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.
