I have an older fiberglass sailboat, I know some of the new sailboats have floatation foam in the event a boat takes on water, has anyone installed foam in their boat to prevent a lead keeled boat from plunging to the bottom? If so how'd ya do it? Thanks, Biff
Foam Floatation
- Thread starter Before the Bell
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do not know what boat you have
But- imho its not something that is reasonable to do on most boats. getting the quality of foam you need that wont absorb water is a very hard thing to do after the fact. Installing foam in a boat is not for the faint of heart. the expanding foam and distort hulls, break decks. blow out bulkheads and so on. The foam is very critical as to mixture with exactly mix time, and quantities of a two part mix. If the temperture is no just perfect for the mix and the mix time you get a totally unsatifactory job that wont resist obsorbing water. The foam is nasty to work with very hard to get off anything it touches The amount of foam has to be calculated based on the weight you want to float. Putting in the foam takes special tools and technique. as the foam goes in it stars to expand instantly blocking the holes you pour it thru. think about a 5-gal can of gooey sticky liquid that is trying to triple its volume in a few moments. If you screw up youd be cleaning for 6 months and trying to refinish the interrior. If you got it in and it was not in the right place the boat could float one end up or sideways or even upside down. Buy a raft.
But- imho its not something that is reasonable to do on most boats. getting the quality of foam you need that wont absorb water is a very hard thing to do after the fact. Installing foam in a boat is not for the faint of heart. the expanding foam and distort hulls, break decks. blow out bulkheads and so on. The foam is very critical as to mixture with exactly mix time, and quantities of a two part mix. If the temperture is no just perfect for the mix and the mix time you get a totally unsatifactory job that wont resist obsorbing water. The foam is nasty to work with very hard to get off anything it touches The amount of foam has to be calculated based on the weight you want to float. Putting in the foam takes special tools and technique. as the foam goes in it stars to expand instantly blocking the holes you pour it thru. think about a 5-gal can of gooey sticky liquid that is trying to triple its volume in a few moments. If you screw up youd be cleaning for 6 months and trying to refinish the interrior. If you got it in and it was not in the right place the boat could float one end up or sideways or even upside down. Buy a raft.
The math is against you
Ed Macs do use factory installed blocks of foam to create bouyancy in the event of a catastrophe. BUT... they are either swing keels or water ballasted boats ... a full lead keel is MUCH heavier. Let's just consider the keel, ignore for the moment, the weight of the hull and the difference in density of salt water and fresh water. One cubic foot of water weighs 62+ pounds. To raise a 700 lb weight (my keel) it would take 12 cubic feet of air. To raise a 7,000 keel it would take 113 cubic feet. I'm willing to bet that you're not willing to give up that much cabin space. Like my Daddy said. "Liars can figure, but figures don't lie" So Sorry Ol' Dave
Ed Macs do use factory installed blocks of foam to create bouyancy in the event of a catastrophe. BUT... they are either swing keels or water ballasted boats ... a full lead keel is MUCH heavier. Let's just consider the keel, ignore for the moment, the weight of the hull and the difference in density of salt water and fresh water. One cubic foot of water weighs 62+ pounds. To raise a 700 lb weight (my keel) it would take 12 cubic feet of air. To raise a 7,000 keel it would take 113 cubic feet. I'm willing to bet that you're not willing to give up that much cabin space. Like my Daddy said. "Liars can figure, but figures don't lie" So Sorry Ol' Dave
What type of boat???
If you are talking about a smaller boat with a 650# swing keel it can work. non expanding foam is available but you will have to search. There is a lot of space between the liner and the hull that can be filled and it will make the boat quiter. But as others have noted it will be messy work. Tom
If you are talking about a smaller boat with a 650# swing keel it can work. non expanding foam is available but you will have to search. There is a lot of space between the liner and the hull that can be filled and it will make the boat quiter. But as others have noted it will be messy work. Tom
Work on rule #1 instead.
Rule #1 - Keep the water out of the boat. Short of filling half of your interior with foam there's not much you can do to make a lead keeled boat float when full of water. Instead, focus on rule #1. Nothing will help if you have a catastrophic hull failure, but, many boats sink with relatively small holes. Many sink without any hull failure at all, just from some other reason for too much water coming aboard. Look at the GPH capacity of your bilge pump. Considering the rate of flooding through a failed hull fitting, do you have the pumping capacity to handle it? You should have more than enough pumping capacity to handle a complete failure of your largest hull penetration. Adding a couple extra 500 GPH pumps is cheap insurance. And a heck of a lot easier than trying to fill a keelboat with foam.
Rule #1 - Keep the water out of the boat. Short of filling half of your interior with foam there's not much you can do to make a lead keeled boat float when full of water. Instead, focus on rule #1. Nothing will help if you have a catastrophic hull failure, but, many boats sink with relatively small holes. Many sink without any hull failure at all, just from some other reason for too much water coming aboard. Look at the GPH capacity of your bilge pump. Considering the rate of flooding through a failed hull fitting, do you have the pumping capacity to handle it? You should have more than enough pumping capacity to handle a complete failure of your largest hull penetration. Adding a couple extra 500 GPH pumps is cheap insurance. And a heck of a lot easier than trying to fill a keelboat with foam.
Good advice
Pour foam is a bitch to work with. I used it around my fridge and freezer during our rebuild. I had to use twice the amount of product as the specs said. It was probably that 'temperature' thing. No way would I start filling hull voids with the stuff. Not only are rafts a better choice but the helicopter has been invented.
Pour foam is a bitch to work with. I used it around my fridge and freezer during our rebuild. I had to use twice the amount of product as the specs said. It was probably that 'temperature' thing. No way would I start filling hull voids with the stuff. Not only are rafts a better choice but the helicopter has been invented.
But, it could work
Foam supports around 60 lbs per cubic foot. I didn't stay at a Holiday Inn Select last night so I will not attempt the math. The foam will fill voids that would otherwise fill with water in a flooding. This means that the bilge pump doesn't have as much area to pump out. But I was thinking that we still haven't answered the original question, so I did some surfing and came up with this link: http://www.glen-l.com/weblettr/webletters-7/wl55-flotation.html It seems to have been written just for this thread. The linked page ends with the math to keep a boat afloat. I doubt that foam would keep a fully flooded keel boat afloat, but it could slow the flooding and add valuable time. If planning a pour, consider the boat's centre of gravity when flooded. If all of the flotation is in the bilge then the flooded boat may roll over. Biff, I hope it helps.
Foam supports around 60 lbs per cubic foot. I didn't stay at a Holiday Inn Select last night so I will not attempt the math. The foam will fill voids that would otherwise fill with water in a flooding. This means that the bilge pump doesn't have as much area to pump out. But I was thinking that we still haven't answered the original question, so I did some surfing and came up with this link: http://www.glen-l.com/weblettr/webletters-7/wl55-flotation.html It seems to have been written just for this thread. The linked page ends with the math to keep a boat afloat. I doubt that foam would keep a fully flooded keel boat afloat, but it could slow the flooding and add valuable time. If planning a pour, consider the boat's centre of gravity when flooded. If all of the flotation is in the bilge then the flooded boat may roll over. Biff, I hope it helps.
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