Flotation Foam

[nsdave]

Hello. I'm new to your forum and wanted to ask about what seems to be a fairly common topic, flotation foam. I have a 16-1/2 foot runabout. I'd like to add some flotation to counter the weight of the outboard motor and battery. The boat, being a 1930's design, was never designed with added flotation in mind and I'm wondering if anyone has any experience with a flexible sheet foam?

I have seen a product called Ethafoam 221 on Dow's website. It's primarily a packaging foam but also appears to have UL approval for flotation service. Unfortunately, it only seems to be available in thin sheets (1/2 inch or so). Ideally, I'd like to find something 3 or 4 inches thick. Using flexible foam would enable me to fit it easily under floor boards and along the curved hull, between the frames.

I'm not very interested in pourable foam (I really don't want anything to bond to the hull).

Rigid foam would require a lot of cutting and fitting because of the hull curvature.

My thinking is that the softer foam would also add a bit of sound damping, which I wouldn't mind.

Also, being able to remove the foam somewhat easily to check that moisture isn't being trapped would be a plus.

I've seen lots of flotation ideas in the various forums but the unfortunate thing these days is the approval that's needed. Personally, I think using those swimming pool 'noodles' would have a lot of possibilities but without some bureaucratic OK I'd be wasting my time, unfortunately.

If any of you folks out there have used a product that you could recommend, I'd really appreciate hearing from you.

Thanks,
Dave

[Todd Bradshaw]

You can buy ethafoam (polyethylene foam) up to 4" thick from places like this if you can afford it ('cause it's pretty pricy):
http://www.foamorder.com/closedcell.html

You can also buy 2" ethafoam and minicell foam from the repair item listings of Northwest River Supplies:
http://www.nrsweb.com/shop/product_list.asp?deptid=1091
(scroll down to near the page bottom)

These foams will add some flotation, but are probably less efficient at it than some of the lighter, stiffer strofoam types. Even so, I doubt they will be heavy enough up in the bow to offset the weight of a motor and battery in the stern to any real degree. I'd also be willing to bet that if you're shooting for some kind of official approval for the stuff, the regulations most likely require some sort of serious attachment to the hull (like glue). This doesn't mean that you can't add it for your own benefit, but if it's in there to meet an official flotation specification, the government often seems to take a dim view of removable safety equipment.

Ethafoam has pretty decent long-term durability, especially if you keep it out of the sun. There are also some high-flotation upholstry cushion foams available, in case that's an option.

[ 02-15-2005, 05:22 AM: Message edited by: Todd Bradshaw ]

[santone]

Closed cell foam mat may be found at http://www.marinefoam.com Go to "closed cell foam" in the marine products section. It's the 1" X 48" X 72" @ 74.00 per sheet. This is sufficiently flexible to be shaped into curved areas such as the bilge, bow and stern.
The flotation blocks, 20" X48"X 7", may be found at http://www.amistorefront.com/SearchResult.aspx?CategoryID=48
We used 2 blocks at $49 each to provide flotation in our 13 1/2" Rhodes designed Woodpussy shown on my sailing site http://24.47.49.176:8000/sailingworld/
Regards, Tony

[Paul Scheuer]

Closed cell foam blocks are being used more and more in packaging of pricey electronic equipment and appliances. For some reason dark blue seems to be a popular color. You might see if you can make a connetion to some receiving docks where they throw the stuff away. The stuff I see is flexible enough to use in PFDs and car top pads. (Not soft enough for seat pads).

I'm not sure what the best cutting, shaping method might be. Maybe a hot knife or wire.

[whb]

If you line your cavity with some shape following material (plastic sheeting) you may be able to pour in liquid flotation foam to get a perfect fit that is still removable.

Howard

[nsdave]

Thanks a lot for the feedback. I'll check out a few of those sources.
Using the pourable foam along with some sort of a barrier or liner is an interesting possibility. I haven't used this sort of product before and I have seen a lot of comments regarding the heat that's generated, but I suppose if it's done in small batches it should be manageable.
Guess I'd better get to work....thanks again.

[imported_Dutch]

make sure what ever you get is close celled and wont melt in gasoline

[Leon m]

Originally posted by whb:
liquid flotation foam .

HowardAnybody know more about this stuff,Is it good stuff,where can you buy it ,is it light or heavy?

[Bob Cleek]

"I'd like to add some flotation to counter the weight of the outboard motor and battery."

HELLO? Adding foam floatation inside a boat is NOT going to reduce its displacement one iota. (Obviously, adding it to the bow isn't going to measureably affect trim either.) If the engine and battery are putting her below her lines aft, they are too heavy. (Moving the battery forward might help a bit though.)

A lot of baloney seems to be thrown about regarding floatation. Aside from dinghys that are dumped regularly, foam floatation in a wooden boat is pretty pointless in my book. Better to put your efforts towards keeping the boat afloat than trying to make it float after she's sunk. If you must, use air chambers. A simple bulkhead forward with a gasketed hatch (an off the self item) will provide plenty of bouyancy and storage as well. Or, just stick and inner tube under the thwart and pump it up.

Call me a crotchety old fart, but if you are that worried about keeping your boat afloat, maybe boats aren't your sport. How about skydiving?

[ 02-20-2005, 04:41 AM: Message edited by: Bob Cleek ]

[Dave Carnell]

Bear in mind that the water absorption values of all foams are for only 24hr. In long-term exposure, they all pick up much more, which is why you see SUNFISH that weigh a ton and foam-filled fiberglass boats way heavier than their production weights.

Any foam flotation has to be kept dry to be effective.

[ssor]

NSDave, You still haven't answered the basic question ,"is the boat out of trim because of the weight of the motor and battery?"

[Ellis Rowe]

Ditto on the foam. I know from bitter experience it's a bad idea. I've heard of guys using soda bottles, probably best to put the caps on. When I was a kid I had a scheme to raise the Titanic by pumping her full of ping pong balls. I wonder if there would be a cheap source for factory second ping pong balls. Maybe some come through their manufacturing process out of balance or malformed in some way that wouldn't preclude their use for flotation. Anyhow, as others have pointed out they would only increase flotation if you fill the boat with water, which I can't recommend.

[nsdave]

Well, there have certainly been a few interesting responses.
When I mentioned the motor and battery I was simply trying to convey that I needed to bear these in mind when locating the flotation.
In the interests of brevity let's just forget that I even mentioned the motor and battery. My question was essentially that of trying to solicit some opinion on flotation foam. The simple fact of the matter is that approved flotation is a modern day requirement in order to have my boat licensed.
I must say that it's a bit disappointing to encounter the sort of response that Mr Cleek provides, but life's too short to worry about it.

I think I've heard all that I need.....thanks.

[ion barnes]

I think I know what you are driving at Dave. I am assuming you are wanting to apply for a Capacity Plate? Hence you are concerned with the hull floating once it has been swamped. Yes, you need a volume that equates to the weight of the back end of the boat when loaded with people and gear. Canadian standards use something like 130lbs per person and 120 something pounds for a 20hp motor and portable fuel tank.

This my suggestion: Put the hull on a 2x6 plank, under the transom with a couple of bathroom scales equal distances from the center line and one scale under the bow. Note the weight with the equvalent weight in the boat for the #of people expected, add the two at the stern and you have a theroetical weight you want to support when swamped. Ditto for the bow. If either weight is greater than the scale, add another scale and a plank. What you are trying to do is estimate the weight distribution in your boat under normal conditions.

[ssor]

OH my! Such detail would have avoided much searching for meaning in an arcane question. USCG requirements for open boats are quite plain, they must float on an even keel when swamped.
Ion Barnes solution seems clear enough. Add one cu.ft. of secured foam for each sixty pounds of gross weight of vessel when loaded.

[nsdave]

Thanks for the helpful suggestion Ion. I'm in the process of sourcing the foam (Ethafoam) now.

[ion barnes]

Personally, I would not spend much on the foam. Anything that floats is good enough, just keep it suspended ubove the bilge and it wont get soggy.

Really, I think this thing about water sucking foam is rather overblown. I have sprayed-in foam in my Bayliner and the boat is almost 30 years old and the foam is dry as toast. I have a little punt that had cheap foam blocks under the seats, and it got left out over the winter full of water, its ok too, so the whole idea is a bit skeewed. Its there for a reason and as someone has already said, how many times are you going to swamp it? Its an insurance policy.

[ 02-21-2005, 02:12 PM: Message edited by: ion barnes ]

[ion barnes]

And and why are persons calculated at 130lbs?

Ans: You weigh less in the water hence the rating on your PFD, It only has to make you float, not stand up. And, 130lbs is the average of the group of people onboard. Yourself, significant other, and two friends divided by 4 equals ?

Thats one reason why you hear of so many boats sinking because two guys go to the stern to help start the engine and the boat cannot support all the extra weight.

[ 02-21-2005, 02:24 PM: Message edited by: ion barnes ]

[ssor]

Even battleships have been capsized when the crew displayed all of the ships cannon shells on deck. A little common sense goes a long way.

[Gary E]

I must say that it's a bit disappointing to encounter the sort of response that Mr Cleek provides, but life's too short to worry about it.
Well, get ready to get another volly lobed at ya..CUZ Mr Cleek is 100000% right...Ifin you cant or wont make sure your boat is not fit for the purpose intended, spend some money on life jackets and a whistle. Better yet, dont go out in water deepern your belt buckle.

I have never seen such weenies with this goofy idea that a boat should provide a fail safe method of floating. I have had alum boats of about the same size and we had NO floatation, a big engine and a built in gas tank 30 or so gals capacity along with two of the normal 6 gal standard tanks. We also had one other thing, INSPECTION of ALL areas of the boat so as to keep it in GOOD WORKING ORDER. That boat took us to more places in very sloppy water and broght us home every time.

I agree with Mr Cleek, maybe you best rent a boat, that way it's not your problem.

Rant over
G

[Leon m]

Originally posted by Gary E:
[QUOTE] ...Ifin you cant or wont make sure your boat is not fit for the purpose intended, spend some money on life jackets and a whistle. Better yet, dont go out in water deepern your belt buckle.

GHmmmm wonder what the boys of the Edmund Fitzgerald would think about that.

Fact is bad weather happens ..."better safe than sorry".

If the foam aint hurting nobody why not.

[Mike Vogdes]

Dave,
Welcome to the WBF...

Mr Cleek is a crotchety old fart sometimes but atleast he throws out some good ideas along with his verbal bitch slapping.

When I was a kid we had a duster sailboat that had partially inflated tire tubes stuffed under the for and aft decks, fortunatly we never dunked the boat so they were never tested, but it was reasuring they were there.

I guess I'm just another weenie who believes in the goofy idea of a fail safe method of floating.

[BillyBudd]

Cleek's response seems okay by me amd I'm writing in support of his comments. Some can be abrasive, usually because there's a thought (it seems) that such will awaken the respondent to a clearer boat-world view. Call it Zen dock talk. I can recall many years ago asking a similar question about flotation because, with grandchildren to take out, in the event of a knock down something that'll float a bit higher than sea level was thought useful and reassuring. My approach is the inflatable inner tube, fore and aft, one each. Pump up before, deflate afterward...no concern about foam/glue/wood surface horror shows with moisture, etc. Keep on Cleek, there are many, aye many!, who appreciate you. Say, for skydiving, do you think an inflatable suit would cushion the impact on landing? :D

[mmd]

With the greatest of respect to Mr. Cleek's opinion (whom I think very highly of), and to those whom have expressed agreement in his position, I offer the following as defense for nsdave's enquiry:

From the 2004 edition of Transport Canada's Construction Standards for Small Vessels:

4.2.7.1.1 - This sub-section applies to all power-driven small vessels not over 6 m (19 feet 8 inches) in length that are subject to swamping.

4.2.7.2.1 - Every small vessel shall be fitted with inherently buoyant floatation material that provides sufficient buoyancy to keep the vessel from sinking when it is swamped and when the passengers are clinging to the outside of the vessel...

Give him a break, guys; he is trying to comply with the law of the land and when he asks for our supposedly sage advice, he gets jeered and called a coward.

Has the odour from the bilge permeated so high in the ship?

[Paulyboy]

Originally posted by Bob Cleek:
"I'd like to add some flotation to counter the weight of the outboard motor and battery."

HELLO? Adding foam floatation inside a boat is NOT going to reduce its displacement one iota. (Obviously, adding it to the bow isn't going to measureably affect trim either.) If the engine and battery are putting her below her lines aft, they are too heavy. (Moving the battery forward might help a bit though.)

A lot of baloney seems to be thrown about regarding floatation.

Call me a crotchety old fart, but if you are that worried about keeping your boat afloat, maybe boats aren't your sport. How about skydiving?So, can we surmise the same as to skydiving? A lot of baloney seems to be going around about whether to use a parachute or not. I, myself, would rather stay in the plane, but maybe some people would rather fall out of one. :eek: :rolleyes: :eek:

[ssor]

Canadian and US requirements appear to be quite the same. Just because the boat is swamped you don't want it to sink A few cu.ft. of foam under the seats won't get in anybody's way and just might save a life.
My 30FT full keel sloop would sink like a stone if completely flooded, which is why I built in water tight compartments fore and aft.