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42' and 50' Cruising Sailboat Designs
Description of the 50 1/2 ft Sailboat Hull
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This is a 1/8 scale model of the 42.01 ft hull. The 50.5 ft hull is a little sleeker.
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The advantages of dead rise in a sailboat hull.
A hull with considerable dead rise will give a more gentle ride
against weather because the bows and the bottom slide easier into the waves or into the water
surface. This is important when one has to go against the weather over long stretches, or days on end.
It is also easier on the hull and its integrity is more safe-guarded.
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Dead rise allows for less wetted surface as the hypotenuse (to which dead rise compares) is less in length
than the sum of the other two sides of a triangle to which most racing hulls approximately
conform. We are not truly dealing with triangles, but the idea of triangles is there.
In lighter wind conditions a
sailboat with dead rise will slide easier through the water.
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Under most sailing conditions dead rise coupled with a full keel
allows for easier flow of water than a racing hull with a fin keel - first, because most
sailing conditions do not allow a sailboat to start planing, and often do not allow
the keel to become optimally effective, causing unnecessary turbulence.
Second, sailboats of about forty feet and over with dead rise and full keel are always
in optimum sailing condition in any weather on the water, no matter the conditions they meet.
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Sailboats with dead rise and a full keel track better and are easier kept
on course. Such hulls consume less electrical charge when an automatic pilot is used to keep
them on course.
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The 50 ft hull was derived by scaling up the length of the 42 ft hull by a factor of 1.2, and the width and the height by a factor of 1.1.
The resulting pertinent data of the hull are as follows:
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L O A: - - - - - - - - - - - 50.49 ft
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station spacing: - - - - - - 3.75 ft
- freeboard: - - - - - - - - - 5 ft
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designed waterline length: 37.50 ft
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draft: - - - - - - - - - - - - 5.50 ft
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Beam: - - - - - - - - 14.85 ft
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beam @ dwl: - - - - 12.31 ft
- displacement (light): 469 cubic ft / 30.000 lbs
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wetted surface: - - - 478 square ft
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hull speed: - - - - - - 7.8 knots
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The inside of the hull from sole to the underside of the deck will be ceiled.
This is a builders' term for applying, long, narrow, strips of wood tightly against each other
against the frames along most of the inside of the hull.
By doing so one can dispense with or lighten a lot
of structural members as the ceiling stiffens and strengthens the hull
considerably. It is common procedure on wooden boats. In my design the wasted
space between the hull and the ceiling are filled with fire-retardant, closed-cell,
hard foam. Other waste spaces inside the hull will also be filled with foam.
This gives all kinds of advantages. It stiffens the boat even more,
prevents the boat from consuming itself in a fire, it insulates against noise,
heat and chill - and with some special other arrangements - will make the hull buoyant
when sprung a leak. By using diesel power one prevents gasoline fires and explosions
that occasionally occur on gasoline-powered hulls.
Also, the entire keel is protected from accidental collisions with under-water
objects by its lead ballast
The upwind mechanism makes the boat more maneuverable than other sailing vessels,
very much needed in the busy, crowded close-quartered harbors of today.
These designs would make marvelous boats to lease out with owner-on-board as skipper, especially
so for the 50.5 ft model.
The hull is designed so that starting at about 15 degrees heel to about 35 degrees heel
air can be introduced beneath the hull, which reduces the wetted surface and gives
extra buoyancy at the leeward side of the hull. Air can be bled from scuba tanks or from industrial
compressed-air tanks. In light wind conditions the boat can be heeled over using a special-design,
weight-transfer system, that is easy to use and is intended to help reduce heel
in strong winds on long tacks while cruising.
For pictures of the, 1/8 scale of the 42 ft, model hull @ approximately 2 knots speed click below on "one eighth scale, remote-controlled, sloop.htm"
As can be seen, at 2 knots (equivalent to 5.6 knots of the full-scale hull),
the hull moves almost effortlessly through the water.
Performance of a 1/8 scale model of the 50.5 ft hull, would be even better and smoother than the proportionately beamier 42 ft hull.
Nothing comes even close to owning a well-designed,
wood-constructed, cruising sailboat.
This page was revised on 08 28 2010
Innovative Cruising Boat Designs
Nothing comes close to owning a well-designed, wood-constructed, cruising sailboat.
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Phone 828 393 8569 USA
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© 2006 Copyright Johannes P. and Carol A. van Krieken. All rights reserved.
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