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Old 02-12-2019, 11:46   #61
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Re: crash bulkheads on production boats?

That's an interesting fact about the Amels. By definition, in the world of ship/boat design, "watertight" means exactly what it says. The door or hatch must be able to be sealed so that virtually no water is able to pass from either side, and the door-bulkhead system must be able to withstand a full head of water from either side. Someone mentioned that lots of submarines have been sunk even though they have numerous watertight doors. Almost all submarines that have been sunk were dived at the time they were attacked. In any dived condition the boat has neutral buoyancy (zero reserve buoyancy), along with greatly increased water pressure due to depth. In this condition, ANY ingress of water results in negative buoyancy, and any breach in the hull results in catastrophic implosion.
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Old 02-12-2019, 12:36   #62
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Re: crash bulkheads on production boats?

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As I learned it in the Coast Guard, a "watertight compartment" is a space that cam be completely sealed off so that no water can enter from any direction, even over the top. I believe most people here are confusing "watertight compartments" with watertight bulkheads, which separate bilge areas, but can be overtopped by influx of water, possibly flooding the next compartment. This is what happened to the Titanic, which did NOT have watertight compartments, only water tight bulkheads. In 65 years of sailing, I have never seen a yacht with watertight compartments except for a couple of arctic-classed all-metal boats.
Our five areas are all watertight compartments using the above definition.
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Old 06-12-2019, 08:50   #63
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Re: crash bulkheads on production boats?

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Originally Posted by funjohnson View Post
Every Hunter over 33' has Kevlar forward too They don't define how far back the Kevlar goes, but even if it's an inch, they can add it to the advertisement.

If I remember correctly, the Moody has it back to the keel stub.. is that right? Is it on the inner or outer side of the coring?

Matt
Steve Pettingill told me my Hunter 356 had a sealed Kevlar chamber from the bow stem to the keel stub as well as the sealed chain locker above it.
The rudder post was enclosed up to the cockpit floor with a stainless Cobra steering rod to the wheel pedestal.
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Old 06-12-2019, 14:41   #64
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Re: crash bulkheads on production boats?

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Originally Posted by Hardhead View Post
Here's the helpful gist of it from the author:


"It also makes no economic sense for the shipping industry to equip the many millions of containers in service with special safety gear to protect a very small number of sailors against a tiny threat of harm."


There you have it - industry has spoken, and money makes laws.

I wonder if one could mount a RFID transmitter on the front of a boat with an alarm if it picked up a signal. It would depend on a bunch of unknowns. What are the range of shipping container RFID tags (a few inches or 300m), where are the transmitters located, are they resistance to seawater, what is the penetration capabilities of RF to trigger a tag just under the surface of the water, etc).



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Old 06-12-2019, 16:22   #65
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Re: crash bulkheads on production boats?

What you need is a fleet of small drones that fly around and ahead your boat in a swarm to scout for hazards, pirates etc.
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Old 06-12-2019, 16:41   #66
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Re: crash bulkheads on production boats?

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Your choice of boat doesn’t change the fact that the brands you mention are production boats. Do you think a Sundeer costs more than an Oyster, Contest, Hallberg Rassy, Chris White, Amel etc.? Which ones have watertight bulkheads and which don’t? Many report they do, Alden 50 with as many as Bestevaer.
Jedi,

Sorry for the late reply.

I don’t have the data on hand to argue, nor the desire to spend time looking it up. I’ll just say this that that gaggle of boats IMHO would be more considers either semi-custom or LOW production/high quality units. They are surely high dollar value boats.

When someone says “production boat” my mind goes to boats that are produced off a production line for no particular user and with a high premium based on low cost. Hunter, Bavaria, Jeanneau, Catalina, etc.

To my mind there is a world of difference between this list and the ones you mention.

The question in my mind is how much additional (as a % of initial sale price) would it cost to add these bulkheads to your common Hunter, Bavaria, Jeanneau, Catalina?

You want to call you list “production boats that’s fine as long as you are clear what brands you are including.
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Old 06-12-2019, 16:48   #67
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Re: crash bulkheads on production boats?

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Oops no attachment Attachment 204193
Distressing. This is a nearly 200’ long steel SHIP.

One would think that it would be if substantial scantlings.

I’m surprised that it could be taken down by a shipping container, if that’s what it was. If not then what was it? I’ve heard of floating dock sections and I also know that sometimes ships can sink very slowly, sometimes hanging just at or below the water. And was it big enough for a US Navy destroyer to be sustain similar/substantial damage? Lots of questionnaires.


Quote:
The skipper consequently “confirmed that the vessel had sunk off Indonesia after hitting an object in the water,” the coastguard said in a statement.
https://www.noonsite.com/news/indone...tified-object/
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Old 06-12-2019, 17:49   #68
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Re: crash bulkheads on production boats?

Our Lagoon 440 has crash bulkeads in the bows
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Old 12-12-2019, 14:18   #69
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Re: crash bulkheads on production boats?

Catalina 425 has a crash bulkhead filled with foam to dampen an impact like hitting a partially submerged container. All Catalina rudders are built asymmetry so they are less likely to split open along the leading edge.
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Old 15-12-2019, 14:09   #70
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Re: crash bulkheads on production boats?

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Are there any production boats that have separate bulkheads for rudder spaces? What about a collision bulkhead in the bow? Seems like a no brained from a safety standpoint.

I sailed on an Oyster that had a watertight door to the forecabin. It was a nice wooden finished one but with massive handles, not the kind of industrial style one you get on engine rooms for example. This was an optional feature but Oysters are made for long distance offshore cruising so it makes sense.
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Old 19-12-2019, 15:55   #71
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Re: crash bulkheads on production boats?

My Amel Super Maramu has 6 of these...
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Old 19-12-2019, 16:39   #72
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Re: crash bulkheads on production boats?

My Amel 50 has 6 watertight compartments also!
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Old 20-12-2019, 07:37   #73
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Re: crash bulkheads on production boats?

I mostly have sailed on the Great Lakes, but I also sailed on the Atlantic East Coast, the Caribbean, and the Gulf of Mexico. I have never knowingly hit a container but I know of at least a dozen times I have knowingly hit logs. I sailed a Catalina 30 for 9 seasons, a Beneteau Oceanis 50 for 1 season, a Beneteau Oceanis 41 for 2 years, my current Beneteau Oceanis 321 for 4 seasons, and a few other production boats. Luckily I have had zero damage other than some scuffed bottom paint.

Reading this thread has movitated me to inspect the bulkhead between my chain locker and the forward cabin and see if it is watertight. If it isn't, I will do what I can to make it watertight. I do admire the collsion engineering of the Amel and the other boats mentioned in this thread, but I still have confidence in the quality of engineering in Beneteaus.
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