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-   -   crash bulkheads on production boats? (https://www.cruisersforum.com/forums/f47/crash-bulkheads-on-production-boats-227151.html)

unbusted67 29-11-2019 18:41

crash bulkheads on production boats?
 
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.

billknny 29-11-2019 18:49

Re: crash bulkheads on production boats?
 
My Amel 53 has SIX water tight compartments.

The chain locker The forward cabin. The main cabin. The engine room. The aft cabin. The aft locker. Each can be fully isolated in the event of a hull breech keeping the boat afloat.

Like you said, it’s a no brainer. With a LITTLE design work it doesn’t even add much cost.to the build.

But nobody else does it. The dollar rules.

atoll 29-11-2019 19:01

Re: crash bulkheads on production boats?
 
all the prouts had them in the bows and sterns compartments
pretty common on most production catamarans

billknny 29-11-2019 19:09

Re: crash bulkheads on production boats?
 
Quote:

Originally Posted by atoll (Post 3026140)
all the prouts had them in the bows and sterns compartments
pretty common on most production catamarans

True enough. But Amels are still the only production boat I know of that divides the accommodation spaces into water tight compartments.

S/V Illusion 29-11-2019 19:10

Re: crash bulkheads on production boats?
 
Given many people routinely want easy access to these spaces (forward cabin, main cabin, engine, etc...), they are routinely left open. If you’ve ever tried closing a door against the flow of anything large enough to sink a boat, it seems like a “feel good” but futile option.

It isn’t as much a matter of cost as it is practicality.

funjohnson 29-11-2019 19:23

Re: crash bulkheads on production boats?
 
There are quite a few productions boats with watertight bulkheads forward- even Catalina and Hunter have these advertised now- but they are typically so tight to the bow to maximise interior space that the value they add is small.

One thing we did in the last boat was to make the area under the v-berth bed watertight. It took a little glass work to seal off the bilge, tab in the bed base all around to the hull, and then bolt the lids in place with rudder gaskets, but this gave us an additional 6' of protection from the bow back and to a foot over the waterline. The area was already dominated by a polyurethane water tank, so i didn't lose any storage. I don't think I've ever seen a production boat make the v-berth bed into a double bottom.

Matt

Dockhead 29-11-2019 19:40

Re: crash bulkheads on production boats?
 
Moodys have crash bulkheads forward, between the anchor locker and the main hull volume. On my boat this is a substantial space forward, and the hull is skinned in Kevlar besides that for crash protection.


Dashew's boats including the Sundeer have watertight bulkheads forward and aft. Very interestingly -- these boats don't have hull penetrations in the main hull volume -- very nice!

funjohnson 29-11-2019 19:51

Re: crash bulkheads on production boats?
 
Quote:

Originally Posted by Dockhead (Post 3026162)
Moodys have crash bulkheads forward, between the anchor locker and the main hull volume. On my boat this is a substantial space forward, and the hull is skinned in Kevlar besides that for crash protection.


Dashew's boats including the Sundeer have watertight bulkheads forward and aft. Very interestingly -- these boats don't have hull penetrations in the main hull volume -- very nice!


Every Hunter over 33' has Kevlar forward too :biggrin: 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

robwilk37 29-11-2019 21:00

Re: crash bulkheads on production boats?
 
my project has a collision bulkhead between the forepeak and the chain locker, isolated rudder post, and is effectively double-hulled with locking lids on all lockers from 8"above the waterline on down. not hard to incorporate when you gut the boat and start from a bare hull...

thinwater 29-11-2019 21:11

Re: crash bulkheads on production boats?
 
My PDQ had 2 forward and 2 fat in each hull. They didn't restrict access.



a. They had forward and aft sections had 6" ports, which is all they needed.



b. The next set were bulkheaded either to the deck or nearly so, with full access through big hatches.


Finally, they were positioned such that ALL of the through hulls were bulkheaded. In fact, on my delivery trip I had a through hull failure. No big deal. Two days latter, at the dock, I pumped out and fixed the problem. Really, they paid for themselves that day just in the water damamge that would have been caused by a foot or so of flooding.


Seems obvious to me.

Tillsbury 29-11-2019 21:11

Re: crash bulkheads on production boats?
 
I’m sure a fair number of larger boats have them to some extent. Behind my anchor locker is a sizeable sail locker accessed only from a deck hatch, and the rear bulkhead there is a good 8-9 feet from the bow with no opening into the main boat interior. It’s well tabbed to the hull as it is the support for the optional cutter rig. Only any use for a direct frontal hit of course, but it’s a start. The rear lazarette is huge and only accessible from two relatively small hatches in the rear cabins. It has occurred to me that it would take a relatively small amount of glasswork and reinforcing of these hatches to isolate the entire rear 6-8 feet of the boat too, which of course includes the rudder post - a potentially catastrophic failure possibility. I don’t know if I could make it 100% waterproof but the job is to make it good enough that if it were full to the waterline there would be only enough coming into the boat that bilge pumps could comfortably handle.

s/v Jedi 29-11-2019 21:32

Re: crash bulkheads on production boats?
 
Yes we have watertight bulkheads forward and aft. The living space in between these two is just 38’ in a 64’ waterline boat. This means that both fwd and aft compartments can flood without sinking.

There is a standpipe for discharge in the center section.

robwilk37 29-11-2019 21:36

Re: crash bulkheads on production boats?
 
thread hijack - your standpipe is for galley sink? no seacock? asking because im surprised more boats dont incorporate them...

billknny 29-11-2019 21:46

Re: crash bulkheads on production boats?
 
Quote:

Originally Posted by S/V Illusion (Post 3026149)
Given many people routinely want easy access to these spaces (forward cabin, main cabin, engine, etc...), they are routinely left open. If you’ve ever tried closing a door against the flow of anything large enough to sink a boat, it seems like a “feel good” but futile option.

It isn’t as much a matter of cost as it is practicality.

Ahhhh... that's an interesting way of talking yourself out oa a good idea.

On an Amel, the watertight doors open AWAY from the main cabin, so the most likely flow of water is pushing to door CLOSED, and the engine room is sealed always from the main cabin, the only access is down through the cockpit sole. The chainlocker and aft locker have no routine access from the main cabin at all.

It IS a practical solution. I have seen an Amel floating after a hurricane pushed a piling though the hull until it hit the keel. Waterproof compartments WORK.

s/v Jedi 29-11-2019 21:50

Re: crash bulkheads on production boats?
 
Quote:

Originally Posted by robwilk37 (Post 3026208)
thread hijack - your standpipe is for galley sink? no seacock? asking because im surprised more boats dont incorporate them...

It is for the pilothouse drains (like cockpit drains), the grey water holding tank has a pump discharging in it, as well as the center compartment bilge pump.

All the sinks and both shower have a gravity drain into the holding tank, just like a house :thumb:


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