I have been looking at aluminum boats for the last couple years now with an
eye towards how they are built. I have noticed a lot of them will have 'V's
folded or stamped into the hull along the length for strength. I don't see
anyway that a backyard builder could do this practically. Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?

On Mon, 19 May 2008 11:34:18 -0700, "Bob La Londe"
wrote:

I have been looking at aluminum boats for the last couple years now with an
eye towards how they are built. I have noticed a lot of them will have 'V's
folded or stamped into the hull along the length for strength. I don't see
anyway that a backyard builder could do this practically. Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?



They may allso be there to help longnitudnal stability or for spray
control. You can get the strenghth by rivetting or welding on
stringers made from aluminum angle.on the inside or bend some flat
stock 3 times to make a V shaped piece. that could go on the inside or
outside of the hull.

"Drew Dalgleish" wrote in message
...
On Mon, 19 May 2008 11:34:18 -0700, "Bob La Londe"
wrote:

I have been looking at aluminum boats for the last couple years now with
an
eye towards how they are built. I have noticed a lot of them will have
'V's
folded or stamped into the hull along the length for strength. I don't
see
anyway that a backyard builder could do this practically. Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?



They may allso be there to help longnitudnal stability or for spray
control.

A V mounted above the water line sweeping with the lines of the hull is
almost always there for spray control. I think they even call it a spray
rail.

You can get the strenghth by rivetting or welding on
stringers made from aluminum angle.on the inside or bend some flat
stock 3 times to make a V shaped piece. that could go on the inside or
outside of the hull.

Yeah, that's basically what I figured

Bob La Londe
www.yumabassman.com

All those integral shapes provide rigidity in very light sheet material.
These boats are typically riveted, or welded in extremely controlled
environments.

For a homebuilt, you will probably weld, using much thicker material; I
understand that most welders can do good work in 3/16 plate, the talented in
1/8, and only very very expert can weld material lighter than that with much
success.

These thicker plates require less framing or complex bending than the thin
material.

For a full discussion, take a look at Pollard's Boatbuilding with Aluminum:
http://www.amazon.com/Boatbuilding-A.../dp/0070504261

Have fun!
Sal's Dad



I have noticed a lot of them will have 'V's
folded or stamped into the hull along the length for strength. I don't
see
anyway that a backyard builder could do this practically. Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?



They may allso be there to help longnitudnal stability or for spray
control.

A V mounted above the water line sweeping with the lines of the hull is
almost always there for spray control. I think they even call it a spray
rail.

You can get the strenghth by rivetting or welding on
stringers made from aluminum angle.on the inside or bend some flat
stock 3 times to make a V shaped piece. that could go on the inside or
outside of the hull.

Sal's Dad wrote:
All those integral shapes provide rigidity in very light sheet material.
These boats are typically riveted, or welded in extremely controlled
environments.

For a homebuilt, you will probably weld, using much thicker material; I
understand that most welders can do good work in 3/16 plate, the talented in
1/8, and only very very expert can weld material lighter than that with much
success.

Bull****. I am a mediocre welder, and I can weld .062 all day with no
issues. A good welder can do thinner than that.

THere is no mystery in welding aluminum. It just takes practice and a
decent welder.

These thicker plates require less framing or complex bending than the thin
material.

For a full discussion, take a look at Pollard's Boatbuilding with Aluminum:
http://www.amazon.com/Boatbuilding-A.../dp/0070504261

Have fun!
Sal's Dad




I have noticed a lot of them will have 'V's
folded or stamped into the hull along the length for strength. I don't
see
anyway that a backyard builder could do this practically. Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?




They may allso be there to help longnitudnal stability or for spray
control.

A V mounted above the water line sweeping with the lines of the hull is
almost always there for spray control. I think they even call it a spray
rail.


You can get the strenghth by rivetting or welding on
stringers made from aluminum angle.on the inside or bend some flat
stock 3 times to make a V shaped piece. that could go on the inside or
outside of the hull.





--
“TANSTAAFL”
__________________________________________________ __________________________

America: Ironically, the safest place to be anti-American.
__________________________________________________ __________________________
"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3

On May 20, 4:34*am, "Bob La Londe" wrote:
I have been looking at aluminum boats for the last couple years now with an
eye towards how they are built. *I have noticed a lot of them will have 'V's
folded or stamped into the hull along the length for strength. *I don't see
anyway that a backyard builder could do this practically. *Would a home
built aluminum just be built with a structural frame with pieces going in
both directions like a wood boat?

I was building aluminum plate boats in the 5.6metre-7metre range for
about a year, these were fairly expensive high quality fishing boats
with water ballast keels and various layounts including cuddy cabins
and walkarounds. These were plate aluminum boats, using materials up
to 6mm (1/4") so they were fairly rigid, but still had only a single
hard chine in the hull where the V bottom joined the side plates, then
a "step" in the sides. You can see the boats here;

http://www.barcrusher.com.au/

They are not overly complex to make, though a good aluminium MIG with
synergic pulse is a huge help. Try Fronius (my preference) or Kempi,
but dont expect too much change from $10,000. The forming/cutting
tools are very basic. Any tungsten tipped blad for woodworking is
good for aluminum. You can use common woodworking table saws, drop
saws etc. The machine used for putting the step in the side panesl is
not expensive, its just a simple offset roller, you can buy cheap ones
for a few hundred dollars. You then mark the sheet with a marker
where you want to have the step, then roll it by hand. Very basic.

Knowing where to put the mark is the real skill same with shaping
the side/bottom sheets, the shape you cut them to is quite complex and
not easily worked out. Expect to waste some materials ($$$) if you
havent done this before and have no design/CAD knowledge. The
simplest way to get a feel for it is to make scale modesl with
cardboard. Dont try to be real fancy here, 10 minutes/model is
enough. Just mark out on cardboard, cut, and tape. See what
happens. Remember you'l need a very good fitup at this scale for it
to translate to a weldable product at full scale.

Best Regards,
Shaun

On Tue, 10 Jun 2008 07:21:02 -0700 (PDT), imagineero
wrote:

They are not overly complex to make, though a good aluminium MIG with
synergic pulse is a huge help. Try Fronius (my preference) or Kempi,
but dont expect too much change from $10,000.

One word: rivets

Casady