What foam can be use for bouyancy??????

Hi Iam thinking in put my Newport 27 unsinkable. My dream boat is the Heavenly Twins 27 and I read is unsinkable and even more can sail full of water. Ok thats the ???? What is the correct foam for that???? and how much????? the boat need to maintaince afloat even with the water on the deck.???????Need to be full closed and sealed "foam"??????? I know about 3m two part foam but I dont know how much bouyancy have. I lost a Herreshoff Eagle 1973 8 years ago the boat sunk in opoen sea in 110 feet of water. I spend $2000 looking for the boat and nothing appear. I still suffering that, and know Iam selling my Columbia 39 to keep the Newport and dont want to lost them. Please friends 4 easy ???? Thanks.

 

Anyone else??

 

Mario

I elieve you need to use a Closed Cell Poly Eurothane Foam, that is both high density (45Kg/m2 ??) AND fire retardent!

This not cheap.

The foam blocks must be Fibreglass encapsulated (or at the very least, heavey stable plastic wrapped and waterproff gaffa taped). This is because, the foam is very "crumbly" and with banging caused by waves - the foam crumbs will float on top of any water in the bilge - then they will block the screen on your bilge pump and likely burn out the bilge pump due to no water to lubricate / cool it, just when you need it most!

To alculate the amount is tricky, - you need to know the under deck ullage (volume) calculation (how much space in M3) to place foam blocks.

You also need to know vessels hull weight - weight of all machinery / plant and volume / weight of all fuel and freshwater tanks etc. Also weight of all usual stocks carried aboard (food etc etc). Lastly you need to know the number of people and their weight..

Now the Formulae is relatively simple - but don't ask me it because I can't remember.

You see, you must displace enough M3 of water - with the foam to be more than all the combined weights of the vessel - BUT it is not so easey as this - because - for Eg, fuel is actually lighter than water and so floats a little so you don't need to displace as much water as the fuel - only a certain %. Same with people...they are almost all fresh water...(98%)?....so you only need to displace enough water with foam to make up the difference and so on and so forth.

Someone here wil know the correct forumlae...and correct my "generalisation answer" for you I hope... My answer is close but not exact.

If you have computer plans for your vessel, likely it's designer can tell you under deck ullage (volume) figures for your vessel...and also help you work out the amount of water you must displace with foam - don't forget you have to include the weight of the foam as well in calculation!

Now - it's not enough just too - place foam under deck...

What if boat is stern heavey wth engines etc??? If vessel swamps, can you sit on pointy end (bow) for 3 days or a week until help arives? (ouchi wah wahh my backside feels like 1000 haemmeroids!)

So - you need to look at weight distribution in boat and place sufficient foam around LCB (longituudinal centre of bouyancy) so boat floats upright and level, while you wait for rescue - then only wet underpants give you crutch itch!...again ouchi wah wahhh, (maybe better to drown eh?

Cheers & good luck...

Pls excuse typing and ??? answer, today is "upside down land turkey day" and too much sun, too much fishing. too many sherbets after fishing...

More cheers! (hic!)

 

Hi everybody, again with this thread. Howard Huges the brilliant aviation engineered, my father toll me in his big dream when he make the most big airplane he make it with wood, but he filled the wings with pin pong balls, I don't remeber the exactly amount but was a lot of then. Thinking about this I ask my self humm this little plastic balls don't take water, long a lot of years, have a incredible flotation, they are very small and very lightweight. So now the ??????/// how many balls I will need to maintain the deck of my sailboat paralell with the water or maybe two or three feet below the water?? just that if the boat sunk I can still look at him, not to used like a raft for that I have my dinguis. I lost a Herreshoff Eagle 1971 8 years ago and the boat disappears from my eyes to the bottom of the sea. I don't want to this happen again. I now the clue is maintain everything in orther but hit rocks or containers or things out of your control can make your boat sink. So if anyone can make a some kind of formula to calculate this I will be gratefull. My boat disp 7000 pounds plus 1000 pounds more I added with people and equipment =8000 Total. Thanks

 

Actually, you can use anything that will float as bouyancy in case of flooding or swamping. Most people use polyurethane foam. However, I have seen just about everything imaginable, ping pong balls, beer cans, plastic bottles of various shapes and sizes, even those pool toys that look like long tube of foam. They are made of polyurethane by the way. You do not need to enclose or bag closed cell foam. However, if you use polystyrene ( styrofoam) it should be encapsulated or inside boxes. It is friable ( that is tends to come apart in little pieces) and also will be dissolved by cleaners, solvents, gasoline, other petroleum products, so it needs protection.

Take a look at my web site at the page on basic flotation. The example is a dinghy but it can be scaled up to anything http://members.aol.com/spinners/flot3.html

Or look at the Coast Guards site for the boat builders hand book. http://www.uscgboating.org/safety/boatbuilder/flotation_landing.htm

 

Hi: Ike, about foam tubes, I think one tube hold me the necesary to not needed to swim just paralell my head with the water. So my weight is 165, if I divide 8000 pounds / 165 pounds that holds one tube the = is 48.48 =49 foam tubes to hold my boat with the deck facing the water or just the necesary to not sink completly in the deep. I'am correct??? please reply's Thanks again Mario

 

http://www.shopmaninc.com/foam.html
Urethane foam. 2lb. density. "Narine grade (closed cell), not cheap household handyman stuff. You get what you pay for. After it's in, it's there for good.
When filling space, keep in mind to think before foaming around lines, wires or components that may have to be removed someday.
DO NOT fill anywhere that will stay wet or constantly damp. urethane is water resistant not waterproof. Keep it wet for extended periods and it turns into a heavy sponge..
Take your displacement (l X w X h X 62#) and you will have an idea of cubic feet of foam @ 60# bouyancy (average) per cu. Ft. you need.

 

If you use 2 lb density foam it will float 62.4 pounds in salt water and 60.4 in fresh water. However you don't need as much as you think. The reason is everything has a different weight in the water. People are right around neutral bouyancy so we use a factor of .125 to calculate the amount of foam that is needed
Persons weight (you 165 lbs) X .125 /60.4 ilbs/cu ft = .67 cu ft.
so round up to 1 cu ft of foam for yourself.

The same is true of other stuff. for instance if your boat is fiberglass and the fiberglass in the boat weighs 2000 ib

2000 lb X factor for FRP (.33) /60.4 = 11.11 Make it 11.5 for a safety margin

Say your engine weighs 300 lb. Since it is mostly metal and has no real buoyant factor so the factor is 1.
300/60.4 = 4.97 Round to five

One last example. There are things in your boat that float, like wood.

The factor for wood depends on the type of wood depending on how dense it is. for instance WHite Oak is fairly dense so the factor is -0.18. Plywood is not dense so the factor is -.81 These factors are negative because the material is buoyant but DOES HAVE WEIGHT.

For plywood. Assume you have 300 lbs of plywood in your boat
Then 300 X -0.81 / 60.4 = - 4 cu ft

After you figure out the amount of flotation for each catagory needed to float your boat you add up the cubic footage for each catagory.

Then that foam needs to be distributed in the boat to float in an upright attitude unless you just want it to float and don't care about the attitude of the boat.

 

Hi: Ike I will try that formula, and how sounds to you the foam tubes??Thanks

 

If it's good enough for Genmar it's good enough. On one of Genmar's boats they discovered they didn't have enough flotation (I can't remember which brand it was , Larson, Glastron, I don't remember) Anyway that is how they fixed it. They installed two of those foam tubes on each side of the boat under the gunwales. Worked like a champ!.

 

Just be warned that some of those "fun noodle" tube things are hollow in the middle, so be sure to check buoyancy empirically (in other words, sink them personally, rather than relying on calculations).

Also, be very careful to heed Ike's advice about buoyancy(?) factors. One "fun noodle" may float a 165lb human, but that's not the same as floating 165 pounds of steel... Humans will practically float all on their own- without assistance. So make some tests.

Also, from what I can tell, those commercial-type foam products are ridiculously overpriced as compared to what you'd pay for just a big piece of foam from a supplier. Your mileage may vary on that one though.

 

Hi: Thanks to both, thats true I never realize that human body have air in his interior vs a piece of steel or fiber. I will try in my dock with a anchor and check how many tubes I need vs the pounds of the steel anchor, thats is supose to work. I know we can figure out a cheap way to do this and have piece of mine when I sail on the darkness. I found on the web a supplier for this foam products. Thanks again

 

The factors I used are taken directly from both ABYC and Coast Guard tables used to calculate the amount of flotation required in boats under 20 feet in length. You should always provide a margin for safety. (a lot of manufacturers don't and they forget that production boats get heavier over a long production run because they keep adding stuff to the boats)

The big issues with providing more than you need are where do you put it? and what attitude is your boat going to be in when it pops to the surface? If you put it all in the bilge the boat will float nicely upside down. If it's all up in the bow, like on most inboards, the boat will float with the bow sticking out of the water and nothing else. So you have to think not only where can I put it, but also where should I put it. If you put it all under the deck on most production boats today, it will rip the deck mold off the hull. So think about it.

The fun noodles that genmar used were bought directly from the manufacturer and had no color in them, and were solid, not hollow. They did a special production run just for Genmar. I don't think they are going to do that for you. LOL.

 

whats with all the question marks ????????????????????????????????????

 

jajajajja you are funny jajajaja, if you take a look all my thread have the ???????? I do that for two reason first find my threads more easy and second to catch the attention of the people. Thanks for your ?? reply.