What buoyancy foam do you guys use in the hull?

[Keencraftsman]

First post in this forum so hey guys. 
As the title says I’m looking for the exact foam guys are using in their boats so I can get some ordered for a boat I’m building. 
I am working on a 16’ CNC kit boat and it calls for buoyancy foam. I have been reading up on the coast guard regulations for boats under 20’ and I see it doesn’t have to be foam in particular but I don’t want to put ping pong balls water bottles or pool noodles in there. 

Last thing I have is that I don’t want to use a 2 part pour foam I want foam in sheets of some sort. That way I can pack it in and rest it on top of the stringers and keep it off the hull. 

So hoping you guys can basically say I use this foam from this company it’s what you need here is a link. I know it sounds like I want the easy route but I have been doing a lot of research and have learned quite a bit I just don’t want to get hundreds of dollars of the wrong stuff and have it adding hundreds or pounds to the hull or turning to slime. 

Thanks, looking forward to what you have to say 

[gandrfab]

I'm not a fan of foam and would also like to know the best option when it is required.

[Craigb]

Where are you located? There are a few different suppliers of the right foams. I am also not a fan, and would rather design and build boats over 20ft to get past the foam issue. There is an ASTM standard it has to meet now, to not soak up gasoline, oil, water etc, much better than the foams used in the past but adds a fair bit of cost and limits the layout of the boat as you need certain volumes based around the CG of the swamped boat, with a certain amount of load capacity(people) assumed to be hanging off one side.

[kmorin]

keen'man, hey!  Welcome to the ABB.com Forum.

I have to agree with the others who aren't fans of foam, and like craigb usually keep my work to 20'LOA or more to avoid it. Not that I'm building much these days!  I have several rants (masquerading as posts on various threads, here) about why foam is 'dumb', non-logical and downright foolish, but hey!  It's the 'gommint's regull-ation' so logic, reason and common sense (or engineering) aren't always the strong suit of that organization.

If there is a good solution? it would a fine service if you'll share what you learn while researching the topic since so few good methods exist.  I think I recall that Pacific (Black Lab?) used to actually make casting forms/molds that would result in blocks of foam that could fit into their structural longs and x-verse framing?  If I recall (and that's getting less clear as we go along) they used a polystyrene foam as it was pretty rigid, didn't absorb water and sealed its own surface when cast into a mold?  All that is my impression of a memory of reading a post on a thread here?  (search function)

Might call some of the builders who make plate/welded alum. boats and ask? All they can do is refuse to answer- not too poor an outcome.  Also, you might see if there are bulk plastics/foam distribution in your area? These people would likely be informed of their products' performance and applications??  If there is a foam that will meet the ASTM standards craig mentions (!) it would be good to learn about it.

The labor of fitting the open framing volumes with layers of sheet material sounds like a huge undertaking to me? Maybe with a portable hot wire table where you could cut fast and a skiff mounted on a rotisserie to make the access to all the compartments agile?  ...  you might be able to do the work in a 'reasonable' amount of time?  I'd prefer to watch the resulting video sped up to 3x speed than do all that work myself!

In the meantime, I'm sticking with my " sealed pressurized, hydrogen-filled, structural box-beam supports that can't be vented" when discussing the level flotation with any Coasties who want to waste time with my skiffs.

Please consider sharing your level flotation w/ foam education with the Forum. Thanks for posting.

Cheers,
Kevin Morin
Kenai, AK

 

[THE 26 JETTYWOLF]

quote ''''''I think I recall that Pacific (Black Lab?) used to actually make casting forms/molds that would result in blocks of foam that could fit into their structural longs and x-verse framing?''''''

NO. I believe my boat (26' Pacific. all Blacklab marine boats are built by Pacific in WA. Just were re-named for us ''right coasters'')  like 90% have spaces where foam is injected below deck, expands and thats it.

On the fence right now about foam injection in a new boat build...... ALL FOR SOUND DEADENING PURPOSES ONLY.

But cost is 2 GRAND!!!!! ON A 20 FOOTER.       crazy expensive in my book.

can also go block foam, but leary about foam versus just plain AIR.  and just live with the tinkling water sounds. and put 2k into a trolling motor instead.

maybe off your topic. but hell, haven't commented in months. need to help the algorythem 
  
 

[kmorin]

Captain Dave, AAB Forum readers,  keenscraftsman, anyone reading the thread.....
I decided to "Ask Julie" the Oracle of Pacific Skiffs about the foam they've used in their boats, as I was "almost sure" that I'd read they had (at one time) cast blocks to fit their structure?  Julie confirms that Captain Dave is totally correct. Julie very graciously took time to reply to a random email and let me know:

" The foam has always been a 2-part injected closed cell foam, never "cast blocks". The foam is USCG compliant and widely used by other boat manufacturers."-Julie from Pacific Skills.

Julie has spoken and No One can offer more insight: Pacific does NOT cast blocks to fill voids, they use a two-part foam injected into the voids that are filled with foam.

My Thanks to Julie with Pacific Skiffs, and Capt. Dave for the correction. 

I remain convinced that 'pressurized, hydrogen-filled, structural beam, voids' are the best practice... but (!!) that's only one vote for no-foam filled spaces in welded aluminum boat builds compared to 'gommint reggggul-ations'.

Captain Dave, you should post more often, if time allows.

Cheers,
Kevin Morin
Kenai, AK
 

[m32825]

I have no "sealed pressurized, hydrogen-filled, structural box-beam supports that can't be vented" but wouldn't helium be better from a flammability point of view?
 

[Keencraftsman]

Thanks for the replies and keeping the post going.
If I could go back and design for air chambers or buy a 20' boat I would do that but for this one I will be entering into make it happen territory.

I think I will call a couple manufacturers just to see if they will help out a bit, then when I have a little more time I will add a longer post with some more of the details from my research

[gandrfab]

Thank you for the update.

[THE 26 JETTYWOLF]

well there's those Aussie boats with no foam and they're kind of loud. even stabicraft is adding foam now. the two-part injected type. I believe.

with my new boat build I think I'm going to skip the foam.  for me it comes all down to the dollar amount. 

there is a hard foam that is being used because the builder of my boat said injection or block foam. or nothing.
it is pressurized sealed below the deck with two to four pounds. but they say that pretty much just the check for leaks.

my next boat's going to be 20 ft flat bottom. pretty much for shallow water fishing. I just hope it's not going to be too noisy.

 

[No Control]

Well,

Short answer, polyethylene. Used a lot in packing stuff, like refrigerators. Can also. be found in pool noodles.

I wouldn't use any spray in foam.
Though it is CG approved and labeled "Closed Cell". It is not water proof and can break down and soak up a considerable amount of water. I contacted two manufacturers and both confirmed it is not waterproof. It should be banned.

I pulled 3 to 4 hundred lbs of soaked foam from my 20 foot boat. It had started to corrode the hull and fuel tank.

Below is a link to a video. Life proof boats. Go to the 15 minute and 21:30 minute mark. He explains what they are using and why.

The "pillows" are available for purchase. Different sizes. They have garbage bags full of ground up foam (about 1 inch ) pieces. Probably give you that.
You could weigh it to determine how much to use and just pack into spaces under the floor or??

They are in Bremerton.
I went up and He gave me some large chunks of leftover from cutting ribs.

Life Proof boats. Ask ?For Micah, great guy.

I believe there is one type of foam insulation board that is both waterproof and chemically resistant? Dont remember the name. I tested a piece of the pink stuff and it melted with fuel contact.

Hoping to build a boat coming up. Will have self bailing floor and those bags underneath.

https://www.youtube.com/watch?v=rSf7U7aOCK4

[gandrfab]

Welcome, thanks for posting.