Floatation of wet foam

[JimInPB]

Interesting. What Beneteaus? I'n not personally aware of any with positive flotation. My real question is what is the rational for wanting it? Sinkings are so rare, and even then the boat awash to its decks is not any better (worse actually in most conditions) than a liferaft.

I was not stating that Beneteaus have positive flotation. I was stating that I would find positive flotation to be a valuable feature on a keel boat like a Beneteau, in answer to your original question.

Beneteau sinkings do happen. Cheeki Rafiki would be the most recent well-publicized example that comes to mind. Beneteaus do have a bit of a checkered reputation for keel bolt issues. Perhaps it is well deserved. Perhaps it is not.

The last time that I went any real distance in a Beneteau was a trip from Miami to OBX. the intended course took us over 100 miles from shore, to cut the corner by Georgia & save time. I happened to be the person in charge of the life raft during that particular excursion. I also kept an eye on the kayak that was strapped in near the bow, because I wanted to have plan B in case something went wrong with the life raft. I always want plan B to be available when I am 100 miles out. If the kayak was not there, a floating hull might present a plan B.

The 79 Fastnet race was my first real wake up call to the dangers of being caught in unforecast energetic storms, even in a good boat. Google "Grimalkin". You will see what I am talking about. I have been caught out there like that more than once. The concept has been firmly reinforced in my perspective.

Jack, at this point, we seem to be taking this conversation pretty far off from the original topic. Would you prefer to start a different thread?

 

[JimInPB]

...
I'd like to fill in the gaps between it with marine foam rather than fill the whole cavity for cost reasons, but I want to know if that will prevent if from getting waterlogged or whether the water will enter the old (but encapsulated) foam anyhow.
The other advantage to this is that if I can fill all the gaps between the foam blocks I'll have more flotation and so can open up some of that space for water storage.

How much foam are you looking to replace? Judy's source sells more than 2,000 pounds of buoyancy for less than $300.

I am not understanding how more foam will let you carry more water. I may be misunderstanding what you are trying to say.

 

[Jackdaw]

I was not stating that Beneteaus have positive flotation. I was stating that I would find positive flotation to be a valuable feature on a keel boat like a Beneteau, in answer to your original question.

Beneteau sinkings do happen. Cheeki Rafiki would be the most recent well-publicized example that comes to mind. Beneteaus do have a bit of a checkered reputation for keel bolt issues. Perhaps it is well deserved. Perhaps it is not.

The last time that I went any real distance in a Beneteau was a trip from Miami to OBX. the intended course took us over 100 miles from shore, to cut the corner by Georgia & save time. I happened to be the person in charge of the life raft during that particular excursion. I also kept an eye on the kayak that was strapped in near the bow, because I wanted to have plan B in case something went wrong with the life raft. I always want plan B to be available when I am 100 miles out. If the kayak was not there, a floating hull might present a plan B.

The 79 Fastnet race was my first real wake up call to the dangers of being caught in unforecast energetic storms, even in a good boat. Google "Grimalkin". You will see what I am talking about. I have been caught out there like that more than once. The concept has been firmly reinforced in my perspective.

Jack, at this point, we seem to be taking this conversation pretty far off from the original topic. Would you prefer to start a different thread?

I'm very familiar with the 79 Fastnet race, and lessons learned. The Grinalkin did not sink, or become awashed, so not sure what you point is here. Of the two crewmenbers that remained on board, one died of exposure, and the other was close. And this was on a boat that was close to floating on her lines.

I totally agree that Plan Bs are a great idea. Or maybe its really plan C. Plan A should always be to keep the 'boat' a 'boat'. Once it stops being a boat, Plan B should always be a liferaft. In many countries (like France) you cannot sail offshore (20nm) without one. Plan C could be staying on an awash deck, but in bad conditions like Fastnet79 that would have been a death sentence. Or in a fire.

FYI the Cheeki Rafeeki incident has been officially blamed on incorrect repair of previous keel damage. As far as I know there has never been a Beneteau keel failure that can be attributed to design or construction, can you point to one that would back your comment??

LOL I just saw your comment about a separate thread! ;^)

 

[Gunni]

Do the math, your boat weighs what 1 ton? You would need something like 36 cubic feet of closed cell foam to float an empty boat cabin-top level with the water. Add yourself, your funny little hunny, you outboard, your barley pop and pretty soon you have a boat full of foam. You are headed down a dead end here. Good seamanship, weather skills, and obeying small craft warnings is the course you need to take.

 

[Jackdaw]

Do the math, your boat weighs what 1 ton? You would need something like 36 cubic feet of closed cell foam to float an empty boat cabin-top level with the water. Add yourself, your funny little hunny, you outboard, your barley pop and pretty soon you have a boat full of foam. You are headed down a dead end here. Good seamanship, weather skills, and obeying small craft warnings is the course you need to take.

With the exception of the keel/ballast, the remainder of most boats is surprising close to buoyancy neutral. So that's about how much water you end up needed to displace to keep the deck awash.

But I totally agree with your bigger point. Keeping the 'boat a boat' is very easy, and non raceboat-related sinkings (on lakes in particular) are very very rare.

 

[JimInPB]

I'm very familiar with the 79 Fastnet race, and lessons learned. The Grinalkin did not sink, or become awashed, so not sure what you point is here.

The point is that when you find yourself far offshore, when things go wrong, anything that floats, become a valuable asset. This is in direct response to your original question.

FYI the Cheeki Rafeeki incident has been officially blamed on incorrect repair of previous keel damage. As far as I know

Does the reason for the failure really matter? The boat was offshore & became unable to sail. At that point, anything that floats is better to have around than something that does not float.

there has never been a Beneteau keel failure that can be attributed to design or construction, can you point to one that would back your comment??

I commented that they have a checkered reputation in regards to keel bolts. I tempered that comment with an option that perhaps it is deserved & perhaps it is not. I did not state that design or construction have been documented to cause keel failures. I do not wish to devote the time to researching the validity of a statement that I did not make. I can find your plenty of people who don't trust those keel boats. I can find plenty of people who have replaced them.

LOL I just saw your comment about a separate thread! ;^)

Well then?

 

[Justin_NSA]

The 26c had a surprisingly small amount of foam in it, and the video showed it down to the rub rails. I think Jackdaw is referring to the added incentive of a few thousand pounds of lead wanting to drag it down. The math homework ( which I neglected to do) probably suggests that there isn’t enough foam to prevent the keel from winning the struggle.

I was going to say, well a 26S has a couple thousand pounds of ballast too, but it is water not lead or iron so not the same as a keelboat. But the M25 has an iron keel doesn't it? Does flotation really help on them?
I've read on the Mac forum that some people use those foam noodles instead of the block styrofoam. We are in the process of finishing up replacing all of the styrofoam dock flotation with approved encapsulated flotation. The old stuff is so heavy with water that it takes a forklift to move it on the pavement. It floats, but not like new.

 

[Gunni]

I get it that folks with a daysailer have a very real fear of their boat sinking out from under them. But surviving is A LOT more than having something to hang onto. Even off south Florida your hypothermic survival time is measured in a few short hours. So rather than a magical cruiser that floats, builders meet strict Class C construction that keep boaters in the boating mode, not the floating mode.

If you are in a daysailer you don’t have that kind of boat and are expected to heed warnings and your skill level and stay on the ramp. That is your survival mode. These ongoing fears of keels falling off and boats sinking are the stuff of inexperienced sailors who don’t understand how a blue water boat is built and how you sail it. Unless you are sailing some junk you found behind a barn and gave it a lick and a promise you should never find yourself in such a situation, so you have to be knowledgeable and able to inspect your gear.

In an off-shore rated boat you layer on systems that allow you to transition to abandon ship survival mode in an orderly fashion and you do so with a lot more than having something to hang onto. You will need a raft, protection, drinking water, food and the ability to call for help. Hanging onto a sunken hull is a very poor substitute. In fact the Cheeki Rafiki cited here was found afloat...with no survivors.

 

[DrJudyB]

Per JimLmPb's comment, I'm trying to improve the flotation in my Mac25. I have a bunch of open cell foam that's pretty dry, but as Judy says it water logs quickly when submerged so I don't want to trust it with my family.
I'd like to fill in the gaps between it with marine foam rather than fill the whole cavity for cost reasons, but I want to know if that will prevent if from getting waterlogged or whether the water will enter the old (but encapsulated) foam anyhow.
The other advantage to this is that if I can fill all the gaps between the foam blocks I'll have more flotation and so can open up some of that space for water storage

@fritz3000g :
Are you sure the flotation foam in your Mac25 is open cell? Open cell foam is typically used only for interior settee and vberth cushions because it's soft and squishy.

You can't squish open cell foam. You can bend and flex it sometimes, but it does not compress very much.

IMO, trying to seal open cell foam by surrounding it with closed cell foam is not a good idea Remove it and replace it with something else if you want reliable flotation. Even a net full of empty water bottles that is secured to the boat would be less prone to failure. Or buy the marine grade stuff. Or use pink foam or styrofoam, but inspect it regularly because it's not reliable over the long term.

 

[Jackdaw]

The point is that when you find yourself far offshore, when things go wrong, anything that floats, become a valuable asset. This is in direct response to your original question.


Does the reason for the failure really matter? The boat was offshore & became unable to sail. At that point, anything that floats is better to have around than something that does not float.


I commented that they have a checkered reputation in regards to keel bolts. I tempered that comment with an option that perhaps it is deserved & perhaps it is not. I did not state that design or construction have been documented to cause keel failures. I do not wish to devote the time to researching the validity of a statement that I did not make. I can find your plenty of people who don't trust those keel boats. I can find plenty of people who have replaced them.


Well then?

None of this really addresses my points, so I'm not going to comment except for this.

You say:

Beneteau sinkings do happen. Cheeki Rafiki would be the most recent well-publicized example that comes to mind. Beneteaus do have a bit of a checkered reputation for keel bolt issues.

but when pressed to explain regarding failures you say

I do not wish to devote the time to researching the validity of a statement that I did not make

But you DID make it. I'd be more careful.

 

[JimInPB]

Jack, you misquote me again.

Please start your own thread.

 

[Jackdaw]

Jack, you misquote me again.

LOL - Those are your EXACT words.

 

[DrJudyB]

@fritz3000g :
I would assume from your posts that you is a relatively inexperienced sailor who wants to sail safely with his family in his new-to-him boat. Forgive me if I underestimate your level of sailing experience. please.

I hope you will have fun sailing your Mac. The Mac 25 is not a blue water boat, but you can still have a heck of a fun time sailing it, like tens of thousands of day sailor owners have for decades.

IMO, you're being prudent and careful to ask about the foam floatation in your Mac 25. Replacing saturated floatation foam is a good idea. The Mac 25 is a good daysailor, but it IS lightly ballasted and there is a small chance you might capsize or swamp it if you do "everything wrong."

Having foam flotation is a good idea... and taking lessons is an even better one. Lessons will teach you how to avoid doing "everything wrong".

If you aren't confident that you are skilled enough to take your boat out with your family. my personal recommendation is that you and your family members take sailing lessons from a certified ASA or USSailing instructor on your boat or a similar sized boat. Lessons cost more than foam, but theyre worth every penny if they make sailing fun for you and your family. It's fun when you can sail with confidence.

 

[Jackdaw]

I hope that that OP (and others) don't think that I'm biased against boats or builders that use or have positive flotation. Indeed, my favorite boat in the world, the ocean-going Pogo 12.50, has it. And I don't understand why. Its a personal question, I was wanted people's input on in what conditions it might realistically help them.

 

[DrJudyB]

I was wanted people's input on in what conditions it might realistically help them.

Here's my two cents:
Unsinkable is a legitimate feature targetted at new sailors (and maybe experienced sailors.)
I think we can all agree that it's very important to have positive floation in a boat with low stability.
For boats with high stability, flotation reduces the available stowage and/or drives up cost.

A few high stability boats, like the Etap, are unsinkable, even when holed by a container or deadhead.

Different strokes for different folks.

 

[Scott T-Bird]

It seems to me that the whole exercise of calculating the difference in flotation between waterlogged open cell foam and closed cell foam is just a wasted effort. What difference will it make? Other than the effort to create additional storage space, we don't seem to really understand what is the purpose? Why are you interested in water-logged buoyancy capacity anyway? If you want to maximize storage space, you need flotation that won't absorb water, period. Why in the world would you be concerned about how much water is absorbed in 30 days if you surround open cell with closed cell flotation? I guess I'm just not getting it. I guess my suggestion would be to fill it with as much closed cell you can fit in the space you want to fill and be done with it. What is the point of doing the calculations?
When it comes to the difference between a keelboat and a boat with positive flotation, I'm in favor of a keelboat and don't think anything about positive flotation. It reminds me of our experience when I was growing up. We had a summer cottage on a lake and my mom insisted that we must have a sailboat. My poor dad, who was much more interested in farming than he was in boating, felt like he had to comply. First he bought a Sea Scouter, which was a tiny little open boat that capsized easily. It was a tremendous nuisance because each time it did, you couldn't bail out the water so it had to be dragged to shore. The trick was to keep it from turning turtle, but one time it did, and the mast slid out of its slot (with the sail) and rested on the bottom of the lake 40' below never to be found.
May dad was forced to buy another. This time it was a Ghost 13, which was so light that until the sails were filled the crew of 1 or 2 had to balance on the centerline or over you would go. My mom refused to sail it. My dad said he should never have been sold a boat where they advertised how easy it was to get righted after a capsize. I never liked the advertising that shows a sailboat floating completely awash in water. It doesn't paint a very good picture.

 

[Jackdaw]

Here's my two cents:
Unsinkable is a legitimate feature targetted at new sailors (and maybe experienced sailors.)
I think we can all agree that it's very important to have positive floation in a boat with low stability.
For boats with high stability, flotation reduces the available stowage and/or drives up cost.

A few high stability boats, like the Etap, are unsinkable, even when holed by a container or deadhead.

Different strokes for different folks.

Hi Judy. I understand the THEORY, I'd like to hear about why someone personally made the choice. You didn't - your boat will sink if holed! ;^)

The Etap case is interesting. Take the best case were an Etap 35i gets holed offshore. She settles in the water down to her gunnels and stops sinking. If you don't have a life-raft, thats a good thing she stopped. But you should have one. In good warm weather you could stay on the deck, but in sea state, cold air/water or rain/squall you are much better off in the raft. And keeping it afloat? If salt water gets to my boat up to the deck, its a write-off for me.

 

[JimInPB]

LOL - Those are your EXACT words.

View attachment 148359

Jack,
you are still miss-characterizing what I said. I stand behind my previous words. Your interpretation is off. Please start your own thread & I will be happy to address each of your comments.

 

[walt]

Here's a general question: Do people find positive buoyancy in a keelboat to be a valuable feature? If so, from what fate? I'm just curious.

I have not messed with the flotation that came with the boat for one main big reason.. Liability.. Some day I will sell the boat and dont want to be concerned about who I sell it to. If the new owners do something really fricken stupid and something bad happens, I dont want any of that liability because I altered a safety feature the manufacture had designed in. I may be a little too paranoid here.. but I get to take whatever risks I want and this is one that is not on the list. Plus.. just no big deal to leave it as is.

 

[Jackdaw]

I have not messed with the flotation that came with the boat for one main big reason.. Liability.. Some day I will sell the boat and dont want to be concerned about who I sell it to. If the new owners do something really fricken stupid and something bad happens, I dont want any of that liability because I altered a safety feature the manufacture had designed in. I may be a little too paranoid here.. but I get to take whatever risks I want and this is one that is not on the list. Plus.. just no big deal to leave it as is.

That's interesting. I remember in the years just before airbags, some cars had motorized seatbelts as a stopgap. They were diabolical, and a friend modified his VW Corrado so the belt functioned manually. I remember thinking 'good luck selling that'.