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Old 15-05-2011, 06:22   #181
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Re: Floating Containers In the Ocean

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Originally Posted by Swede57 View Post
Don't believe in export either then
He had not thought of that.
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Old 15-05-2011, 07:00   #182
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Re: Floating Containers In the Ocean

Forward looking sonar is only good for slow speed and usually used when feeling your way into an anchorage or an unknown inlet. The scan rate and display is much to slow to be used at any speed other than slow. The display is also difficult to interpret and takes a lot of practice to get it right.

Hey Mark, what were you guys praying for in post 159?
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Old 15-05-2011, 07:44   #183
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Re: Floating Containers In the Ocean

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The Titanic was unsinkable! If you get cut in half then you have a choice. the part that floats and the part that sinks (water tanks fuel engine etc) Just don't hit anything or let anything hit you

This was not true. Neither the designers, builders, nor owners of the TITANIC EVER said it was "unsinkable"! It is a MYTH!!! It was a pervasive "story" that was started by a newspaper reporter, when the advantages of the 3/4 height bulkheads were being explained. The ship was built of steel, a decidedly NON buoyant material.

Regarding our Searunner however... If you look at a copy of The Searunner Construction Manuel you will find a photo of a large Searunner dangling from a crane. The entire bottom of ALL THREE hulls are missing and you can look up at the sky! It had been repeatedly rammed by an angry whale, never sank, and while mostly awash, it made it back to the dock to later be rebuilt.

This was the old Searunners... (25,31, 37, & 40) They either had metal non buoyant connectives, (25 or 31), or they had wings that were open from the main hull to the amas for additional storage. Even THEN, they were unsinkable.

The 34 however, (like we have), was designed many years later, as an answer to: "how can we improve Searunners"? Unlike the others, the wings are totally sealed, and broken up into many separate air void compartments. I have 8, "o" ring deck plates, to inspect these voids.

Now, it is not only unsinkable, but floats NOT totally awash, and in mild conditions, could continue "down wind" on it's way. VERY slowly of coarse. Upside down, with the amas' air locks, she bobs like a cork!

Water is weightless in an awash boat, all fuels actually float, as do the cushions, jugs, fenders, and much of the boat's contents. Only the engine, batteries, and tools continue to weigh something in an awash boat.

This is NOT like a FRP boat. Our hull material itself is naturally buoyant, many times over more so than the weight of the 600 or so pounds of non floating contents... And this would be true, even with 500 holes in it!

Our 34, with it's sealed wings, is many times over more buoyant that in the previous case above. It floats @ the cockpit sole if totally awash, OR upside down.

The crew has been known to survive as long as three months in an upside down trimaran. "The story of the Rosey Noel".

So, while fire, or cold water, could easily make this safety feature a moot point... Regarding hitting containers, in normal seas & warm climate, it gives me peace of mind. If any one of the hulls were holed, I would goop up a scrap of plywood, nail it into place, pump out the hull, and resume on my way. This sort of thing has been done MANY times.

I don't think that our unsinkable trimaran, OR the ETAK unsinkable monohull, OR a submarine door bulkhead "flood resistant" monohull, makes us invulnerable to the perils of the sea by any means, and I didn't mean to imply that it did. There are a LOT of ways to die at sea!

My boat's "unsinkable nature", just like a solid foam surfboard, is, however, a fact, NOT just a claim made by an ignorant reporter trying to sell papers with exaggerated headlines.

The subject was containers... The risk of, etc. My suggestion, weather it is with one hull or several, is to have an ace in the hole, (no pun intended). Something like: An unsinkable hull material, buoyancy compartments, automatic air bags, or a "submarine door" bow bulkhead. To one degree or the other, it helps to alieve "that sinking feeling".

M.
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Old 15-05-2011, 11:36   #184
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Re: Floating Containers In the Ocean

Hi I like the idea of air bags. have you seen them used/installed on any boat?
Re unsinkable see.
snopes.com: The Unsinkable Titanic

"However, claiming (as White Star did) that although others may have used the word, White Star itself did not describe the Titanic as "unsinkable" in its advertising is a bit disingenuous.

The February 1993 issue of The Titanic Commutator unearthed a White Star promotional flyer for the Olympic and Titanic that claimed "as far as it is possible to do, these two wonderful vessels are designed to be unsinkable."

Perhaps that statement encapsulates one of the key lessons the world should have gleaned from the Titanic disaster: When dealing with matters of safety and human lives, "possible" and "practical" are two very different things."



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Old 15-05-2011, 21:18   #185
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Re: Floating Containers In the Ocean

Thanks everyboddy, it seems one should plan this for when one do antfowling and your boat is on the hard. Mark out the areas you want to remove the gelcote from which in your opininion are the critical areas. I bielieve the hull and as high up as just above the waterline with more emphasis on the bow area and aft. Strengthening the chain locker chamber from the inside should complete my ease of mind, but to make certain that this project is correctly applied i would search out a reputable builder to complete the project effectively and professionaly. I would make sure that whoever do the work do apply not Kevlar but Kevlar KM2.
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Old 17-05-2011, 11:43   #186
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Re: Floating Containers In the Ocean

Our boat has a separate crews quarters with a bulkhead in between. The water would have to be about 3-4 feet up to spill through a small hole where the windlass wiring and plumbing go through. I imagine this would help, but if we hit the container aft of this cabin, it would be a different story.

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Old 17-05-2011, 21:26   #187
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Re: Floating Containers in the Ocean

Yea Brad that's certainly true but as some earlier said "my boat has a bulet proof jacket" and there is all the reasons why one should seriously considder strenghtening your hull to at best help your vessel if your avoidance plans do not succeed. In this instance i am referring to Kevlar KM2 which is freely available.
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Old 17-05-2011, 21:33   #188
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Re: Floating Containers in the Ocean

Niel, the various offshore racing organizations and events have examined this topic for decades now. The answer is to remove the interior from the boat, reinforce the hull on the interior so you don't screw around with the gel coat, and add collision bulkheads and watertight doors, just as ships do. You'll have to remove the interior to install the bulkheads anyway.

Some of the rules require one collision bulkhead forward, others require two with the second further aft.

And the Titanic has taught us not to allow coal fires in the coal bunker to smolder, and not to allow inferior iron or riveting.

Bullet proof is a relative term, for any "armor" there is always a bigger bullet to penetrate it. Like that guy on the west coast who got bounced on by a whale. (Ouch!)
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Old 17-05-2011, 22:23   #189
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Re: Floating Containers in the Ocean

Hi, i totally, totally aggree! There is just no 100% bullet proof way! I feel that if i can add one percent to myself and my crews safety by making some adjustments one way or the other, i'll grab that with both hands.

I plan to when my boat come out for antifowling to determine the exact fully laden waterline, remove the gelcote on both hulls in that marked area. Apply the Kevlar KM2 on that cleaned area to a thickness of between 3 to 5 mil and reapply the gelcote or paint. That weight increase is certainly justified in my opinion. As i said if it increases our safety chances by one percent i will be happy!
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Old 18-05-2011, 04:20   #190
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Re: Floating Containers in the Ocean

By beefing up the bow would be prudent to consider the impact (lol) of higher shock loads passed through the rest of the vessel - especially bulkheads. Think crumple zones on cars.

Although perhaps a bit low tech for some. Looking out of the window used to work quite well...........
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Old 18-05-2011, 07:20   #191
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Re: Floating Containers in the Ocean

Agreed and point well taken. I am of opinion if one sort of beef up the chain locker and airlock with Kevlar KM2 from the inside with light weight shock absorbing material to absorb as much of the shock from the impact as possible. Whatever filters through to the bulkhead should not critically (LOL) upset the apple pie!
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Old 18-05-2011, 10:56   #192
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Re: Floating Containers in the Ocean

"Apply the Kevlar KM2 on that cleaned area to a thickness of between 3 to 5 mil"
One "mil" is one thousandth of an inch, five mils is still about one tenth of on millimeter thick. A flimsy plastic shopping bag.
Perhaps you mean five millimeters of thickness? Because five mils of kevlar isn't going to slow a shipping crate down very much, even if you can get the cloth that finely woven.

Might make for good fireproof bedsheets though.<G>
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Old 18-05-2011, 14:07   #193
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Re: Floating Containers in the Ocean

Hello Sailor,

Ok you made your point, the planned thickness is actually between 3 millimetres to 5 milimeteres. Using a mil as a abreviation was bit reckless, thanks for reminding!
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Old 26-05-2011, 12:47   #194
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Re: Floating Containers in the Ocean

Is there anyone with KevlarKM2 experience who can give some guidlines.
Kevlar KM2 is elastic whilest glasfibre with gelcote is rigid. If one fix Kevlar to the ouside of the hull and you hit a floating object the Kevlar will expand inward causing the galss to crack and leak? If you stick kevlar in the inside the glas will rapture inwards as the object penetrate and the kevlar should strech, question is will kevlar keep the water out while expanded? It somehow seem like a question of youre damned if you do and damed if you don't!
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Old 26-05-2011, 14:07   #195
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Re: Floating Containers in the Ocean

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Originally Posted by niel12 View Post
Is there anyone with KevlarKM2 experience who can give some guidlines.
Kevlar KM2 is elastic whilest glasfibre with gelcote is rigid. If one fix Kevlar to the ouside of the hull and you hit a floating object the Kevlar will expand inward causing the galss to crack and leak? If you stick kevlar in the inside the glas will rapture inwards as the object penetrate and the kevlar should strech, question is will kevlar keep the water out while expanded? It somehow seem like a question of youre damned if you do and damed if you don't!
Well, another approach would be to forego the Kevlar and its inherent laminating problems, and simply build up the appropriate areas with more glass. Cheaper, well known methodology, and while it might well weigh a bit more, could offer as much reinforcement as you might wish.

Use of asymmetrical weaves or even unidirectional glass could add considerable strength to your tender parts!

Cheers,
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