My New Old Boat - 1974 Seaswirl Cascade

[jbcurt00]

Deck (floor) details can be found here
http://forums.iboats.com/forum/boat...lamingo-splashed-w-pics?p=5550980#post5550980

Foam was for flotation, structure and quiet the sound of water against the hull, IMO all are possible, but I can live w out it for the last 2. Flotation would be my primary concern

Pour in foam is typically used for fiberglass boats, not sheet foam.

Store the boat well covered, bow high w the plug out and any water that gets below decks has a chance to get out before freeze thaw cycles rupture the foams cells and it becomes waterlogged.

Waterlogged foam doesnt happen overnight or because a little moisture got below decks.

 

[ericamity]

Thanks jbcurt. So do you have a foam product that you think would be best for this application? This boat will be garaged for the future. Thanks for your help.

 

[Woodonglass]

Several of our fiberglass boat members have in fact used the Pink or Blue slab foam in their boats. It works quite well. As for your stringers if you're convinced the stringers are still well attached to the hull and they do not contain a lot of water then I suppose you could leave them as is. The interior foam acted as the mold for the glass. The glass, IF applied thick enuf is what carries the structural load. My only problem in your case is that IF the MFG did NOT use multiple layers of glass OR at least two layers of 24 oz Woven Roving to provide the Bulk for the stinger then they poured the hull full of foam to stiffen it up and prevent flexing as well as add the needed flotation. Bottom line is this...It's your boat and you're free to do as you see fit. We're here to advise you about all the safety considerations and methods that should be considered. After that, you have to make the decisions and do the work.

 

[ericamity]

Hi Woodonglass . . . well, I'm thinking I will put the foam back in there . . . good for flotation, sound and structure. The stringers are quite solid and seem very able to handle the structural load . . . but given the manufacturer put foam in there I think I will do the same.

So do you have a link to the type of foam you're referring to? I can't get a picture in my mind of exactly what you're referring to. Are you talking about big blocks of foam that we have to carve to shape? My dad and I are a bit confused as to what product you're referring to and then how to get it to fit in the spot we have for it. Seems like there would be a lot of voids, etc. I also saw this in another post and it seems like he's saying the same thing as you. We just can't picture it.

All of the problems with water absorption have been with two part pour (or spray) foams. It appears it is all in the mixxing and application of the foam. It has to done within very narrow temperature and humidity ranges to foam up correctly.

In over thrirty years I have never seen a boat with block foam (that is premade foam) have water absorption problems. In fact we ran a two year test of block foams to see if they would soak and the most was 2/10% of the weight of the foam. That ain't a heck of a lot of water.

Do you recommend glassing over the wood flooring? Thanks so much for all the useful information that you've posted in this forum.

 

[jbcurt00]

Slab foam insulation from HomeDepot or Lowes. Pink or Blue

 

[ericamity]

Like this stuff? And how would you install it? Just stuff it under the floor? Glue it in? Sorry. If I'm asking too many questions, feel free to tell me to get lost!

Also, what about pool noodles like in this attached picture? Are pool noodles closed-cell foam?

 

[jbcurt00]

No pool noodles, they dont support weight like you'd think and arent closed cell. I can 'float' my 240lbs roughly on 1 noodle, but I'm neutrally buoyant, your boat isnt.

Although WoodOnGlass is correct, slab has been used on glass boat rebuilds, IMO pour in foam is more typical.

As I dont suggest it, I'll defer to him for installation methods. I will say it has to be cut to shape to basically fill the entire cavity you're putting it in, 100%.

Yes those are the insulation panels, your 1st pix is of a tin boat

 

[Woodonglass]

Uhmm, I'm gunna disagree with JBC on this one POOL NOODLES are Made from Closed Cell foam IMHO, but I DO agree they aren't the best thing to use for the job!!!! Never seen them used in a Glass boat. Typically the Blue or Pink Slab Foam is cut to fit and stood on edge and laid between the stringers in a Glass Boat so that it's level with the top of the stringers. this provides a LOT of support for the deck and at the same time gives ample flotation. I'll see if I can find some examples and post the links.

Well iBoats member RickRyder was the guy that I was thinking of but...His Thread with the pics appears to have issues. This links to his pics is either messed up or he has closed his IMGUR account. Pics no longer show up!!!! :grumpy:

This drawing may help you understand the stacked on edge concept.. The Brown Portions represent your stringers. The foam is Easily cut on a Tablesaw

 

[ericamity]

Is foam required? Do I really have to have it? I'm thinking of a few cross-stringers for structure . . . so we don't need the foam for the structure. Is there a legal requirement for flotation? I thought I read that in another thread but can't find it now.

 

[Woodonglass]

No, As a Home Boat builder you are under no legal obligation to place flotation foam under the deck. Having said that, not doing so, greatly reduces the safety factor of your boat. Any catastrophic failure and your boat can and will sink!!! That open's a whole different can of worms!!!! We always advise our members to err on the side of safety. But as previously stated, we can only State the advice. What you do with it is totally your choice.

 

[DeepBlue2010]

The simple answer you are looking for is NO. It is not required and you don't have to have it. Boat manufacturers however MUST comply with Coast Guard regulations which states that boats under certain overall length must have flotation foam. Now that the boat is out of factory and you are restoring it, the Coast Guard regulations do NOT apply to you.


With that said however, your desire to skip the foam to save few dollars has the potential of being an epic false economy that might end up costing you - multi fold down the road - of what are you trying to save now that is assuming, we hope and pray, that the loses will be just financial in nature.

To put this in perspective, if your boat - God forbid - started to take water and sunk, you are the one who is financially responsible for retrieving it from the bottom, pay all the associated cost (this is no easy hit) on top of the environmental cleaning fees associated with the fuel, oil and endangering marine life and disturbing the fish while they are trying to take a nap and whatever else they can throw at your face.

If your insurance are A-holes, they will find every possible way, no flotation foam included - to deny your claim for any assistance and you will find yourself on your own. I am not drawing a bleak picture here. These are realistic expectations and I am involved - professionally not personally - in some of these situations.

Long story short, while you don't have to foam your boat, I strongly encourage you to. It is a simple and cheap insurance policy.

I am not sure how the buoyancy of foam sheets from hardware or home improvements stores compares to the two part mix flotation foam usually used in boat building. I am not advocating for it or against it, I am just simply did not come across any information to compare between them at least from buoyancy stand point.

Not all foams created equal, the pourable 2 parts urethane comes in different weight ratings (2, 3, 4, 8, 16Ib) kits. These are the weight of fully expanded 1 cubic foot of the foam after you pour it and it cures. The buoyancy of one cubic foot actually decreases as you go up in weight but you gain on different other criteria. Take a loof at this chart for examples. You can see that one cubic foot of the 2Ib foam can keep 60Ib weight suspended. Can one cubic foot of the pink or blue foam do that, I simply don't know. The moral of the story is that, it is not just a matter of filling space with foam. You get the idea.

 

[ericamity]

I appreciate all the responses. I'm definitely going to put foam in the boat. The question is now, how much foam do I need to purchase? Some guy suggested I might need 2 or 3 cubic feet but I think that's crazy. The boat is 15 feet long and the space in the middle is at least 8 inches deep. Im thinking more like 10 cubic feet. I wonder if even that is enough to keep the boat afloat if it fills with water. These are all interesting facts you are bringing up to me and it makes the project more and more complicated. Ugh.

 

[DeepBlue2010]

I appreciate all the responses. I'm definitely going to put foam in the boat. The question is now, how much foam do I need to purchase? Some guy suggested I might need 2 or 3 cubic feet but I think that's crazy. The boat is 15 feet long and the space in the middle is at least 8 inches deep. Im thinking more like 10 cubic feet. I wonder if even that is enough to keep the boat afloat if it fills with water. These are all interesting facts you are bringing up to me and it makes the project more and more complicated. Ugh.

Do yourself a favor and stop listening to this guy. As this chart indicates, sorry I forgot to post it yesterday


one cubic foot (of the 2Ib kit) will sustain only 60Ib. You do the math.

 

[Woodonglass]

The Pink and Blue Slab foam has the same flotation properties as the 2lb pour in foam. I have a similar boat so, I'm pretty sure you're gunna need about 10 - 12 cubic ft. Measure the spaces between your stringers in inches and then plug the numbers into this...http://www.cascom.army.mil/cubicfeetininches.htm
That will tell you how much foam you can put below the deck and how much weight it will float.

 

[DeepBlue2010]

Even if the two has the same bouncy which i doubt, they don't have the same strength. The pink has 15 PSI compression strength while the 2Ib urethane has 40. You can select either one of them as you see fit for your application, just be aware of their differences and make an informed decision.

 

[Woodonglass]

Another added benefit of the pour in foam is that it does ad a bit of structural integrity to the boat due to the fact that it acts as a bit of Glue and attaches all components together. For your Job I'm Guess-Ti-Mating $150 bucks of Pour in foam to do the job. I'm thinking about the same cost for using the Pink Or Blue slab so as far as costs go it's a toss up. Just a matter of which way you wanna go for installation methods. Both are Tried and True methods.

 

[ericamity]

Thanks guys. I'm leaning toward the pour-in foam, for structural reasons. I'll take some pictures eventually as I go so you can see the progress. I really, really, really appreciate the advice. Nothing like a community of experts to help in the research process. Thanks again.

 

[ericamity]

No Title

OK. So we're installing the new floor now. We're putting it on top of the lip of fiberglass left around the edges. Adding plenty of glass underneath the lip to make sure it's plenty sturdy to support the new floor. Using Lloyds of London marine plywood (1/2"). Added three new stringers from side to side to enhance stability. See the one in the bow. Glassing all those in. Coating all the wood with resin. We're going to install a Beckson port (in the back in front of the well) to be able to look under the floor anytime and make sure that things are staying dry. Things are coming along. We will pour the expandable foam in soon (through some holes we'll cut in the floor. We'll plug the holes and then glass the entire floor in. Even without the foam or the fiberglass on the top, the floor already feels rock-solid.

 

[kcassells]

Keep asking questions and shooting pics. I'm not a tinny but I really like the boat. And at the end of the day pour foam is the best solution for your size boat. IMHO. The alternatives work also and most of the time it's a matter of budget for most. I think you'll be happy with the end result. What everyone is saying about the foam is that you do have options.

 

[ericamity]

Finally got this baby in the water. Still have more things to do but they're all little things to finish up.