Flotation foam

[Armedmariner]

Question 1:
I'm confused. People sell 4lb, 8lb and 16lb flotation foam. I have no idea what this means. Can anyone help me decipher this?

Question 2:
How can you determine the minimum needs for flotation? Do I need to install enough flotation to float the boat's full up weight? What is the Coast Guard minimum? Where can I find Coast Guard rules?

Question 3:
This stuff seems pretty expensive at Jamestown Distributors. Is there a cheaper source/alternative?

Thanks for your help as usual.

[Armedmariner]

Question 1:
I'm confused. People sell 4lb, 8lb and 16lb flotation foam. I have no idea what this means. Can anyone help me decipher this?

Question 2:
How can you determine the minimum needs for flotation? Do I need to install enough flotation to float the boat's full up weight? What is the Coast Guard minimum? Where can I find Coast Guard rules?

Question 3:
This stuff seems pretty expensive at Jamestown Distributors. Is there a cheaper source/alternative?

Thanks for your help as usual.

[Armedmariner]

Question 1:
I'm confused. People sell 4lb, 8lb and 16lb flotation foam. I have no idea what this means. Can anyone help me decipher this?

Question 2:
How can you determine the minimum needs for flotation? Do I need to install enough flotation to float the boat's full up weight? What is the Coast Guard minimum? Where can I find Coast Guard rules?

Question 3:
This stuff seems pretty expensive at Jamestown Distributors. Is there a cheaper source/alternative?

Thanks for your help as usual.

[stan v]

2lb is standard flotation. 16lb is more structural. Try this www.fgci.com (http://www.fgci.com)

[stan v]

2lb is standard flotation. 16lb is more structural. Try this www.fgci.com (http://www.fgci.com)

[stan v]

2lb is standard flotation. 16lb is more structural. Try this www.fgci.com (http://www.fgci.com)

[ahp]

This is a wild idea, and I welcome remarks. What about polystyrene foam board insulation? It is closed cell, and you can buy in big sheets, at least two inches thick, at Home Depot, cheap!

Cement it to the inside of the hull or the underside of the deck.

The flotation will be about the volumn (cubic feet) that is immersed x 62.5 pounds, less the weight of the foam, which is practically nothing.

[ahp]

This is a wild idea, and I welcome remarks. What about polystyrene foam board insulation? It is closed cell, and you can buy in big sheets, at least two inches thick, at Home Depot, cheap!

Cement it to the inside of the hull or the underside of the deck.

The flotation will be about the volumn (cubic feet) that is immersed x 62.5 pounds, less the weight of the foam, which is practically nothing.

[ahp]

This is a wild idea, and I welcome remarks. What about polystyrene foam board insulation? It is closed cell, and you can buy in big sheets, at least two inches thick, at Home Depot, cheap!

Cement it to the inside of the hull or the underside of the deck.

The flotation will be about the volumn (cubic feet) that is immersed x 62.5 pounds, less the weight of the foam, which is practically nothing.

[jlapratt]

I had fun working on Wednesday with the two part foam from FGCI. For floatation you want to use the lightest foam, 2 lbs/ft3. This gives you ~60 pounds floatation per ft3. As a thumb rule, take the weight of the parts of the boat that won't float (motor, accessories, battery & PEOPLE) and divide by 60. This gives you the cubic feet of foam needed to keep the boat from sinking when swamped. Please refer to the coast guard guide for accurate calculation and requirements for level floatation.

The FGCI stuff worked very well. I used 5 quarts resulting in ~10 ft3 and it cost $70.

[ 01-24-2003, 09:12 PM: Message edited by: jlapratt ]

[jlapratt]

I had fun working on Wednesday with the two part foam from FGCI. For floatation you want to use the lightest foam, 2 lbs/ft3. This gives you ~60 pounds floatation per ft3. As a thumb rule, take the weight of the parts of the boat that won't float (motor, accessories, battery & PEOPLE) and divide by 60. This gives you the cubic feet of foam needed to keep the boat from sinking when swamped. Please refer to the coast guard guide for accurate calculation and requirements for level floatation.

The FGCI stuff worked very well. I used 5 quarts resulting in ~10 ft3 and it cost $70.

[ 01-24-2003, 09:12 PM: Message edited by: jlapratt ]

[jlapratt]

I had fun working on Wednesday with the two part foam from FGCI. For floatation you want to use the lightest foam, 2 lbs/ft3. This gives you ~60 pounds floatation per ft3. As a thumb rule, take the weight of the parts of the boat that won't float (motor, accessories, battery & PEOPLE) and divide by 60. This gives you the cubic feet of foam needed to keep the boat from sinking when swamped. Please refer to the coast guard guide for accurate calculation and requirements for level floatation.

The FGCI stuff worked very well. I used 5 quarts resulting in ~10 ft3 and it cost $70.

[ 01-24-2003, 09:12 PM: Message edited by: jlapratt ]

[Walcheren]

This subject is close to my heart. I learned lots from a thread in the building and repair section under "buoyancy questions". There you will find most answers to your questions, I think. I used styrofoam used in roof insulation under the stern seat, under the floor boards,( 2" above the keel), in the thwart and in the bow. I suggest you go metric and measure everything in centimeters which will give you liters and a liter is 2 pounds plus ten percent. Etcetera. Do a search for "flotation" in the building and repair section and you will find lots of useful info.Dirk

[Walcheren]

This subject is close to my heart. I learned lots from a thread in the building and repair section under "buoyancy questions". There you will find most answers to your questions, I think. I used styrofoam used in roof insulation under the stern seat, under the floor boards,( 2" above the keel), in the thwart and in the bow. I suggest you go metric and measure everything in centimeters which will give you liters and a liter is 2 pounds plus ten percent. Etcetera. Do a search for "flotation" in the building and repair section and you will find lots of useful info.Dirk

[Walcheren]

This subject is close to my heart. I learned lots from a thread in the building and repair section under "buoyancy questions". There you will find most answers to your questions, I think. I used styrofoam used in roof insulation under the stern seat, under the floor boards,( 2" above the keel), in the thwart and in the bow. I suggest you go metric and measure everything in centimeters which will give you liters and a liter is 2 pounds plus ten percent. Etcetera. Do a search for "flotation" in the building and repair section and you will find lots of useful info.Dirk

[Tom Lathrop]

Search for the USCG on google and order a copy of their Safety Guides for Backyard Boatbuilders.

Most of the poured foams are not waterproof.

The blue styrofoam mentioned is waterproof and cheap. If it is to be in the bilge it should be coated with epoxy as a guard against attack by gasoline.

The CG booklet will give guidelines on required floatation but if there is room you could add a lot more.

[Tom Lathrop]

Search for the USCG on google and order a copy of their Safety Guides for Backyard Boatbuilders.

Most of the poured foams are not waterproof.

The blue styrofoam mentioned is waterproof and cheap. If it is to be in the bilge it should be coated with epoxy as a guard against attack by gasoline.

The CG booklet will give guidelines on required floatation but if there is room you could add a lot more.

[Tom Lathrop]

Search for the USCG on google and order a copy of their Safety Guides for Backyard Boatbuilders.

Most of the poured foams are not waterproof.

The blue styrofoam mentioned is waterproof and cheap. If it is to be in the bilge it should be coated with epoxy as a guard against attack by gasoline.

The CG booklet will give guidelines on required floatation but if there is room you could add a lot more.

[Wayne Jeffers]

Question 1: The designation 2 lb., 4 lb., etc., refers to the weight per cubic foot of the cured foam.

Question 2: Do what Tom says and get a copy of the CG guidance. You will find the USCG very helpful. Note that you need to consider the amount of flotation and the proper placement of the flotation so that the boat floats high, right-side-up, and level when swamped. The CG information covers this well. Get the book!

Question 3: The blue foam mentioned above is not only cheaper, it has another big advantage. You can install it so that you can remove it when necessary to air out the space it is occupying.

Another choice that I have generally come to prefer instead of foam is to build in flotation tanks with vents that can be opened for drying things out.

Wayne

[ 01-27-2003, 10:08 AM: Message edited by: Wayne Jeffers ]

[Wayne Jeffers]

Question 1: The designation 2 lb., 4 lb., etc., refers to the weight per cubic foot of the cured foam.

Question 2: Do what Tom says and get a copy of the CG guidance. You will find the USCG very helpful. Note that you need to consider the amount of flotation and the proper placement of the flotation so that the boat floats high, right-side-up, and level when swamped. The CG information covers this well. Get the book!

Question 3: The blue foam mentioned above is not only cheaper, it has another big advantage. You can install it so that you can remove it when necessary to air out the space it is occupying.

Another choice that I have generally come to prefer instead of foam is to build in flotation tanks with vents that can be opened for drying things out.

Wayne

[ 01-27-2003, 10:08 AM: Message edited by: Wayne Jeffers ]

[Wayne Jeffers]

Question 1: The designation 2 lb., 4 lb., etc., refers to the weight per cubic foot of the cured foam.

Question 2: Do what Tom says and get a copy of the CG guidance. You will find the USCG very helpful. Note that you need to consider the amount of flotation and the proper placement of the flotation so that the boat floats high, right-side-up, and level when swamped. The CG information covers this well. Get the book!

Question 3: The blue foam mentioned above is not only cheaper, it has another big advantage. You can install it so that you can remove it when necessary to air out the space it is occupying.

Another choice that I have generally come to prefer instead of foam is to build in flotation tanks with vents that can be opened for drying things out.

Wayne

[ 01-27-2003, 10:08 AM: Message edited by: Wayne Jeffers ]