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Old 23-06-2016, 19:51   #1
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Boats That Stay Afloat

I didn't want to add this to the discussion about the family on the Seafarer in Florida. That's a tragedy I wish could have been avoided. But, it got me thinking...

The question is: why haven't more manufacturers emulated Etap and Sadler with "unsinkable" boats?
If I were in the market for a monohull, that feature would loom large in consideration of safety offshore.
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Old 23-06-2016, 20:23   #2
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Re: Boats That Stay Afloat

The most likely answer is that folks are not willing to pay the price and/or loose the storage space that is occupied by the flotation. In reality, not many yachts sink, and not so many people worry about t hat happening to them.

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Old 23-06-2016, 23:20   #3
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Re: Boats That Stay Afloat

Yep.. flotation foam takes space.

Appx one cubic ft of foam needed for every 60 lb of boat (including the foam and all contents)

You can carefully place the foam to act as insulation and to put it in unusable space as much as possible... and that might account for 1/4 to 1/2 of the foam needed. The rest would have to be located with the idea of trying to float the boat upright and in a stable manner.

You can add the foam yourself.

Pink insulation foam for houses can be used for controlled application of 1 inch thickness. Its good for use as flotation and cheaper than the pour-in 2-part stuff. Commonly used in restoration of powerboats 10 ft to 25 ft.

Pour in or spray application flotation foam is EXPENSIVE!
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Old 24-06-2016, 06:51   #4
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Re: Boats That Stay Afloat

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Originally Posted by Jim Cate View Post
The most likely answer is that folks are not willing to pay the price and/or loose the storage space that is occupied by the flotation.
This. Lots of space lost, lots of expense, to protect against an extraordinarily remote possibility.

On the other hand, I once read someone postulating that the best thing to do with a liferaft is to keep it below. In the event of a catastrophic holing, inflate it inside the cabin. For a lot of boats, that would be enough to prevent it from sinking. Not sure I buy the whole notion, but something to think about.
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Old 24-06-2016, 09:20   #5
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Re: Boats That Stay Afloat

Don't forget that this particular example involved a much older boat in questionable condition, so even if every manufacturer followed your suggestion starting today, situations like this would still be happening.

I am still flabbergasted at the carelessness of this father placing his children in such a situation. To gamble with your own safety is a personal decision, but the lives of your children involves a greater responsibility that should have made him rethink this decision. I am saddened by the entire situation, but I grieve more for the children who had no choice.
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Old 24-06-2016, 09:23   #6
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Re: Boats That Stay Afloat

Water tight bulk head with dog doors. Would be a solution. Amel mango, shark I and maramu have two at the bow. Super marasmu have five water tight compartment.
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Old 24-06-2016, 09:29   #7
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Re: Boats That Stay Afloat

Unfortunately most boat accidents happen to inexperienced folks. The Seafarer was towing kayaks and it appears that 3 of the 4 crew were not wearing life jackets.

I would think towing one or more kayaks in rough water would be asking for trouble.
Sailing or motoring with a kayak full of water reduces steerage anyway. In rough seas reduced steerage is tantamount to suicide.

A plan, experience, and reliable equipment compensate for an unsinkable molly brown
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Old 24-06-2016, 09:48   #8
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Re: Boats That Stay Afloat

Quote:
Originally Posted by denverd0n View Post
This. Lots of space lost, lots of expense, to protect against an extraordinarily remote possibility.

On the other hand, I once read someone postulating that the best thing to do with a liferaft is to keep it below. In the event of a catastrophic holing, inflate it inside the cabin. For a lot of boats, that would be enough to prevent it from sinking. Not sure I buy the whole notion, but something to think about.
You could easily have a cargo net made from 2" wide cargo strap with clasps that clip all around the inner circumference at seat level and that would hold down air bags made from rubber roofing or vinyl. You might have to walk around on your knees until you get to the nearest port , but your boat would still be usable till you find somewhere to slap on a big patch on it at low tide. At the worst, You'll be riding a few inches lower in the water and that's better than sitting on the bottom of the ocean.
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Old 24-06-2016, 09:51   #9
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Re: Boats That Stay Afloat

Quote:
Originally Posted by snort View Post
I didn't want to add this to the discussion about the family on the Seafarer in Florida. That's a tragedy I wish could have been avoided. But, it got me thinking...

The question is: why haven't more manufacturers emulated Etap and Sadler with "unsinkable" boats?
If I were in the market for a monohull, that feature would loom large in consideration of safety offshore.

Because builders make boats that people want and will buy.
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Old 24-06-2016, 10:07   #10
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Re: Boats That Stay Afloat

I added about 12 ft. of US Coast Guard approved Folman place foam below the sole on my catamaran. I did this because of something I hit about the rudder post caused me to take on water sufficient to have a Mayday.

The foam added after the accident was calculated was sufficient to keep the water level inside the boat under 12 inches per hull to have some minimal sailing control even if hulls were punctured.

The cost was under $500. No storage space was lost. And temperature control was improved.

Part of the reason I sail offshore in the cat is the same flotation cannot be added to a monohull to compensate for the leg keel. I know cats can flip - but with conservative sailing, flipping is less likely than sinking., I think.

I do not believe the commercial airbag systems necessary for mono hall or cost-effective and reliable. US Coast Guard approved foam in place for foam just cannot fail. It adds a little weight to the boat, takes up a little space, makes the boat run quieter, and gives me peace of mind.

It is true that if you can sink underway. It is also true of the few boats ever get underway. When I sailed the lot I felt my risk justify the cost and time. I also appreciated the extra rigidity, small reduction in flexing, and extra strength added to the below waterline parts of my hulls.
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Old 24-06-2016, 10:38   #11
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Re: Boats That Stay Afloat

Sailing a small boat offshore is never going to be 100% safe.

Accidents such as collisions with debris do not have much to do with crew competence and unfortunately life rafts are not a very reliable back up. So an "unsinkable" boat has some appeal for offshore sailing despite the risk of sinking being only small.

I am not a great fan of cored fibreglass structures, especially below the waterline, which leaves watertight bulkheads as the best option. These are only moderately expensive to incorporate at the build stage, but few yachts these days are designed primarily for offshore use.

A collision bulkhead behind the chain locker is common, but the only production boats that I know of that divide the boat into significant watertight areas are Amel, although I believe watertight doors are a popular option on some of the larger Oysters.

Finally metal boats are worth some consideration. The material is fundamentally more puncture resistant. Many models have integral tanks which gives them a double skin over much of the hull.

This is a good article.

The Unsinkable - Professional BoatBuilder Magazine
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Old 24-06-2016, 10:55   #12
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Re: Boats That Stay Afloat

That is a good article!

I've certainly heard this story before:
Quote:
Finally, it is true that relatively few yachts sink due to being holed in collisions (especially with icebergs), but the number that are flooded due to failures of through-hulls or shaft tubes is much larger. During one single month in 1985, I salvaged two sailboats in a single marina that sunk through their toilet fittings (I guess this can be called going down by the head).
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Old 24-06-2016, 11:24   #13
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Re: Boats That Stay Afloat

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That is a good article!

'the number that are flooded due to failures of through-hulls or shaft tubes is much larger. "

I've certainly heard this story before:
Yes, I think that is accurate. Sinking at the dock does not pose the same risk to life as sinking offshore, but any steps taken to reduce the risk are also a help when away from the dock.

With some relatively simple measures, such as seacocks in waterproof compartments (or compartments that are above the waterline), or as in our boat where the seacocks are mounted on standpipes above the waterline, together with measures like cofferdams around the rudder tube, the risks are greatly minimised. Once again these measures are rare, despite the relatively low cost of implementing them.
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Old 24-06-2016, 11:29   #14
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Re: Boats That Stay Afloat

Live-a-board.... where you spend a small fortune to live like a homeless person.
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Old 24-06-2016, 11:33   #15
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Re: Boats That Stay Afloat

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Originally Posted by denverd0n View Post
...On the other hand, I once read someone postulating that the best thing to do with a liferaft is to keep it below. In the event of a catastrophic holing, inflate it inside the cabin. For a lot of boats, that would be enough to prevent it from sinking. Not sure I buy the whole notion, but something to think about.
Just a note of caution:

I was driving a catamaran (back in the 90s) that sank as we were going out.
Maiden voyage of someone's hasty fabrication of a small workboat.

The pontoons were filled with flotation ballons to keep them from filling with water,
but to my dismay they were imploding as the ends got deeper into the water.
(It was part of my job at the time, someone else's boat building,
and everything ended up okay - we were in shallow water, everyone had pfds
and all had BOSIET training etc.)

The point being, a life raft may inflate inside the cabin and it may be enough
to keep the boat afloat unless it has thin skin/gets punctured
or gets too deep to maintain displacement (gets crushed by depth, as I discovered).

Not that it is necessarily a flawed idea, but it suggests careful thought.

cheers to all.
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