US$70,000. Is that realistic?


Why Aluminium?

Aluminium is a very consistent engineering material with excellent mechanical properties and a long service life. It is an economical material which costs about US$1.50 per pound. It can be left unpainted in the marine environment and is a very tough material comparable to steel when experiencing excessive loads as can happen in collisions or reef groundings. Functional in the field repairs can be made with hand tools and will serve until the vessel is in a port with MIG welding facilities.

The primary structure is designed for low labour input assembly by professional welders. The low labour design allows the effective use of professional fabricators and removes the need for the owner builder to purchase expensive MIG welding equipment, or to develop welding skills, or to have a covered shed for construction with access for launching. These are all provided by the professional fabricator at similar or reduced overall project cost. The material would normally arrive at the fabricators precut by computer by your material supplier. Very large sheets are used where practical including 40'x8' sheets.

The construction of the hulls is with a frameless design utilizing relatively thick material which both assists construction and provides for a tough primary structure. Included here are some photos of a 36' monohull of Brent Swains design which uses framelsss construction in 1/4" aluminium.

Note the chine that only runs for about a third of the length of the hull.

The fore and aft sections of the hull are developed surfaces and while bent in two directions are not compound curves and are readily formed from sheet material.

A view of the interior showing stringers, chine and no frames!

Copyright © 1998 Tony Bigras.