War, aluminum can burn. For this reason, particular attention should be paid to insulating with fireproof material any aluminum bulkheads located where a fire may break out. The bulkheads that enclose the engine space, for example, will need special attention.

   It’s common practice to make the bulkhead adjacent to station 0 from the same metal as the hull. This “crash” bulkhead is usually at the forward end of the waterline. Some classification societies and authorities, including boats built to U.S. Coast Guard survey and those built for sale and use in Europe, require this first bulkhead to be located 5 percent of the load waterline (LWL) aft of the forward end of the waterline. This is a sensible rule, but it sometimes takes up valuable space. Boats built to the Coast Guard survey will need the accommodation moved farther aft than would otherwise be necessary.

   Some bulkheads may need stiffeners, depending on the size of the vessel, the metal used in the bulkheads, and the size of the particular bulkhead. These vertical L-angle or T-bar stiffeners are spaced about 12 to 18 inches (305 to 457 mm) apart and are installed with base of the L or T inward, thus making an excellent base for installing the cabin lining material. Some transverse stiffening also may be required. Check with the designer of your boat. The cavity formed by the L-angle can also be used to install the insulation.

   Concerning those bulkheads that you’re installing before the deck and superstructure are in place: make sure that the height above the sheer or deck will allow you to cut the correct cabin top camber later. We always recommend that you don’t try to cut the shape for the cambered decks, cabin sides, and top camber at this stage; simply allow the top of the bulkhead to stand up square from the sheer. This advice applies to all metal and plywood bulkheads. Later, you can mark out the deck camber, the lay-in of the cabin sides, and the cambers for the cabin top and/or wheelhouse top. These cuts may be more difficult to make with the bulkhead in an upright position, but they’ll be much easier to mark out with all of the bulkheads in place, rather than one at a time before the bulkheads are erected. More experienced builders may prefer to mark and cut the bulkhead tops as they install each one.

  If you’re building upright, and if many of the bulkheads are on a frame location, then it may be worth your while to include the basic bulkheads as part of the frame construction. Our advice is still to leave the tops square, as mentioned above. If you prefer, you may carefully work out the measurements and cabin-side angles of each bulkhead, and cut them to shape before installation.

PLYWOOD BULKHEADS

Intermediate and partial bulkheads are best built from plywood. You can use any suitable grade that has a marine glue-line. One way to test the durability of plywood is to boil it. A widely used 8-hour boiling test will give you a clear indication of its quality. Plywood provides stiffening and strength in many directions and will keep the weight of the interior down. Plywood bulkheads should be installed with the tops left square, so the areas above the deck can be marked and shaped at the same time as the metal bulkheads. If your plans do not state the thickness for the plywood bulkheads, keep in mind that the adjacent furniture and joinery will add stiffness and strength.

The transverse plywood bulkheads will need to be bolted in place, either to existing metal frames or to short sections of framing material commonly known as tags. The tags are 6 to 12 inches (150 to 300 mm) long and they’re spaced at the same intervals as their length. They’re welded to the hull to accept the bulkhead. The tags become necessary if a transverse bulkhead is located between frames, or adjacent to a frame but not at its exact location. It may be possible to alter the bulkhead’s location a small amount by bolting it to one side or other of the frame—but be careful not to create a space such as a berth that is too small or too long. You’d do better to install tags at a location between the frames. These tags provide more than adequate strength for bulkhead attachment. Don’t forget to pre-drill the tags at 4 to 6 inch (100 to 150 mm) centres to accept the bolts that will attach them to the bulkheads.

   As you’re unlikely to be able to purchase plywood sheets large enough to make the bulkheads in one piece, you’ll need to join or laminate the sheets somehow. The thickness of the plywood bulkheads will vary, depending on the size of the vessel as well as the purpose and location of the bulkhead. Transverse plywood bulkheads are generally thicker than longitudinal ones. The designer of your boat may have specified the thickness required.

   To form one complete bulkhead, you can use plywood of the specified total thickness and have this scarfed to the correct sheet size, or you can scarf or half-lap the sheets yourself. Our preferred method is to divide the thickness into two or more parts and then laminate two or more sheets face to face. For maximum strength, the joins can be widely staggered by alternating the joins in each layer. Plywood bulkheads, with the exception of those in the area of the mast in a sailboat, will not be exposed to great strains. The bulkhead adjacent to the mast can be strengthened by the addition of framing as required.

CORED BULKHEADS

If you are weight-conscious, you can consider one or more cored bulkheads. They can be used to divide the accommodation longitudinally, or to construct half-bulkheads such as those that form one end of a hanging locker or similar piece of joinery. The core material can be structural sheet foam, a light timber framing, or other suitable material that is both light and fire-resistant. The face plywood can be 3/16 inch (4 to 5 mm) and can be veneered with teak or a similar surface. The fiberglass bats used in house insulation are unsuitable for core material as they will soon shake down into a floppy mess when exposed to vibration and other marine operating conditions.

Bending and Installing Deck Beams

   The material for the deck beams can be flat bar, L-angle, or T-bar. It makes sense to use L-angle or T-bar, as either of these, when installed with the flange down, will provide an attachment point for the interior lining material. The insulation for the deck and cabin top will fit neatly in between the angle or T-beams.

The beams can be bent using the hydraulic-jack and steel-frame method, or you may prefer to have them bent by a professional metal shop. Your plan will at least give you a camber figure—for example, 6 inches in 13 feet (150 mm in 3.96 m). If you don’t have a pattern, but you do have the numbers for the recommended camber, you’ll have to make a pattern using the formula shown. If you have patterns for the various cambers, you should make a master pattern out of plywood or timber. You will use the pattern to check the beams as they’re bent to the correct camber and also as a general pattern for cutting bulkhead tops.

   In our designs, we recommend that you install the deck beams in one piece right across the hull. This method of installing the beams is much easier than trying to support short side deck beams while maintaining the correct sheer and curve of the deck/cabin-side intersection. Later, you’ll cut out the center of the beams and the section you remove will be re-bent for cabin-top beams.

You may need fore-and-aft Intercostal deck stringers, depending on the spacing of the beams and the size of your boat. The intercostals are best cut from flat bar and should be snaped in at the ends and welded in between the deck beams, as required. You could use a lighter angle for the Intercostal and have the flange level with the inside to provide a base for the lining material. The depth of the Intercostal should be the same as that of the deck beams as you may need to weld the underside of the deck plating to the Intercostal as well as to the deck beams themselves.

  Once all the deck beams are in place right across the hull, then you can mark the position where the cabin sides intersect the deck, support the beams, and cut at the marked line on each beam. Next, install a carlin to accept the inner edge of the side deck plating. The carlin will be a vertical length of flat bar running around the inner edges of the cut inner ends of the deck beams.

  You can, at this stage, make provision for hatches in the fore and aft decks or you can cut them out later and install any extra deck framing at that time. Once you’re satisfied with the framing for your deck, you can go ahead and plate the foredeck, side decks, and the aft deck area. Remember at this stage you are still tacking everything together; no long, continuous welding should take place until the whole structure is tacked together. See also the welding recommendations that come with your plans; usually only the outside seams are fully welded while other areas have stitch or chain welds as the final welding.

CABIN SIDES LAY-IN

At this stage, you’ll need to consult your plans regarding the correct lay-in for the cabin and pilothouse sides. Lay-in of the cabin or pilothouse sides refers to the amount by which the sides are angled inwards toward the centreline. In other words, the base (where the sides meet the deck) is slightly wider than the top (where the sides meet the cabin or pilothouse top). Too much lay-in will be most unattractive and be an invitation for leaky windows and may also interfere with your interior accommodation. Too little lay-in will make the superstructure on your boat look boxy and, at worst, can make it look as though it’s actually leaning outward at the top. How much lay-in is correct? Never less than 5 degrees and usually no more than 15 degrees is appropriate. When you cut the angle for the side lay-in, you may leave the tops square and cut the cabin or pilothouse top cambers after the cabin sides are installed.

If your vessel was designed for offshore use, your plans should indicate the size and location of the various hatches. If you’re the builder, the details of strength and suitability will lie in your hands. In the interests of safety, all hatches and companionways are best located on the centreline of the vessel. This is especially important for passagemaking vessels. In the event of a knockdown, an open hatch on or off the centreline can admit tons of water before it can be closed.

   You should take some time in deciding where and when to fit hatches. Before you start making holes in your decks, you need to have a firm idea as to the exact layout of your accommodation. You can simply plate the entire decks and superstructure, leaving the main hatchway available for access, and lay out your hatches at a later stage. Always keep in mind, however, that these areas need to be carefully planned and strongly constructed, especially in long-distance sailboats and power cruisers. The hatches that cover the openings in your boat may be called upon to withstand tons of water being dumped on the deck. Don’t treat them lightly; they need to be as strong as the hull.

   About the only places in which a steel boat can leak are around the hatches and other openings. It’s important to construct and fit these hatches so that they are absolutely watertight. Strong hinges and closing devices are a must. There are many cases where boats have been seriously damaged and lost through the fitting of inferior hatches. Combining safety with liveability, it’s best to fit hatches with hinges on both the forward and the after edges.

COMMERCIALLY MADE HATCHES

Deciding whether you will make your own hatches or use commercially made ones may be a matter of economics. Careful shopping can often reduce the prices to an acceptable level. Professionally manufactured hatches may add a nice finishing touch to your otherwise self-built boat. Most commercially made hatches will be manufactured from marine-grade aluminum.

   Unless you have your decks and superstructure built out of the same material as the hatches, you’ll need to isolate the hatches from the metal decks. A good commercially made hatch will have a precision-cast body of high-tensile alloy that will not corrode in the harsh marine environment. Tinted glazing is preferred, and it must be capable of taking the weight of more than one person and able to withstand the force of a breaking wave without deforming or breaking. Larger hatches should have three hinges that have been cast as part of the body of the hatch. To ensure water tightness under adverse conditions, a hatch that uses a neoprene O-ring seal is preferable to one that uses soft rubber strips. The neoprene is far superior to the spongy type of rubber seal and it will not deteriorate as quickly; also the O-ring neoprene seals are more resistant to sunlight.

MAKING YOUR OWN HATCHES

If you decide to build your own hatches, you can save a some money. It may be possible to construct them from materials you would otherwise throw away. We recommend that you build your hatches of steel, aluminum, or fiberglass. Timber and plywood hatches require considerable maintenance and, if of insufficient strength, offer a weak link in the security of your boat, so if you choose timber, make them strong. On the other hand, timber hatches and skylights can give a metal boat a touch of warmth, so if you’re prepared for additional work, both during and after installation, then timber hatches may be worth considering.

   Metal deck hatches can be built easily with inner and outer coamings. You can weld the coamings directly to the deck, making sure you’ve installed either deck beams or intercostals (or both) to reinforce the deck plating from below. You can install the reinforcing beams from underneath after you’ve cut the aperture for the hatchway.

Metal Hatches

   Obviously, it’s best to construct the hatches from the same material as the decks and superstructure. You’re more likely to have these materials on hand, and there will be no additional corrosion problems caused by mismatched materials. Arranging rounded corners on your hatches shouldn’t present you with any problems as all metals are capable of being formed into, say, a 3-inch (75 mm) radius. If you build your own hatches, some of the money you save can be invested in extra-thick acrylic-sheet glazing. Make sure it’s set in a suitable sealant and bolted in place with an adequate number of fastenings.

   Metal hatches can be built with inner and outer coamings; this arrangement is like a box made with a fitted lid. The inner box that acts as the coaming can be welded directly to the deck around the cut-out you’ve created in the deck or cabin top. The height of the inner coaming can be from 2 to 6 inches (50 to 150 mm), and higher in larger vessels. The hatch top can have sides of 2 to 3 inches (50 to 75 mm). The top will look best if it’s cambered similar to the line of the deck. This will look more professional, but it’s harder to build, especially if you plan to have acrylic, Lexan, or similar material included in the top of the hatch.

   Hinges for metal hatches are simple and easy to construct. They are basically one set of square tangs welded on the hatch cover to face a set of lugs welded at a 90-degree angle from the deck. A suitably sized rod, usually 3/8- to 3/4-inch (10 to 20 mm), depending on the size of the vessel and the hatch in question, is inserted through the tangs and lugs and the hatch cover will pivot on the rod. The rod will need a right-angle bend, a nut, or some similar stopper at one end, and a removable retaining device at the other end. If you install hinges on both the forward and after edges of the hatch, it will open either way. At sea, you should always have the hinges on the forward side, but in port or sheltered waters it may be useful to be able to open the hatch in more than one direction. On our current powerboat we have a hatch in the pilothouse top that can open straight up or in any one of four directions—a wonderful arrangement when one is seeking relief from the heat and needs to catch some breeze.

Any one of a variety of locking devices can be arranged to work with a metal hatch. In serious offshore cruisers, both sail and power, it’s important that the hatch can be screwed down tight to prevent pressurized seawater from forcing its way into the interior of the vessel.

   The top of the inner coaming will need to be fitted with a sealing strip, as with other types of hatches. The round neoprene O-shaped material is the most long lasting and, properly installed, gives a superior seal. A proper hatch should have a separate raised coaming of sufficient height placed ahead of it and on the two sides of it, to deflect the spray and rainwater streaming across the decks and/or cabin top. Don’t underestimate the power of water and its ability to force its way into any weak areas of your deck openings.

WOODEN HATCHES

Wooden hatches are relatively easy to construct but a perfect fit will take some woodworking skills. The best way to build these hatches is to build two boxes, one being the inner coaming and the other, the hatch itself. Obviously, one box will fit neatly over the other. The inner box should be made of 2-inch (50 mm) thick hardwood, and should be 4 to 9 inches (100 to 230 mm) in height. Usually, the larger the vessel, the higher the coaming. This box will be equal in size to the inner dimensions of the hatch opening. The minimum size to allow access by the average person is 20 inches (508 mm) square; however, you should decide what size hatches are most appropriate for you and likely crew members.

   It’s important the upper edge of this inner box (coaming) is perfectly square and level, as this is the edge that will contact the sealing material of the hatch itself. When you have constructed this basic square box for the inner coaming, you can cut a hole in the deck or cabin-top to match the inner dimensions of the box. Next, add reinforcing Intercostal and other beams underneath, around the perimeter of the hatchway.

Next, build the box that will be the hatch that will fit over the coaming. The hatch can be built out of 1 1/2-inch (35 mm) timber, and 3 inches (75 mm) high is about right. This hatch will fit snugly around the coaming but will have sufficient clearance to allow the completed hinged hatch to be opened and closed. So far, you have no top to your hatch. You can use 3/4-inch (20 mm) marine-grade plywood for the top, and screw and glue it to the frame. For a fancy finish you can glue and temporarily staple 1/8-inch (3 mm) mahogany or teak-faced plywood to the top of the hatch. In any case, the edges of the plywood top will need to have an outer timber strip to protect them.

You can have a Lexan or Plexiglas top instead of plywood, and you can have a combination of glazing and plywood for the top simply by fitting the ply top first, and then cutting out for the required amount of glazing. The glazed area should be of 1/2-inch Lexan or Plexiglas. When buying your glazing material, check the telephone directory and try to buy scrap material rather than specifying cut-to-size, for which you will pay a premium price.

   You will need to take some special precautions when working with the plastic glazing fitted to your hatch tops and portlights. The holes you drill in the plastic must be slightly oversized. You must allow for the different expansion and contraction rate, as opposed to the timber framing. You will most likely use tinted plastic, and this will expand in hot weather; if the bolt holes or screw holes are too snug, the plastic will crack and need to be replaced. Usually, the next size up from the screw size is about right for the hole. The safest type of screw is round headed with a flat surface on the bottom of the head where it meets the plastic; self-tapping stainless steel screws are ideal. Fancy screws, such as hex-headed, sheet-metal, stainless steel screws will give you a good looking and strong fastener. Sheet-metal screws have larger threads than woodworking screws and therefore provide additional fastening surface.

   The plastic should be bedded against the timber with as good a grade of silicone sealant as you can find. A small amount of the silicone sealant in each hole prior to screwing the glazing in place will ensure that the oversized holes remain watertight.

Hinges are fitted to the forward area of the outer coaming so that the hatch is aft-opening. The hinges should be heavy-duty and made of stainless steel or other non-corrosive metal. To secure the hatch from below, a number of catches and locking devices are available. One of the best is the type with screw-down devices, so you can dog the hatch down firmly onto its gaskets.

   When fitting the wooden hatch, assemble it completely with gaskets and then lower it into position. The best way to make the fit between the coaming and the deck or cabin-top is to first make sure the whole assembly is set up level. Next trace the shape of the cut required, allowing the coaming to make a good fit with the deck or cabin top. Now you can bolt or screw the coaming in place through the metal deck, working from underneath the deck. Make sure you bed the coaming in a suitable sealant.

Custom hatches can be made even more suitable for the rigors of cruising with a few simple additions. You can add an extra coaming on the deck or cabin top immediately adjacent to the hatch. This coaming should surround the forward edge and sides of the hatchway. It will be slightly lower than the entire hatch assembly and fit so as not to interfere with the operation of the hatch. The extra coaming will help keep water away from the hatch. The top of this extra coaming could be timber or metal. If you make it of timber, round off the top to give it the best appearance. In all cases, the sides can have holes in their bottom edges to allow for drainage.

   Another improvement to any hatch is to install eyebolts close to either side of the hatch assembly. You can use them in extreme weather conditions to lash the hatch down even more securely. The eyes need to be close to the hatch so you don’t stub your toes. Wood slats running fore and aft across the top of the hatch will strengthen Plexiglas tops and can improve the look of the hatch at the same time. These 1 by 1 inch (25 by 25 mm) timber slats can be screwed into the outer frame and then screwed to the acrylic from underneath. The slats will take some of the force and distribute the weight of persons standing on the hatch, or the weight of a heavy breaking wave. You can also make canvas covers for all of the hatches. Not only will you need these in hot climates, but they can also be a safety factor when included as part of the lashing-down arrangement

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ACCESS HATCHES

Access hatches, as opposed to hatches used only for ventilation, must be of a size sufficient to allow even a large person to enter and exit the boat in an emergency. The minimum size for an average person, as we’ve already seen, is 20 inches (508 mm) square, but don’t make hatches unnecessarily large. They must be able to withstand all that the sea can offer. You should be able to open all your hatches from both outside and inside the vessel, and you should be able to lock them to deter unauthorized intruders. Hatches in accommodation areas should be built with some form of glazing to admit light and add a spacious feeling to the interior.

COMPANIONWAY HATCHES

The main access hatchway can be in the form of a sliding hatch, a hinged hatch, or a quadrant companionway type hatch, as illustrated. Sliding hatches should not be simply a sheet of plastic running in the simplest of aluminum tracks, even though this is sometimes seen on production powerboats. Build, or buy and install, a proper seagoing hatch as your main entry and exit point.

   The companionway hatch consists of two main elements: the runners, which fit on the cabin-top, and the hatch, which slides on or in the runners. The runners and the hatch may be constructed of timber or metal. If timber runners are used, you’ll need 3-inch-high by 2-inch-wide (75 by 50 mm) timber. The timber runners could be deeper, and could be bolted directly to a set of Intercostal beams situated around the perimeter of the hatchway. The runners will need to extend beyond the opening; the length is twice the hatch length plus 3 inches (75 mm). Where they extend over the cabin top, they’ll need to be screwed from inside, through to the timber.

   The tops of the runners are faced with heavy (say, 1/4 by 2 inch, or 6 by 50 mm) brass strips that act as runners for the hatch top. The brass strips are set in silicone and screwed to the runners with flathead screws set flush with the surface. When it’s properly set up, the hatch must run smoothly on the brass slider.

   The sliding hatch is another box, with the frame built of 1 1/2 by 2 inch (35 by 50 mm) hardwood. The corners can be half-jointed. Considerable care is needed to ensure that the frame is a true rectangle and sits perfectly flat on the runners. Around this inner frame, an outer frame is constructed from 1 1/2 by 4 inch (35 by 100 mm) hardwood. The outer frame is glued and screwed to the inner frame, with the tops of both frames flush and the outer 4-inch-deep (100 mm) frame acting as a guide to allow the inner frame to slide on the runners. The whole arrangement must slide smoothly. A hatch that jams is in no way desirable aboard any boat. Now you need an arrangement to keep the hatch on the runners, and you can do this by gluing and screwing a 1/2 by 1/2 inch (12 by 12 mm) cleat inside the outer frame 1/8 inch (3 mm) underneath the brass runner. Now the hatch has to be slid onto the runners from the front. The forward and after ends of the hatch are finished off with hardwood plates. The companionway end can have a handle or grip built into the top. The bottom of this facing board will need to be shaped to clear the cambered cabin top as it glides (we hope) forward to its fully open location.

   If you have the recommended garage, then the front should be large enough to cover the aft end of this arrangement. Incidentally, the garage houses the hatch when it’s open. The garage is particularly important in forward-facing sliding hatches, as it helps to divert water away from the open companionway. It also partly provides a neat cover for the runners and the open hatch, eliminating one area where lines can snag and toes can be stubbed.

   The front facing of the hatch, with the handgrip built into the top, will also need to accommodate the hasp part of your hasp-and-staple locking arrangement. The top of the hatch can be finished with 1/8-inch (3 mm) teak plywood and the whole structure coated with epoxy and light fiberglass cloth for a long life.

   The top of the hatch can be three layers of 1/4-inch (6 mm) plywood, and if you’ve taken our advice and made the top match the cabin top camber, you’ll find that the plywood will laminate into a strong and durable top. A trim strip will be required for the outer edges of the plywood top to seal them from the elements.

   When you’re building a timber or plywood sliding hatch above a metal cabin, the hatch opening can be finished off inside with a timber trim strip of suitable width. You’ll also need washboards (vertical hatch-boards or drop-boards) that will fit in preinstalled metal channels to complete the closure of the main-access companionway.

It’s worth noting here that any timber you attach to your steel hull or superstructure should be given at least three coats of epoxy resin, which will go a long way toward stabilizing and protecting the timber. All timber runners, hatch coamings, and the like must be set in silicone before they are either screwed or bolted in position. Space the screws or bolts at 3-inch (75 mm) intervals.

DECK PRISMS

Another form of underused light-admitting device is the deck prism. These wonderful devices admit much more light than their size would indicate, and they can be installed to be absolutely watertight and secure from the ravages of man and the sea. Check with your local hatch manufacturer and other equipment suppliers to see what they have to offer in this area. If you fit prisms, make sure your crew is well protected from contact with the sharp inside edges—but do not let this last statement put you off; deck prisms are great for admitting the most light with the minimum of hassle.

Portlights and Windows

   Portlights and windows can be opening or fixed, but it’s a fact that the opening variety, no matter how well constructed and maintained, will always be a source of leaks and worry for the crew. It’s often desirable to have one or more windows or ports that can be opened; however, it’s wise to keep their number to an absolute minimum. The plans for your boat will no doubt give you some indication of the size and location of the ports and windows. Our advice is use only fixed portlights and rely on opening hatches to provide adequate ventilation.

   If you’re planning to use opening ports, they should be professionally made and of the highest quality you can afford. Most commercial ports are made from marine-grade aluminum, so if your boat is built of steel or copper-nickel you’ll need to isolate the aluminum from the other metal. Neoprene is commonly used for this purpose. Don’t forget to use sleeves in the bolt holes where the ports are bolted to the hull or superstructure. Occasionally, you’ll find steel-framed professionally made ports, but they’re generally made for very large vessels so they may not be suitable for your boat.

There are many ways in which the windows can be fitted. One popular way is to set the windows back into the cabin sides or into the hull. To achieve the latter result, the window aperture is framed with an inward-facing, L-angle, shaped flange. The bottom of the L is where the window or fixed portlights will be set in sealant and bolted in place.

   As you will realize, this is a more complicated procedure than simply bolting the window into a hull or cabin-side cut-out; however, the results are worth the extra effort. Set-in ports and windows give a vessel that extra touch of quality that not only enhances pride of ownership, but one day will return dividends in a better resale value. Forward-facing wheelhouse windows that will be fitted with windshield wipers will need to be glazed with toughened glass instead of the usual acrylic favoured for many other boat windows and ports.

   If it’s well made, the simplest portlights or window can have an appearance that belies its low cost. The design and method of installation is simple. You cut a hole 1 to 1 1/2 inches (25 to 35 mm) smaller than the overall size of your port or window and fit and bolt a larger piece of Plexiglas or similar plastic over the aperture. The glazing is set in silicone, the holes for the bolts are drilled slightly oversized, and the corners of the hole for the portlights, and the covering Plexiglas, are all radiuses.

   You can use clear silicone, but it’s preferable to use silicone that matches the colour of the area of the boat into which the port or window is being installed. If the bolts have hexagonal heads, and you line up the slots in the heads, you’ll improve the appearance of the glazed area. If the ports or windows are located in a high-traffic area, such as adjacent to the side decks, then you should have bolt heads that fit flush with the glazing and thus avoid scratching crew members who brush by the window. Be careful when making countersunk holes to allow bolts to fit flush. Acrylic can be induced to crack if it’s handled too roughly during the shaping and assembly stage.

   Make sure the windows don’t have an overly large area without sufficient support in the underlying cabin or wheelhouse side. Plexiglas and similar acrylic materials come with a paper protective covering; never remove the bulk of this until the boat is completed and ready for launching. You’ll need to remove a strip of the paper, of course, after you’ve drilled for the bolts but before you install the window or portlights.    The thickness of the glazing will be between 3/8 and 3/4 inch (10 and 20 mm), depending on the size and area of the aperture.

   For most windows and ports, you can use Plexiglas or the harder and more scratch-resistant Lexan. You can dress up the outer edges of these bolt-on windows by using timber, stainless steel, or other suitable metal frames that can be cut to, say, 1 or 2 inches (25 to 50 mm) wide and bolted in place at the same time as the window is installed. If you use metal, it can act as an outer washer for the fastenings and will generally enhance the appearance of the windows and ports on your boat.

With powerboats, where the boat is more or less always in an upright position, and where the boat is not designed or built for extended ocean voyaging, you can be more liberal with the expanse of glazed area. Most powerboats have at least one forward-facing opening window adjacent to the inside helm position. This opening window can admit copious quantities of fresh air, and when it’s open it gives you better vision ahead in fog or poor visibility.

   Even in powerboats, we find that opening windows, usually of the sliding variety, are a source of problems. Sooner, rather than later, the rubber or other material used in the bottom track for the glass will perish and allow water to enter. In some steel powerboats, it’s common practice to have the large side windows fitted without any provision for insulation. Perhaps the designers and builders feel that the expanse of glass takes up so much of the available area that it is not worth insulating the remainder. The problem is that when plywood lining is attached directly to the steel cabin side, the resulting condensation can cause problems. In one case, it was natural (though wrong) to blame a leaky window for causing discoloration of the teak plywood lining. It took some time before the culprit was diagnosed as lack of insulation in the cabin side, which caused condensation. It would have been too expensive to remedy the situation, but luckily it was discovered that a dehumidifier would solve the problem. Lesson: Always insulate all areas of your accommodation.

OUTER DOORS

As a rule, outer doors are seen in powerboats, especially trawlers. If you wish to have a door opening in the side of the accommodation, usually near the helm location, make sure it’s properly designed, fitted, and suitable for marine use. Marine doors are usually of a more robust construction than sliding windows and are therefore easier to maintain and keep watertight.

   Side doors in a trawler yacht’s cabin can be built of timber and may be arranged to slide; or, if you have a very large yacht and wide side decks, then it may be possible to have the door hinged at the forward edge, or perhaps open inward. On smaller boats, a half-height, side-access door adjacent to the inside helm position may be found useful. All doors, especially sliders that are either outside or inside the accommodation, should have a means to secure them in the open position, as well as when closed.

A recent report told of a boat owner receiving severe injuries to his neck from an unsecured aluminum sliding door. Patio-style aluminum doors at the aft end of a powerboat’s main saloon? Ugh! The sliding variety, especially, are famous for lopping off fingers. And the large glass area is vulnerable to being broken in a variety of ways.

If your powerboat is of the aft-cockpit variety, then you’ll most likely have a metal aft bulkhead in which you can fit a pair of timber doors. The top one-third of the doors can be glazed, and you’ll have all the light you need. As the cockpit and after deck is usually well protected, the timber doors will need little maintenance.

On a similar subject, you may wish to lock some of the interior doors; this may slow down an intruder.

   The dimensions of this arrangement are most important and can influence the safety and comfort of the boat in many ways. It’s desirable, but not always possible, to have the cockpit seats measure 6 feet 6 inches (2 m) in length to allow a person to lie full-length. The width of the cockpit is best arranged so a person can rest one or both feet on the seat opposite; this usually results in a well that is 2 feet 3 inches (686 mm) wide. The depth is best at 1 foot 6 inches (457 mm). Seats should be between 1 foot 3 inches (381 mm) and 1 foot 6 inches (457 mm) wide. For comfort behind your knees, the inboard edge—the intersection of cockpit side and the forward edge of seat—of the cockpit seat should be rounded, radiused, or bevelled.

   The height of the seat back (usually part of the coaming) will vary depending on the design; however, about 2 feet (610 mm) seems to work out well for most people; the back should lean backward about 5 degrees to be comfortable when sitting in a level cockpit. All cockpits should be self-draining, with two separate outlets of generous size, a minimum of 2 inches (50 mm) in diameter. The cockpit drains should be fitted with sea cocks that can be closed when required. Finally, you should have a reasonable view forward when you’re seated in the cockpit. This is easier said than achieved, especially if there is a pilothouse ahead of your cockpit. The choice between center cockpit and aft cockpit is usually governed by your choice of interior layout. This choice has become blurred with the advent of staterooms fitted beneath and around an aft cockpit.

   Metal cockpits can be framed up using L-angle or flat bar, depending on the size of the vessel. Boats under, say, 30 feet (9.14 m) can use flat bar, and larger boats can use L-angle placed flange-down. Provided the transverse framing is spaced the same as the hull’s, a minimum of fore-and-aft reinforcing should be required. Most boats today have cockpit cushions, so these need to be considered when laying out the area. Self-draining arrangements for the well are obvious, but don’t forget to drain the seats. Wet seats and continuously wet cushions make for very uncomfortable sitting, so consider how you can best drain these areas. A teak grating in the well adds a nice finishing touch to any cockpit.

DECK COVERINGS

Your metal deck will need some form of treatment to provide a non-slip footing as you move about the boat. The least expensive treatment is to apply a special paint that contains grit. Many metal boats use this paint-grit combination, and provided it’s installed in a proper manner it can look attractive and it does work well in practice. When you’re installing a painted non-skid surface, you should leave small borders around various fittings and alongside the cabin and inside the bulwark and so forth—places that do not have grit added. Be careful how you lay out these un-gritted areas, though, as you don’t want to leave skid-inducing shiny spaces in high-traffic areas. If the un-gritted areas are no more than 1 1/4 inches (320 mm) wide around any feature, you shouldn’t have a problem. You can always fill in any problem spaces with gritted paint.

   The next step up in cost and appearance is to use a deck covering like Treadmaster or a similar product. These coverings are composite materials formed in patterned sheets suitable for gluing to your deck. When laying out this covering, you should use a similar pattern as suggested for painting decks with gritted material. Available in a range of attractive colors, these products are bonded to your deck with special glue.

   The diamond pattern on some of these sheet products can be hard on your bottom and other areas that may come into contact with the deck. So don’t use it on cockpit seats or similar locations. There are alternative, less harsh patterns that can be used where a user-friendly, non-slip surface is required.

   Personally I do not favour timber-laid decks on metal boats. If you plan to keep your boat longer than, say, 10 years, then you can expect have some problems if you install a laid timber deck on a steel boat. Problems with laid timber decks are not restricted to metal boats; many fiberglass boats that are manufactured by the most reputable companies also have problems with the laid timber decks once the boat has reached a certain age. The main problems are caused by the breakdown in the caulking materials. The caulking will develop hairline cracks after a few years and this allows water to seep through to the metal decks below. If you are installing or renovating a teak deck, under no circumstances stint on the quality of this caulking material.

   Recently a simulated teak deck material has become available and this plastic-based (for want of a better description) material will be worth your investigation. It closely resembles teak and is laid in a similar manner, so check out this material before you consider a wooden deck.

However, some of you will settle for nothing but a laid wood deck. You may be surprised to learn that there are species of timber other than teak that are suitable for laid-plank decks. In Australia, beech is widely used, and in the United States quarter-sawn Douglas fir has been used for the same purpose. Nonetheless, teak is the premier material and the one you are most likely to be using to finish the decks of your metal boat in style.

   After you decide that a laid deck is for you, the next step is to determine if you’re going to have a “wannabe” teak deck or the real thing. The “wannabe” type is usually 1/2 inch (12 mm) or less thick, and in most cases it will not do justice to your boat or to the craftsmanship needed to install any laid deck. A “proper” laid deck should have planks of at least 5/8 inch (15 mm) and preferably 3/4 inch (20 mm) minimum thickness.

   There are many ways to install this deck on a metal boat but all will involve setting the planks in some form of bedding compound. Again, we can take a lead from Dutch builders who have been successfully installing laid decks on steel and other metal boats for a long time. The outer planks will need to be fastened to the steel deck itself. The inner planks may simply be set in the bedding compound and caulked.

The regular planks should be about 1 3/4 inches (42 mm) in width. The outer and inner covering boards, king plank, and other featured planks around hatches and vents will be wider, usually 4 to 6 inches (100 to 150 mm), depending on the size of the boat and the way the deck is installed. The outer covering board is a misnomer in this case, as there should be a space between the edge of the teak covering board and the edge of the deck to create a channel for water to run alongside the outer teak plank and on out through the scuppers.

   The bulk of the fore-and-aft planking can be laid in several ways. It can follow the outer shape of the hull, generally known as the "swept" style of fore-and-aft planking,