"Del Cecchi" wrote in message
...
wrote:
On Jan 11, 8:34 pm, "JoeSpareBedroom" wrote:
wrote in message

...

Finally going to make the plunge and buy an aluminum boat, but i am
confused. Our goal is to buy a boat that will last for many years to
come and also turn heads when on the water. The more i talk to
salesman the more BS i hear. What should i be looking for as far as
the quality of the welds, some look like art and some look like my son
who is 12 tried to weld for the first time. Does the apperance of the
weld matter? We are looking at a 200 Sea Runner Hewes Craft right now,
any comments would help at this point
Thanks
I own a Lund, and the company makes a big selling point of the fact that
their aluminum hulls are double riveted. Welding is not mentioned
anywhere
in their literature, as far as I've noticed. I've been beating the crap
out
of the boat since 1999 and it's as tight as the day it was new.

www.lundboats.com
Thanks for the feedback
I appreciate your coment about rivetted boats but my wife said noway
to riveted boats, he dad had one and it always leaked. Infact you
should have seen the dirty looks she gave one of the salesman when he
was trying to sale us on a riveted boat. What would you look for or
like to see as far as welds?

Here in minnesota there are riveted boats all over the place. Lund and
Alumacraft are the two biggies. If they leaked, they wouldn't be so
popular. Boeing uses rivets also but not on boats.


Riveted boats were lightweight, thin Aluminum. Welding thin aluminum just
does not work in boats or airplanes. Too much flex. Will break next to the
welds. Been their, got the tee shirt. My 14' alum boat got a crack in the
bottom from the trailer bunk. A keel roller had collapsed and the bow strap
caused the boat to press on the front edge of the bunk. Had it welded and
had to get it welded again. The Northwest boats were designed to run
shallow water with rocks. Sure the get holed at times. But it is normally
a very sharp rock that does it.

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...

wrote in message
...

First, rivets are used on aircraft for the following reasons, not all of
value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.

I think aluminum welds are fine as long as they are reinforced or the
sheets are relatively thick. Thin sheet (seam) welding of aluminum is
prone to cracking when subjected to even a little flex as compared to
other metals. Maybe someone with knowledge of metallurgy can explain the
crystalline structure, etc. My opinion is based on experience in
industry.

BTW, I think flex is much more important in airplane wings than you give
it credit for. Next time you fly, note the location of a wing tip as the
airplane begins it's take-off run and watch it as you become airborne.
While flying in turbulence, watch the tip of the wing again. There's
quite a bit of wobbling around going on out there. Welded aluminum panels
wouldn't last long, nor would the wings if they were designed to be stiff
rather than being allowed to flex.

Eisboch

But my point being, do you want that much flex on a 17-19' boat?

I would think not. But on an aircraft, this is good. The wings are in
effect shock absorbers for up/down drafts and air density changes. But I
don't think this level of flex is needed nor desirable on a small boat.

"-rick-" wrote in message
news
Short Wave Sportfishing wrote:

Riveted aluminum boats tend to be sounder than welded boats and as a
general rule, easier to repair. The better aluminum boats, like Lund,
Starcraft, Princecraft, are riveted boats.

Um... Are you at all familiar with the type of heavy duty welded aluminum
boats the poster inquired about?

For example:

http://www.precisionweldboats.com/

http://www.weldcraftmarine.com/

http://www.duckworthboats.com/

http://www.roguejet.com/

http://www.customweld.com/

http://www.thunderjet.com/

http://www.motionmarine.com/

http://www.hewescraft.com/

http://www.fish-rite.com/boats.html

http://www.northriverboats.com/

etc.

As to the original question I'm no welding expert but I did examine a lot
of boats before buying one. I liked the neat consistency and smoothness
found in the North River and many others with a few notable exceptions
(this was 8 years ago). I've had some major rock hits since then and only
required one repair for a crack at the jet-pump intake seam. The .25"
bottom thickness helps.

I do see a lot Hewescraft on the Columbia river lately for what it's
worth.

0.25 on the bottom, don't have to worry about hull damage if you park in a
mess of logs. Going to take a look at Hewescraft.

"Canuck57" wrote in message
news:R6vij.61672$EA5.53484@pd7urf2no...

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...

wrote in message
...

First, rivets are used on aircraft for the following reasons, not all of
value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.

I think aluminum welds are fine as long as they are reinforced or the
sheets are relatively thick. Thin sheet (seam) welding of aluminum is
prone to cracking when subjected to even a little flex as compared to
other metals. Maybe someone with knowledge of metallurgy can explain the
crystalline structure, etc. My opinion is based on experience in
industry.

BTW, I think flex is much more important in airplane wings than you give
it credit for. Next time you fly, note the location of a wing tip as the
airplane begins it's take-off run and watch it as you become airborne.
While flying in turbulence, watch the tip of the wing again. There's
quite a bit of wobbling around going on out there. Welded aluminum
panels wouldn't last long, nor would the wings if they were designed to
be stiff rather than being allowed to flex.

Eisboch

But my point being, do you want that much flex on a 17-19' boat?

I would think not. But on an aircraft, this is good. The wings are in
effect shock absorbers for up/down drafts and air density changes. But I
don't think this level of flex is needed nor desirable on a small boat.


The wings of an aircraft are *not* designed to be shock absorbers. They may
be, by default of their ability to bend without breaking, but that's not the
design purpose. The design purpose is to allow them to bend and flex (which
they are going to do, welded or riveted) without breaking off. Rivets allow
the bending and flexing without exceeding the yield of the aluminum.
Welding would make them so stiff that they would snap near the welds.

But, that's not the issue. It's the fact that even a small, thin skinned
aluminum boat *will* want to flex. If it can't (because the seams are
welded) it's likely that one or more of the relatively weak welds will break
whereas a riveted construction allows the bending or flex without damage.

Even large, welded steel ships have expansion joints built into the hull
structure to allow for flexing, otherwise it would crack in half in rough
seas.

Eisboch

"Canuck57" wrote in message
news:yhvij.61683$EA5.61072@pd7urf2no...

"-rick-" wrote in message
news
Short Wave Sportfishing wrote:

Riveted aluminum boats tend to be sounder than welded boats and as a
general rule, easier to repair. The better aluminum boats, like Lund,
Starcraft, Princecraft, are riveted boats.

Um... Are you at all familiar with the type of heavy duty welded aluminum
boats the poster inquired about?

For example:

http://www.precisionweldboats.com/

http://www.weldcraftmarine.com/

http://www.duckworthboats.com/

http://www.roguejet.com/

http://www.customweld.com/

http://www.thunderjet.com/

http://www.motionmarine.com/

http://www.hewescraft.com/

http://www.fish-rite.com/boats.html

http://www.northriverboats.com/

etc.

As to the original question I'm no welding expert but I did examine a lot
of boats before buying one. I liked the neat consistency and smoothness
found in the North River and many others with a few notable exceptions
(this was 8 years ago). I've had some major rock hits since then and only
required one repair for a crack at the jet-pump intake seam. The .25"
bottom thickness helps.

I do see a lot Hewescraft on the Columbia river lately for what it's
worth.

0.25 on the bottom, don't have to worry about hull damage if you park in a
mess of logs. Going to take a look at Hewescraft.


Actually the 3/16 does logs fine.

"Calif Bill" wrote in message
...

"Canuck57" wrote in message
news:yhvij.61683$EA5.61072@pd7urf2no...

"-rick-" wrote in message
news
Short Wave Sportfishing wrote:

Riveted aluminum boats tend to be sounder than welded boats and as a
general rule, easier to repair. The better aluminum boats, like Lund,
Starcraft, Princecraft, are riveted boats.

Um... Are you at all familiar with the type of heavy duty welded
aluminum boats the poster inquired about?

For example:

http://www.precisionweldboats.com/

http://www.weldcraftmarine.com/

http://www.duckworthboats.com/

http://www.roguejet.com/

http://www.customweld.com/

http://www.thunderjet.com/

http://www.motionmarine.com/

http://www.hewescraft.com/

http://www.fish-rite.com/boats.html

http://www.northriverboats.com/

etc.

As to the original question I'm no welding expert but I did examine a
lot of boats before buying one. I liked the neat consistency and
smoothness found in the North River and many others with a few notable
exceptions (this was 8 years ago). I've had some major rock hits since
then and only required one repair for a crack at the jet-pump intake
seam. The .25" bottom thickness helps.

I do see a lot Hewescraft on the Columbia river lately for what it's
worth.

0.25 on the bottom, don't have to worry about hull damage if you park in
a mess of logs. Going to take a look at Hewescraft.


Actually the 3/16 does logs fine.

Sure better than 0.090 or 0.100.

Went fishing once in a tin can on a lake in the middle of Wisconsin,
Tomahawk I think. Found a large bay, and said this water does not look
right and slowed down. I was right, found out later why too. In the winter
if it freezes they dump stumps and logs into it for bass and it would be
like a mine field if you hit that with much more than adrift speed.

Needless to say, I took the tin in and had a gas. Lost count on how many
small mouth bass I nailed that day. But you could hear the aluminium flex
when you tapped one.

A bad day fishing is better than a good day at work.

On Sun, 13 Jan 2008 16:50:29 -0500, "Eisboch" wrote:

Even large, welded steel ships have expansion joints built into the hull
structure to allow for flexing, otherwise it would crack in half in rough
seas.

I saw a documentary on the Britannic, sister ship to Titanic, about
this very thing.

One of the more interesting aspects of the Titanic sinking were the
expansion joints. According to the documentary, the type of joint
used on the Titanic contributed to the diaster - I can't remember all
the technical details at the moment, but it was a type of joint that
was a "floating" joint. After the diaster, the Britannic was modified
to eliminate the the "floating" joint in favor of a boxed type joint.

Oddly, that type of joint contributed to Britannic's sinking when it
struck a mine off Greece in WWI.

It was pretty interesting.

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:R6vij.61672$EA5.53484@pd7urf2no...

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...

wrote in message
...

First, rivets are used on aircraft for the following reasons, not all
of value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.

I think aluminum welds are fine as long as they are reinforced or the
sheets are relatively thick. Thin sheet (seam) welding of aluminum is
prone to cracking when subjected to even a little flex as compared to
other metals. Maybe someone with knowledge of metallurgy can explain the
crystalline structure, etc. My opinion is based on experience in
industry.

BTW, I think flex is much more important in airplane wings than you give
it credit for. Next time you fly, note the location of a wing tip as
the airplane begins it's take-off run and watch it as you become
airborne. While flying in turbulence, watch the tip of the wing again.
There's quite a bit of wobbling around going on out there. Welded
aluminum panels wouldn't last long, nor would the wings if they were
designed to be stiff rather than being allowed to flex.

Eisboch

But my point being, do you want that much flex on a 17-19' boat?

I would think not. But on an aircraft, this is good. The wings are in
effect shock absorbers for up/down drafts and air density changes. But I
don't think this level of flex is needed nor desirable on a small boat.


The wings of an aircraft are *not* designed to be shock absorbers. They
may be, by default of their ability to bend without breaking, but that's
not the design purpose. The design purpose is to allow them to bend and
flex (which they are going to do, welded or riveted) without breaking off.
Rivets allow the bending and flexing without exceeding the yield of the
aluminum. Welding would make them so stiff that they would snap near the
welds.

But, that's not the issue. It's the fact that even a small, thin skinned
aluminum boat *will* want to flex. If it can't (because the seams are
welded) it's likely that one or more of the relatively weak welds will
break whereas a riveted construction allows the bending or flex without
damage.

Even large, welded steel ships have expansion joints built into the hull
structure to allow for flexing, otherwise it would crack in half in rough
seas.

Eisboch

While I don't profess to be an aircraft engineer, I done believe the sales
hype about boats are better because we build then like aircraft. The needs
of the two are different. Even the rivets are different.

You mean like Edmund Fitzgerald? Me, I don't plan on being in anything
remotely as hazardous as Lake Superior and have no intention of amidships
being over a 35' wave. Michigan, no problem. Koocanusa, Lake of the Woods,
Rainy River, nice. But I just have a thing about Superior...used to live by
that lake and I would sooner hit the Pacific.

But how much does a 17-20' boat need to flex? If we look at fibreglass in
this size, not much hull flex at all.

"Canuck57" wrote in message
news:wrwij.1919$wx.1785@pd7urf1no...

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:R6vij.61672$EA5.53484@pd7urf2no...

"Eisboch" wrote in message
...

"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...

wrote in message
...

First, rivets are used on aircraft for the following reasons, not all
of value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.

I think aluminum welds are fine as long as they are reinforced or the
sheets are relatively thick. Thin sheet (seam) welding of aluminum is
prone to cracking when subjected to even a little flex as compared to
other metals. Maybe someone with knowledge of metallurgy can explain
the crystalline structure, etc. My opinion is based on experience in
industry.

BTW, I think flex is much more important in airplane wings than you
give it credit for. Next time you fly, note the location of a wing tip
as the airplane begins it's take-off run and watch it as you become
airborne. While flying in turbulence, watch the tip of the wing again.
There's quite a bit of wobbling around going on out there. Welded
aluminum panels wouldn't last long, nor would the wings if they were
designed to be stiff rather than being allowed to flex.

Eisboch

But my point being, do you want that much flex on a 17-19' boat?

I would think not. But on an aircraft, this is good. The wings are in
effect shock absorbers for up/down drafts and air density changes. But
I don't think this level of flex is needed nor desirable on a small
boat.


The wings of an aircraft are *not* designed to be shock absorbers. They
may be, by default of their ability to bend without breaking, but that's
not the design purpose. The design purpose is to allow them to bend and
flex (which they are going to do, welded or riveted) without breaking
off. Rivets allow the bending and flexing without exceeding the yield of
the aluminum. Welding would make them so stiff that they would snap near
the welds.

But, that's not the issue. It's the fact that even a small, thin skinned
aluminum boat *will* want to flex. If it can't (because the seams are
welded) it's likely that one or more of the relatively weak welds will
break whereas a riveted construction allows the bending or flex without
damage.

Even large, welded steel ships have expansion joints built into the hull
structure to allow for flexing, otherwise it would crack in half in rough
seas.

Eisboch

While I don't profess to be an aircraft engineer, I done believe the sales
hype about boats are better because we build then like aircraft. The
needs of the two are different. Even the rivets are different.

You mean like Edmund Fitzgerald? Me, I don't plan on being in anything
remotely as hazardous as Lake Superior and have no intention of amidships
being over a 35' wave. Michigan, no problem. Koocanusa, Lake of the
Woods, Rainy River, nice. But I just have a thing about Superior...used
to live by that lake and I would sooner hit the Pacific.

But how much does a 17-20' boat need to flex? If we look at fibreglass in
this size, not much hull flex at all.


For some boats, the rigors of trailering on awful roads might be worse than
the pounding they get in the water.

Canuck57 wrote:
"Eisboch" wrote in message
...
"Canuck57" wrote in message
news:R6vij.61672$EA5.53484@pd7urf2no...
"Eisboch" wrote in message
...
"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...
wrote in message
...

First, rivets are used on aircraft for the following reasons, not all
of value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.
I think aluminum welds are fine as long as they are reinforced or the
sheets are relatively thick. Thin sheet (seam) welding of aluminum is
prone to cracking when subjected to even a little flex as compared to
other metals. Maybe someone with knowledge of metallurgy can explain the
crystalline structure, etc. My opinion is based on experience in
industry.

BTW, I think flex is much more important in airplane wings than you give
it credit for. Next time you fly, note the location of a wing tip as
the airplane begins it's take-off run and watch it as you become
airborne. While flying in turbulence, watch the tip of the wing again.
There's quite a bit of wobbling around going on out there. Welded
aluminum panels wouldn't last long, nor would the wings if they were
designed to be stiff rather than being allowed to flex.

Eisboch
But my point being, do you want that much flex on a 17-19' boat?

I would think not. But on an aircraft, this is good. The wings are in
effect shock absorbers for up/down drafts and air density changes. But I
don't think this level of flex is needed nor desirable on a small boat.

The wings of an aircraft are *not* designed to be shock absorbers. They
may be, by default of their ability to bend without breaking, but that's
not the design purpose. The design purpose is to allow them to bend and
flex (which they are going to do, welded or riveted) without breaking off.
Rivets allow the bending and flexing without exceeding the yield of the
aluminum. Welding would make them so stiff that they would snap near the
welds.

But, that's not the issue. It's the fact that even a small, thin skinned
aluminum boat *will* want to flex. If it can't (because the seams are
welded) it's likely that one or more of the relatively weak welds will
break whereas a riveted construction allows the bending or flex without
damage.

Even large, welded steel ships have expansion joints built into the hull
structure to allow for flexing, otherwise it would crack in half in rough
seas.

Eisboch

While I don't profess to be an aircraft engineer, I done believe the sales
hype about boats are better because we build then like aircraft. The needs
of the two are different. Even the rivets are different.

You mean like Edmund Fitzgerald? Me, I don't plan on being in anything
remotely as hazardous as Lake Superior and have no intention of amidships
being over a 35' wave. Michigan, no problem. Koocanusa, Lake of the Woods,
Rainy River, nice. But I just have a thing about Superior...used to live by
that lake and I would sooner hit the Pacific.

But how much does a 17-20' boat need to flex? If we look at fibreglass in
this size, not much hull flex at all.


If you can push in the sides of a typical sal****er fiberglass boat of
that length with your palm, then you have found junk.