Wednesday, December 1, 2010

Types of wooden hull construction

Some types of wood construction include:

arvel.With this technique the planks are fit together edge-against-edge. They do not overlap each other. They are fixed at the frames and the outside of the hull is smooth. The edges are beveled so that they meet (or almost meet) at the inside, leaving an open seam on the outside that is generally caulked with cotton and then filled with a filler to obtain a smooth surface. This was one of the earliest methods of boat construction and is still sometimes used today. The wood in carvel boats was intended to move, and will expand and contract as the hull absorbs and emits moisture and as temperatures change. The integrity of the framing and the fasteners is of the utmost importance. New carvel-planked boats will usually run and sail without leaking, but older boats will almost always leak at least a little, and sometimes a lot.

ouble-planked.The hull is constructed of two layers of edge-butted planks, one layer on a diagonal to the other and almost always with a mastic or painted canvas between the planking layers to prevent leakage. The double planking added some structural rigidity to the hull, but hull integrity still depends on the integrity of the fasteners and the framing. There is also the cold molding method of construction which is basically a refined modification of the double planked method, using thin sheets of wood bonded to each other in complex curves.

apstrake.The exterior edges of lightweight planks are overlapped slightly, and then beveled and riveted or screwed to frames, giving the hull itself an integrated structure, allowing some reduction in interior framing as compared to carvel construction. This technique was developed in Scandinavia over 1000 years ago, and is still used today in contemporary boat building. The Lyman line was one of the most famous of the lapstrake constructed boats in the United States, and many Lyman boats are still in use.

lywood.The major advantage for plywood boat is it has relatively light interior framing and more integrated structure. This plywood boats became popular for the builder in the 50’s and are still commonly built today, usually by small shops and individuals. There are a number of different methods of fastening the plywood, from screws to polymer adhesives to “stitch-and-glue”. Good plywood is an excellent material for boat construction, but is vulnerable to rot, deterioration, and delamination.

trip-planked.Strip-planked boats also became popular in the 50’s and are still being built by contemporary boat builders. Square or almost square strips of wood are laid over relatively light framing and bonded together edge-to-edge, originally with marine adhesives such as resorcinol but more recently with epoxies. They are the most watertight of wood constructed boats, and relatively easy to repair. The strip-planking gives the hull great structural rigidity. These boats are sometimes covered by fiberglass, an idea that works better in theory than it often does in fact.

esin over wood.Resin and fiberglass always cloth over strip-planked or plywood boats in the new construction. It can work well if epoxy resin is used and applied to new or good wood under proper conditions. There have been many attempts to coat old hulls with cloth and resin, and most of the time they result in failure.

there is thousand web about this but
below is some of web that i refer from.

more info Click here:   
  1. wikipedia-boatbuilding
  2. Mark Smaalders Yacht Designs 
  3. rotdoctor
  4. azom

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