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Steel hull and aluminum superstructure



 
 
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  #11  
Old October 3rd 06, 08:15 PM posted to rec.boats.building
Pete C
external usenet poster
 
Posts: 41
Default Steel hull and aluminum superstructure

On Tue, 03 Oct 2006 07:50:54 -0400, Michael Porter
wrote:

"datacouple" is actually "dEtacouple" and is very much still around
and used by everyone in that business. take a look at
http://www.dynamicmaterials.com/

It seems that ownership of the product has bounced around some, but it
is still available. Now, how an individual can buy it -- that's
another story.

Cheers,

Michael


I like their NASDAQ ticker symbol: BOOM!

cheers,
Pete.
Ads
  #12  
Old October 3rd 06, 08:42 PM posted to rec.boats.building
Roger Long
external usenet poster
 
Posts: 172
Default Steel hull and aluminum superstructure

Oh, hello neighbor. I didn't realize you hung around these joints

--

Roger Long



"Michael Porter" wrote in message
...
"datacouple" is actually "dEtacouple" and is very much still around
and used by everyone in that business. take a look at
http://www.dynamicmaterials.com/

It seems that ownership of the product has bounced around some, but
it
is still available. Now, how an individual can buy it -- that's
another story.

Cheers,

Michael



  #13  
Old October 3rd 06, 09:41 PM posted to rec.boats.building
André Langevin
external usenet poster
 
Posts: 25
Default Steel hull and aluminum superstructure

From 2 $ in Nov 05 to about 31 $ today... it is much more like a supersonic
BANG


"Pete C" wrote in message
...
On Tue, 03 Oct 2006 07:50:54 -0400, Michael Porter
wrote:

"datacouple" is actually "dEtacouple" and is very much still around
and used by everyone in that business. take a look at
http://www.dynamicmaterials.com/

It seems that ownership of the product has bounced around some, but it
is still available. Now, how an individual can buy it -- that's
another story.

Cheers,

Michael


I like their NASDAQ ticker symbol: BOOM!

cheers,
Pete.



  #14  
Old October 4th 06, 03:42 AM posted to rec.boats.building
André Langevin
external usenet poster
 
Posts: 25
Default Steel hull and aluminum superstructure

Roger,

I'm still discussing with people at SPURIND and another company. I thought
of using a joint and it would work but what if lightning strike and i don't
have electrical connectivity between the superstructure and the hull ? The
mast could still be interconnected to the hull but it is a risk....

Better have electrical bonding between the two. i'm currently discussing
price, i'll post the findings.

cheers

"Roger Long" wrote in message
...
That is the stuff.

For homebuilding, I would just build a flatbar flange at the base of the
superstructure. Bolt and aluminum flatbar to it and then build the
aluminum superstructure on top. Unbolt after it's done, lift, and insert
a suitable gasket material. Then bolt it back on.

Being able to remove the superstructure would have a lot of advantages if
you had to do major repair on the interior.

Actually, I would build the whole boat out of aluminum. Stronger at the
same weight, more likely to deform in a way that stays watertight in event
of major damage, and easier to drill for temporary patches with hand or
battery powered tools. I'd much rather go up on a reef in a far away
place in an aluminum boat than a steel on unless the latter was large
enough to carry a full welding outfit.

Also, less compass issues with an aluminum boat.

--

Roger Long



"André Langevin" wrote in message
...
Very interesting Roger what you bring. As you said, i've searched also
in internet but there is not much reference. I will talk with a local
machinist also and keep you posted.

There is this company though: www.spurind.com but it might turn out
very costly since it seems to be a specialty.

André

"Roger Long" wrote in message
...
Sorry, but the following is completely wrong. The explosively jointed
bimetallic strips have a long and successful history. The aluminum is
welded to the aluminum side and the steel to the steel side. The strips
simply seem to have become hard to locate, at least via the web.

Regular steel and stainless steel are often joined. Problems can occur,
especially if submerged in salt water but you'll see mild steel /
stainless joints on fishing vessels that have been going for years and
years.

True, you can't weld aluminum directly to either.

How do I know about aluminum superstructure on a steel hull?

I did it on this boat:

http://www.bbsr.edu/About_BBSR/Facil...herbird_ii.htm

--

Roger Long



wrote in message
...
I have just double check with my friend who worked as a welder for 35
years in a shipyard that build commercial, coast guard vessels,
battleships and drilling platforms.
If you have an aluminums structure welding steel plates on or doing the
reverse was not in practice. Aluminums and mild steel or cold rolled
steel are not compatible. The same thing applies to welding stainless
steel. What takes place is a white inter granular corrosion that is
hardly visible to the naked eyes. Given time the white corrosion will
cause a structural failure. Not to mention the saline atmosphere at sea
that will accelerate the process.

"André Langevin" wrote in message
...
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as i'm
starting the construction of a new boat. I currently have a 34 feet
powerboat in aluminum and my nest boat will be a 44 or 45 steel
sailboat. I'm looking at building a Bruce Roberts design and i would
like the deck superstructure to be in aluminum. I've seen many
commercial boat done this way and even old Coast Guard patrol boat of
30+ years old without any corrosion problem so it is something i'd
like to do. But i can't find any industry that carries the special
strip that isolate both metals but still permit to weld them both.

Does someone ever see this ?

André











  #15  
Old October 4th 06, 04:44 AM posted to rec.boats.building
Evan Gatehouse2
external usenet poster
 
Posts: 54
Default Steel hull and aluminum superstructure

Roger Long wrote:
It used to be called "Datacouple". It's seems to have dropped off
Google's radar screen which essentially means non-existant now. The
only references I see are reviews of some old boats that use it.

It must still be around somewhere.


Detacouple or Deta-couple

Evan Gatehouse
  #16  
Old October 4th 06, 12:57 PM posted to rec.boats.building
Roger Long
external usenet poster
 
Posts: 172
Default Steel hull and aluminum superstructure

You would have plenty of electrical connection through the bolts.
They could be isolated but there would be little need to since they
would be inside and dry. You would probably want to use stainless
bolts anyway.

Even if you had the house isolated, lightning current would jump over
the small gap at the gasket like it wasn't even there.

The people wringing their hands over dissimilar metals forget that
stainless and aluminum are quite far apart but the millions of highly
stressed and critical stainless rigging fittings attached to the
millions of sailboat masts out there function for years and decades
without a problem.

--

Roger Long



"André Langevin" wrote in message
...
Roger,

I'm still discussing with people at SPURIND and another company. I
thought of using a joint and it would work but what if lightning
strike and i don't have electrical connectivity between the
superstructure and the hull ? The mast could still be
interconnected to the hull but it is a risk....

Better have electrical bonding between the two. i'm currently
discussing price, i'll post the findings.

cheers

"Roger Long" wrote in message
...
That is the stuff.

For homebuilding, I would just build a flatbar flange at the base
of the superstructure. Bolt and aluminum flatbar to it and then
build the aluminum superstructure on top. Unbolt after it's done,
lift, and insert a suitable gasket material. Then bolt it back on.

Being able to remove the superstructure would have a lot of
advantages if you had to do major repair on the interior.

Actually, I would build the whole boat out of aluminum. Stronger
at the same weight, more likely to deform in a way that stays
watertight in event of major damage, and easier to drill for
temporary patches with hand or battery powered tools. I'd much
rather go up on a reef in a far away place in an aluminum boat than
a steel on unless the latter was large enough to carry a full
welding outfit.

Also, less compass issues with an aluminum boat.

--

Roger Long



"André Langevin" wrote in message
...
Very interesting Roger what you bring. As you said, i've searched
also in internet but there is not much reference. I will talk
with a local machinist also and keep you posted.

There is this company though: www.spurind.com but it might turn
out very costly since it seems to be a specialty.

André

"Roger Long" wrote in message
...
Sorry, but the following is completely wrong. The explosively
jointed bimetallic strips have a long and successful history.
The aluminum is welded to the aluminum side and the steel to the
steel side. The strips simply seem to have become hard to locate,
at least via the web.

Regular steel and stainless steel are often joined. Problems can
occur, especially if submerged in salt water but you'll see mild
steel / stainless joints on fishing vessels that have been going
for years and years.

True, you can't weld aluminum directly to either.

How do I know about aluminum superstructure on a steel hull?

I did it on this boat:

http://www.bbsr.edu/About_BBSR/Facil...herbird_ii.htm

--

Roger Long



wrote in message
...
I have just double check with my friend who worked as a welder
for 35 years in a shipyard that build commercial, coast guard
vessels, battleships and drilling platforms.
If you have an aluminums structure welding steel plates on or
doing the reverse was not in practice. Aluminums and mild steel
or cold rolled steel are not compatible. The same thing applies
to welding stainless steel. What takes place is a white inter
granular corrosion that is hardly visible to the naked eyes.
Given time the white corrosion will cause a structural failure.
Not to mention the saline atmosphere at sea that will accelerate
the process.

"André Langevin" wrote in message
...
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as
i'm starting the construction of a new boat. I currently have
a 34 feet powerboat in aluminum and my nest boat will be a 44
or 45 steel sailboat. I'm looking at building a Bruce Roberts
design and i would like the deck superstructure to be in
aluminum. I've seen many commercial boat done this way and
even old Coast Guard patrol boat of 30+ years old without any
corrosion problem so it is something i'd like to do. But i
can't find any industry that carries the special strip that
isolate both metals but still permit to weld them both.

Does someone ever see this ?

André













  #17  
Old October 4th 06, 06:46 PM posted to rec.boats.building
max camirand
external usenet poster
 
Posts: 45
Default Steel hull and aluminum superstructure


André Langevin wrote:
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as i'm starting
the construction of a new boat. I currently have a 34 feet powerboat in
aluminum and my nest boat will be a 44 or 45 steel sailboat. I'm looking at
building a Bruce Roberts design and i would like the deck superstructure to
be in aluminum. I've seen many commercial boat done this way and even old
Coast Guard patrol boat of 30+ years old without any corrosion problem so it
is something i'd like to do. But i can't find any industry that carries the
special strip that isolate both metals but still permit to weld them both.

Does someone ever see this ?

André


There exist some bimetal strips that are used to join the steel to the
aluminium. Of course, you can't weld those two together.

If you want an aluminium superstructure because of its lower weight,
then maybe you could also consider a plywood deck and house.

-mc

  #18  
Old October 5th 06, 05:54 PM posted to rec.boats.building
André Langevin
external usenet poster
 
Posts: 25
Default Steel hull and aluminum superstructure

Hi Roger,

Here is the quote i've received. Indeed quite costly for an amateur. My
Roberts 43 would need at least 100 feet of this so about 6000 $ of material.

Item Qty Thickness Width Unit Price USD /lin ft Total Price USD
/item
1 12' 0.75 * 2" $62.13 $706.56


The more i think to your proposal the more it make sense. And it would but
my Roberts 43 to a very high level of stability given that i would save me
about 2000 pounds and the equivalent lever-arm since it is farm from the CG.
Another advantage is that it is so easy to keep the rust out of the hull but
much less on the decks since there is a lot of holes, fixtures and contact
with items like anchor, spi pole and so on.

It definitely need more reflection !

Thanks !


"Roger Long" wrote in message
...
You would have plenty of electrical connection through the bolts. They
could be isolated but there would be little need to since they would be
inside and dry. You would probably want to use stainless bolts anyway.

Even if you had the house isolated, lightning current would jump over the
small gap at the gasket like it wasn't even there.

The people wringing their hands over dissimilar metals forget that
stainless and aluminum are quite far apart but the millions of highly
stressed and critical stainless rigging fittings attached to the millions
of sailboat masts out there function for years and decades without a
problem.

--

Roger Long



"André Langevin" wrote in message
...
Roger,

I'm still discussing with people at SPURIND and another company. I
thought of using a joint and it would work but what if lightning strike
and i don't have electrical connectivity between the superstructure and
the hull ? The mast could still be interconnected to the hull but it is
a risk....

Better have electrical bonding between the two. i'm currently discussing
price, i'll post the findings.

cheers

"Roger Long" wrote in message
...
That is the stuff.

For homebuilding, I would just build a flatbar flange at the base of the
superstructure. Bolt and aluminum flatbar to it and then build the
aluminum superstructure on top. Unbolt after it's done, lift, and
insert a suitable gasket material. Then bolt it back on.

Being able to remove the superstructure would have a lot of advantages
if you had to do major repair on the interior.

Actually, I would build the whole boat out of aluminum. Stronger at the
same weight, more likely to deform in a way that stays watertight in
event of major damage, and easier to drill for temporary patches with
hand or battery powered tools. I'd much rather go up on a reef in a far
away place in an aluminum boat than a steel on unless the latter was
large enough to carry a full welding outfit.

Also, less compass issues with an aluminum boat.

--

Roger Long



"André Langevin" wrote in message
...
Very interesting Roger what you bring. As you said, i've searched also
in internet but there is not much reference. I will talk with a local
machinist also and keep you posted.

There is this company though: www.spurind.com but it might turn out
very costly since it seems to be a specialty.

André

"Roger Long" wrote in message
...
Sorry, but the following is completely wrong. The explosively jointed
bimetallic strips have a long and successful history. The aluminum is
welded to the aluminum side and the steel to the steel side. The
strips simply seem to have become hard to locate, at least via the
web.

Regular steel and stainless steel are often joined. Problems can
occur, especially if submerged in salt water but you'll see mild steel
/ stainless joints on fishing vessels that have been going for years
and years.

True, you can't weld aluminum directly to either.

How do I know about aluminum superstructure on a steel hull?

I did it on this boat:

http://www.bbsr.edu/About_BBSR/Facil...herbird_ii.htm

--

Roger Long



wrote in message
...
I have just double check with my friend who worked as a welder for 35
years in a shipyard that build commercial, coast guard vessels,
battleships and drilling platforms.
If you have an aluminums structure welding steel plates on or doing
the reverse was not in practice. Aluminums and mild steel or cold
rolled steel are not compatible. The same thing applies to welding
stainless steel. What takes place is a white inter granular corrosion
that is hardly visible to the naked eyes. Given time the white
corrosion will cause a structural failure. Not to mention the saline
atmosphere at sea that will accelerate the process.

"André Langevin" wrote in message
...
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as i'm
starting the construction of a new boat. I currently have a 34 feet
powerboat in aluminum and my nest boat will be a 44 or 45 steel
sailboat. I'm looking at building a Bruce Roberts design and i
would like the deck superstructure to be in aluminum. I've seen
many commercial boat done this way and even old Coast Guard patrol
boat of 30+ years old without any corrosion problem so it is
something i'd like to do. But i can't find any industry that
carries the special strip that isolate both metals but still permit
to weld them both.

Does someone ever see this ?

André















  #19  
Old October 5th 06, 09:35 PM posted to rec.boats.building
Roger Long
external usenet poster
 
Posts: 172
Default Steel hull and aluminum superstructure

If you are worried about rust, I would suggest making the deck of
aluminum as well as the cabin trunk and having the flange arranged at
the deck edge like a fiberglass boat. Any leaks that did develop
would then be out where they would most likely just run down the side
of the hull. The area under the cabin edge would be very clean and
easy to finish off. A bedded guard rail would protect the edge of the
gasket and keep water away from the area where two kinds of metal are
in close proximity.

The best thing of all would be the fact that sandblasted aluminum
plate without paint is an excellent non-skid surface.

--

Roger Long



"André Langevin" wrote in message
...
Hi Roger,

Here is the quote i've received. Indeed quite costly for an
amateur. My Roberts 43 would need at least 100 feet of this so
about 6000 $ of material.

Item Qty Thickness Width Unit Price USD /lin ft Total Price
USD /item
1 12' 0.75 * 2" $62.13 $706.56


The more i think to your proposal the more it make sense. And it
would but my Roberts 43 to a very high level of stability given that
i would save me about 2000 pounds and the equivalent lever-arm since
it is farm from the CG. Another advantage is that it is so easy to
keep the rust out of the hull but much less on the decks since there
is a lot of holes, fixtures and contact with items like anchor, spi
pole and so on.

It definitely need more reflection !

Thanks !


"Roger Long" wrote in message
...
You would have plenty of electrical connection through the bolts.
They could be isolated but there would be little need to since they
would be inside and dry. You would probably want to use stainless
bolts anyway.

Even if you had the house isolated, lightning current would jump
over the small gap at the gasket like it wasn't even there.

The people wringing their hands over dissimilar metals forget that
stainless and aluminum are quite far apart but the millions of
highly stressed and critical stainless rigging fittings attached to
the millions of sailboat masts out there function for years and
decades without a problem.

--

Roger Long



"André Langevin" wrote in message
...
Roger,

I'm still discussing with people at SPURIND and another company.
I thought of using a joint and it would work but what if lightning
strike and i don't have electrical connectivity between the
superstructure and the hull ? The mast could still be
interconnected to the hull but it is a risk....

Better have electrical bonding between the two. i'm currently
discussing price, i'll post the findings.

cheers

"Roger Long" wrote in message
...
That is the stuff.

For homebuilding, I would just build a flatbar flange at the base
of the superstructure. Bolt and aluminum flatbar to it and then
build the aluminum superstructure on top. Unbolt after it's
done, lift, and insert a suitable gasket material. Then bolt it
back on.

Being able to remove the superstructure would have a lot of
advantages if you had to do major repair on the interior.

Actually, I would build the whole boat out of aluminum. Stronger
at the same weight, more likely to deform in a way that stays
watertight in event of major damage, and easier to drill for
temporary patches with hand or battery powered tools. I'd much
rather go up on a reef in a far away place in an aluminum boat
than a steel on unless the latter was large enough to carry a
full welding outfit.

Also, less compass issues with an aluminum boat.

--

Roger Long



"André Langevin" wrote in message
...
Very interesting Roger what you bring. As you said, i've
searched also in internet but there is not much reference. I
will talk with a local machinist also and keep you posted.

There is this company though: www.spurind.com but it might
turn out very costly since it seems to be a specialty.

André

"Roger Long" wrote in message
...
Sorry, but the following is completely wrong. The explosively
jointed bimetallic strips have a long and successful history.
The aluminum is welded to the aluminum side and the steel to
the steel side. The strips simply seem to have become hard to
locate, at least via the web.

Regular steel and stainless steel are often joined. Problems
can occur, especially if submerged in salt water but you'll see
mild steel / stainless joints on fishing vessels that have been
going for years and years.

True, you can't weld aluminum directly to either.

How do I know about aluminum superstructure on a steel hull?

I did it on this boat:

http://www.bbsr.edu/About_BBSR/Facil...herbird_ii.htm

--

Roger Long



wrote in message
...
I have just double check with my friend who worked as a welder
for 35 years in a shipyard that build commercial, coast guard
vessels, battleships and drilling platforms.
If you have an aluminums structure welding steel plates on or
doing the reverse was not in practice. Aluminums and mild
steel or cold rolled steel are not compatible. The same thing
applies to welding stainless steel. What takes place is a
white inter granular corrosion that is hardly visible to the
naked eyes. Given time the white corrosion will cause a
structural failure. Not to mention the saline atmosphere at
sea that will accelerate the process.

"André Langevin" wrote in
message ...
Hi to all,

I am a newcomer on this newsgroup and you'll see me around as
i'm starting the construction of a new boat. I currently
have a 34 feet powerboat in aluminum and my nest boat will be
a 44 or 45 steel sailboat. I'm looking at building a Bruce
Roberts design and i would like the deck superstructure to be
in aluminum. I've seen many commercial boat done this way
and even old Coast Guard patrol boat of 30+ years old without
any corrosion problem so it is something i'd like to do. But
i can't find any industry that carries the special strip that
isolate both metals but still permit to weld them both.

Does someone ever see this ?

André

















  #20  
Old March 18th 13, 03:14 PM
Alumiman Alumiman is offline
Junior Member
 
First recorded activity by BoatBanter: Mar 2013
Posts: 1
Default

Quote:
Originally Posted by Pete C View Post
On Tue, 03 Oct 2006 07:50:54 -0400, Michael Porter
wrote:

"datacouple" is actually "dEtacouple" and is very much still around
and used by everyone in that business. take a look at
http://www.dynamicmaterials.com/

It seems that ownership of the product has bounced around some, but it
is still available. Now, how an individual can buy it -- that's
another story.

Cheers,

Michael


I like their NASDAQ ticker symbol: BOOM!

cheers,
Pete.
Anyone looking to buy some detacouple can find it at Aluminum & Stainless, Inc. in New Orleans LA. 504-586-9191
 




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