Go Back  The Hull Truth - Boating and Fishing Forum > BOATING FORUMS > The Boating Forum
Reload this Page >

Does foam contribute to structural integrity on catamaran hull?

Notices
Like Tree56Likes

Does foam contribute to structural integrity on catamaran hull?

Old 02-13-2019, 05:28 AM
  #101  
Senior Member
 
Join Date: Nov 2015
Location: Jax FL
Posts: 2,304
Default

Originally Posted by OReely View Post
Since you apparently consider yourself an "eggspurt", or at least type like you are, I'm curious, just how many boats have you built? How many have you repaired? How many have you designed? Engineered?

There is more that one way to skin a cat, or in this case, build one. To dismiss urethane foam out of hand is not all that complementary to your expressed knowledge.
Pouring foam in a hull cat or not is stupid any way you slice it. Only an attempt to cover poor engineering and try to stupid proof cheap construction. Eventually foam will waterlog. That could not happen if it were truly closed cell. If you think 18" of that crap improves you little dingy then by all means pour to your hearts content. OPs hull will have no poured foam. OPs brand if hull has no tunnel cracks. OPs question answered. The proof is out there in the purchase price of one of these foam filled POS disposable craft. Is there a place for them? Sure there is. Rotting in your back yard in case you ever get that dream machine.
Jumpsummo is offline  
Old 02-13-2019, 07:03 AM
  #102  
Senior Member
 
Join Date: Feb 2007
Location: North Palm Beach, FL
Posts: 8,460
Default

Originally Posted by Jumpsummo View Post
Pouring foam in a hull cat or not is stupid any way you slice it. Only an attempt to cover poor engineering and try to stupid proof cheap construction. Eventually foam will waterlog. That could not happen if it were truly closed cell. If you think 18" of that crap improves you little dingy then by all means pour to your hearts content. OPs hull will have no poured foam. OPs brand if hull has no tunnel cracks. OPs question answered. The proof is out there in the purchase price of one of these foam filled POS disposable craft. Is there a place for them? Sure there is. Rotting in your back yard in case you ever get that dream machine.
So, from your response, I'll have to assume that the answers to my questions are none, none, none, and none.

I agree, urethane foam can have failures as you've stated but, while there may be instances of poor engineering or making for cheap construction, the vast majority of boats built have sound engineering behind them. Not every hull needs to be or should be filled with foam. I never made a claim otherwise. Some builders do it for flotation only, some use it a structural member, some do it for both. Just because you find fault doesn't mean it's not a viable use of the material.
OReely is offline  
Old 02-13-2019, 07:34 AM
  #103  
Senior Member
 
Join Date: Nov 2015
Location: Jax FL
Posts: 2,304
Default

Not CAN fail. WILL fail. Will waterlog. It's only a matter of time. Once again: Please fill YOUR should you ever buy one, favorite POS with foam to your hearts content. I draw the line at letting you advise others to do so.
Jumpsummo is offline  
Old 02-13-2019, 08:33 AM
  #104  
Senior MemberCaptains Club Member
 
Join Date: Nov 2008
Location: Southeast Alaska
Posts: 5,876
Default

Regulations in the United States do not required flotation in a hull over 20 feet in length, no regulation requires drain plugs and and such. If drain plugs and bilge pumps are installed they are likely there for damage control.
Unlike some others responding to this thread, I have designed and built boats , have over 40 years in the industry and have a very good understanding of what foam can and cannot do.
I'm done with this thread, any chance of logic and informed discussion has sailed.
Gerald
commuter boats is offline  
Old 02-13-2019, 09:07 AM
  #105  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 57
Default

Originally Posted by noelm View Post
To get back to the boat that this thread is actually about, his boat does not need foam for structural strength, it probably does /did contribute some, but, that's not his problem, he wants to remove a bulkhead, let's forget about how strong foam is or isn't, the bulkheads are there for a reason in that boat, and it's not to hold the floor up, I think it could be removed if the storage "box" that was built into the space was properly constructed and glassed in, but it's an educated risk that only the owner can say whether he is willing to take.
Amen brotha!
paler is offline  
Old 02-13-2019, 09:19 AM
  #106  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 57
Default

Getting back on track, I have concluded that I do not need foam for structural purposes on this particula hull. I am going to laminate over some sections where I believe the hull could/should be a little beefier.

Ran some numbers and if I were to use foam for flotation purposes I would need about 65 ft³ of #4 pour in foam. That would take up almost all the space beneath floor to achieve neutral flotation, even the area taken up by the big fuel tanks.

I will install 2 1100 GPH bilge pumps per sponson with high water alarms and garboard/drain plugs on the transom beneath the pods. I am keeping all existing bulkheads and opening limber holes to drain properly.

Thank you for all the contributions to this thread.
Bullshipper likes this.

Last edited by paler; 02-13-2019 at 09:20 AM. Reason: typo
paler is offline  
Old 02-13-2019, 06:08 PM
  #107  
Senior Member
 
Join Date: Feb 2007
Location: North Palm Beach, FL
Posts: 8,460
Default

Originally Posted by Jumpsummo View Post
Not CAN fail. WILL fail. Will waterlog. It's only a matter of time. Once again: Please fill YOUR should you ever buy one, favorite POS with foam to your hearts content. I draw the line at letting you advise others to do so.
You draw the line? At the risk of crossing that line in the sand, please point me to the post where I said to fill it with foam. I haven't advised anyone to use foam (not that your oh so scary line would stop me).The fact of the matter is early in this thread I suggested that the OP may be able to use frames in place of the foam to get away from possible issues of inadequate structure if the foam was removed. I even went so far as to suggest a material for him to look at to build the framing. What, pray tell, have you suggested?

Another fact is that urethane foams can and are used as structural members. That is all I said about foam as it relates to this thread. You may not like that fact but there it is.

And just to entertain you a bit more, I built my "POS" and it is not filled with foam. Neither are the nearly 600 other "POS" I built.
OReely is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread