Braking Aluminum
"Bob La Londe" wrote in message
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"Steve W." wrote in
message
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Bob La Londe wrote:
I have a copy of Pollards aluminum boat
building book, and I have read it.
It looks like he mostly plans on boats to be
all cut pieces and welded.
That's great for big boats or even for some
small boats, but braking seems
like it would make more sense if you have
access to a brake big enough.
Some of the small boat designs (think shallow
draft skinny water boats)
would really benefit from a mostly bent hull.
Aluminum sheet can be had in
pieces large enough to make most of a hull out
of one sheet. Some cutting
and welding is still needed obviously, but if
you could brake the keel,
chines, and bottom of the transom only welding
the front and the sides in
the back you would have an inherently stronger
and more rigid boat for rough
service.
The problem of course is how do you brake a
piece of metal that big?
Yeah I know a giant hydraulic brake would be a
good answer for the
commercial boat builder once they have the
capital for it, but how does the
backyard boat builder do it? Are they stuck
with all cut and welded pieces,
or hauling their sheet to somebody with a
giant brake to do it for them (if
there even is somebody with a brake big enough
in the area that hires out)?
I think the main reason is stress on the hull.
The cut and welded seams will be stronger and
take the constant bending better than a simple
bent section of aluminum. Keep in mind that all
boats flex small boats flex a LOT. Aluminum
doesn't like flex but with the cut sheets the
flex of each panel can be dissipated better
than if you used a single piece. Plus since
many of the pieces come together over
frame sections the cut sheets get welded to the
frame and each other in the same step.
Commercial boat builders (in some cases using
what I would consider the wrong alloy) make long
brakes in aluminum all the time. Most small
boats have rolled or bent ribs in the hull for
strength.
What alloy?
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