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 02-08-2019, 08:34 AM
  #21  
Senior Member
 
Join Date: Jan 2018
Location: Texas
Posts: 300
Default

Originally Posted by tunnles View Post
American boats no wonder THE Chinese don't have many here ! they want boats that last !
Surprised it took you this long to start spitting out your bullshit.
txaggie25 is offline  
Old 02-08-2019, 09:44 AM
  #22  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 56
Default

Originally Posted by tunnles View Post
Foam is just foam and to try and use it as structural YOUR ANIDIOT !!
And the reason NEVER BUY A SECOND HAND BOAT !
Foam is a broad term for several materials that are used in many industries for structural purposes, including boat manufacturing. My questions is regarding this particular boat model. I am not trying add foam for structure, I have removed it and before I throw the new floor in I am making sure it is not required to stiffen the kevlar laminated structure. I have never worked on a kevlar hull, thus my doubt.

The three boats in my signature were all second hand bargain boats. Two of them have been properly restored and brought back to life . I have learned a lot by taking a hands on approach. This and other forums have contributed greatly when I have required information.

paler is offline  
Old 02-08-2019, 09:46 AM
  #23  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 56
Default

Originally Posted by Bullshipper View Post
If the sponsons were filled with 2 part expanding foam there is no doubt it stiffened the laminate more than just air would.
2-4 lb/ft3 is usually used for flotation, and 4 will be more resistant to water, chemical and fuel absorption
6# is what is used to to make wider bulk heads about 3 " thick
and you can find the 13# stuff if you want even more stiffness and strength.
So if you take it out, add some more mat to the rounded tunnel radius to beef it up and some on the bottom and other side too.
The deck is one thing, but the weight of the bottom on the trailer is also reinforced by what you want to remove so I would not cut deeper than box bottom depth on the bh in view of that.
Gotcha, thanks
paler is offline  
Old 02-08-2019, 09:57 AM
  #24  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 56
Default

Originally Posted by Kerry View Post
Kevlacats were never foam filled, foam in this case sounds like some meaningless bureaucratic misunderstanding
Thank you Kerry, this is good to know. I understand that in AUS people prefer the sealed deck with airtight bulkheads in these types of boats with very few or no inspection hatches

I will probably go foamless but will make limber holes in the bulkeads and run pumps. I will also include a couple of inspection hatches if I dont do the under floor storage. I feel more comfortable with pumps.

It is my impression that over the years, water will find its way into the sponsons.
paler is offline  
Old 02-08-2019, 09:59 AM
  #25  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 56
Default

Originally Posted by Bullshipper View Post
You will have to reinforce the thin gas tank bulkhead if no foam is replaced there.
Maybe I can replace the bulkhead with a rib or elbow like the panga below which would allow a box over it.



paler is offline  
Old 02-08-2019, 10:17 AM
  #26  
Senior Member
 
Join Date: Nov 2002
Location: Long Island, NY
Posts: 6,445
Default

I would contact the company that built the boat if they are still in business and ask them.
LouC is offline  
Old 02-08-2019, 11:50 AM
  #27  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Sep 2003
Location: CA & San Carlos, Mx
Posts: 20,221
Default

Originally Posted by paler View Post
Maybe I can replace the bulkhead with a rib or elbow like the panga below which would allow a box over it.


securing 400 lb gas tanks to something solid under decks is my concern. The foam
removed beefed up the thin one and backed it up to the thicker one close behind
Ntrain2k likes this.
Bullshipper is offline  
Old 02-08-2019, 11:53 AM
  #28  
Senior MemberCaptains Club MemberPLEDGER
 
Join Date: Sep 2003
Location: CA & San Carlos, Mx
Posts: 20,221
Default

Originally Posted by LouC View Post
I would contact the company that built the boat if they are still in business and ask them.
the floor board of the storage box can be fiberglassed to each inner side of the sponson
Bullshipper is offline  
Old 02-08-2019, 12:46 PM
  #29  
Member
Thread Starter
 
Join Date: Oct 2012
Location: Republic of Panama
Posts: 56
Default

Originally Posted by Bullshipper View Post

the floor board of the storage box can be fiberglassed to each inner side of the sponson
gotcha, kind of a horizontal bulkhead ... good idea
paler is offline  
Old 02-08-2019, 01:18 PM
  #30  
Senior Member
 
Join Date: Apr 2015
Posts: 786
Default

Originally Posted by tunnles View Post
If YOU HAVE TO RELY ON FOAM FOR STRUCTUAL INTEGRITY THEN YOUR IN TROUBLE AND DONT UNDERSTAND BOATS AND BOATING !
did you fall and bump your head? foam is used all the time for structural components, especially composites.

Last edited by pilotwerxs; 02-10-2019 at 07:08 AM.
pilotwerxs is offline  
Old 02-08-2019, 02:09 PM
  #31  
Senior Member
 
Join Date: Mar 2016
Posts: 152
Default

Originally Posted by tunnles View Post
Foam is just foam and to try and use it as structural YOUR ANIDIOT !!
And the reason NEVER BUY A SECOND HAND BOAT !
*you’re an Idiot. At least do it right if you plan on insulting someone who is simply asking a question.
Badmako is offline  
Old 02-08-2019, 02:44 PM
  #32  
Junior Member
 
Join Date: Feb 2019
Posts: 2
Default From personal experience

My friend has small fishing boat he did not buy. It was awashed ashore. it was submerged but not sunk because all cavities are filled with foam. He sails it at any weather because he knows it will not sink. One time after the storm we wanted to go fishing and saw little fountain of water coming through the hole on the bottom of the hull. We went anyway. After some time fountain stopped. Evidently water filled some cavity an expanded the foam somehow and it sealed the hole.
Marat is offline  
Old 02-08-2019, 05:16 PM
  #33  
Senior Member
 
Join Date: Jan 2011
Location: Northern Burbs of the Motor City
Posts: 5,980
Default

Originally Posted by Marat View Post
My friend has small fishing boat he did not buy. It was awashed ashore. it was submerged but not sunk because all cavities are filled with foam. He sails it at any weather because he knows it will not sink. One time after the storm we wanted to go fishing and saw little fountain of water coming through the hole on the bottom of the hull. We went anyway. After some time fountain stopped. Evidently water filled some cavity an expanded the foam somehow and it sealed the hole.
oh
magua is offline  
Old 02-08-2019, 05:19 PM
  #34  
Admirals Club Admiral's Club Member
 
Join Date: Mar 2016
Location: Under the sun
Posts: 682
Default

Originally Posted by Marat View Post
My friend has small fishing boat he did not buy. It was awashed ashore. it was submerged but not sunk because all cavities are filled with foam. He sails it at any weather because he knows it will not sink. One time after the storm we wanted to go fishing and saw little fountain of water coming through the hole on the bottom of the hull. We went anyway. After some time fountain stopped. Evidently water filled some cavity an expanded the foam somehow and it sealed the hole.
I wonder if your friend also sprays resins without any protective gear or respirator...
combi_40 is offline  
Old 02-08-2019, 05:23 PM
  #35  
efx
Senior Member
 
Join Date: Jan 2017
Posts: 241
Default

is tunnles a lot slow? maybe foam in the head?
efx is offline  
Old 02-08-2019, 05:30 PM
  #36  
Junior Member
 
Join Date: Feb 2019
Posts: 2
Default

Originally Posted by combi_40 View Post
I wonder if your friend also sprays resins without any protective gear or respirator...
In fact he does not wear the mask...he said that when you are 80 years old it does not matter...though lately he started to wear wetsuit when going out fishing in inclement weather...
Marat is offline  
Old 02-08-2019, 05:40 PM
  #37  
Senior Member
 
Join Date: May 2004
Location:
Posts: 156
Default

Originally Posted by tunnles View Post
American boats no wonder THE Chinese don't have many here ! they want boats that last !
Do they call it "roar roam" over there? Its well known in US how well engineered and long lasting oriental products are.
raptor660 is offline  
Old 02-08-2019, 10:10 PM
  #38  
Senior Member
 
Join Date: Oct 2015
Location: Texas
Posts: 639
Default

Curious as to how many foam haters have actually poured and worked any. Even 2 lb urethane material is tougher than human skin. I do recognize counterpoints about water retention in confined spaces but foam is most definitely structural in just about any application and if you think otherwise you're probably a dumbass.
efx likes this.
Sharpest is offline  
Old 02-08-2019, 11:52 PM
  #39  
Senior Member
 
Join Date: Feb 2004
Posts: 848
Default

I don't believe the Kevlar cats when built in oz used foam as a structuall nature however a lot of cats especially shark-cats cut blocks of foam to the internal shape of the sponson leaving about 50 mil for water flow to the transom this foam was sealed and only allowed a very small amount of water in the hull even on impact and a hole in the hull I would recommend this in any void you have it is really displacement
ozmako is offline  
Old 02-09-2019, 12:54 AM
  #40  
Senior Member
 
Join Date: Jan 2007
Location: NSW Australia
Posts: 4,108
Default

The foam in Sharkcat was just polystyrene, most are water logged, but unless you cut the floor out, you will never know, I have done three, and they were all the same, blocks cut roughly to size, and all had water in them, remember they haven't been made for decades.
noelm is offline  

Thread Tools
Search this Thread