crash bulkheads on production boats?

[Discovery 15797]

Originally Posted by jmh2002

Despite the warm fuzzies that author Charles J. Doane wishes to bestow on us (which mostly seems to be along the lines of 'ah, don't worry about it...') the anecdotal evidence seems to suggest (to me at least) that the odds are changing, quite rapidly...

One can even see it, by the much larger amount of 'stuff' - be that rubbish, junk, debris, etc, that now floats by us much more regularly at sea

Interesting...I did not get that from the article. He clearly states,

"This is a risk you take when you sail offshore, and you cannot reasonably expect anyone to obviate it for you. You can obviate the risk yourself by keeping a good watch..."

Anecdotal evidence is just that...unreliable, hearsay, data-less. Just as with modern news...the hyper-emotional and overly sensationalized speculative viewpoints portrayed sometimes do not reflect reality or data backed by actual statistics. But, they tend to be the stories that stick in our minds the most, and paint a picture we want to see regardless of the facts.

I see flotsam and jetsam all the time. I've hit more partially submerged objects in Puget Sound than in Pacific crossings, or the South China Sea. I am not arguing flotsam and jetsam do not pose a danger, however, statistically sailboats suffer greater damage running up onto a reef than being holed mid-ocean by a lost container.

Statistically...the vast majority of sailing is inland waters and near coastal, and rarely night passages. Thus, manufactures who want to sell boats may conclude that water-tight bulkheads would significantly increase costs while providing very little value add for the majority of sailboat owners. (Obviously I'm speculating here since I'm not a boat manufacturer.)

On a recent passage from SF to Hawaii, USCG Honolulu sent out a hazard to nav warning on VHF of 2 FADs (fish attracting devices) that had broken loose and spotted earlier in the evening. About 2 hours later at about 23:00 local time I picked them up on radar and passed within 4 nm of them. These FADs are so much a danger to navigation they are specifically warned about in the Coast Pilot Vol 7. Also, on that trip I had a piece of 3' x 10' netting get fouled in my prop, and passed a mounted car tire, a plastic 55 gal drum, and a large black plastic buoy of some sort.

[toddster8]

While not a “watertight compartment,” my small production boat does have a plywood crash bulkhead below the V-berth, isolating the forward-most compartment to about six inches above the waterline. (Well, the second-most. The anchor locker in the bow is entirely above the waterline.) I’ve often thought that it could use one aft, to isolate the rudder post. One could be added, but it would be a bit of a nightmare to gain access and re-route cables and ventilation hoses. On paper, it looks as if the settees and bunks along the sides could be made into water-tight cells to the waterline, but in practice, ventilation and utility routing act against that idea. And there are gaps at the galley, head, and hanging locker that would be difficult to carry through the idea.

In short - the boat could have been built that way in the first place, relatively simply. Retrofitting it could be a bit of a nightmare.

[Hardhead]

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.

[sailon46]

My Bene 51.4 Cyclades has a bow chain locker with only access from outside at the bow,,totally enclosed. Behind this 3-4 foot box, there is the crew cabin also with an impenetrable bulkhead, that is another 10 foot enclosure. The stern also has a bulkhead with a space of 6 feet to the sugar scoop. This design is duplicated to all the Benies oceanis etc.
FYI Ernie on the Mary Jane

[Red Sky]

Anchor locker and holding tank are forward of the water-tight bulkhead and an above waterline dam forward of the rudder post on my Caliber 40LRC.

[Dockhead]

Originally Posted by Lake-Effect

Our boat has a watertight, isolated lazzarette . Sort of like an airbag on a tricycle.

Nonsense. That is a Very Good Thing.

[KWISPEL]

There are also boats like the ETAP 38i, completely 'unsinkable' due to its double hull filled completely with closed-cell foam. The foam is completely attached to the hull (part of the structure), and still dry after 25 years. Even bigger bonus from the foam is that there is then no condensation (well insulated, bone-dry bilges), and also greatly reduced noise from outside (including from waves slapping against the hull). I love this boat, and have never understood why no other brands make boats in this way, and everyone is dealing with mold and condensation, etc. in the winter.
Greetings from a warm, dry boat with ice on the deck

[edmundsteele]

Originally Posted by S/V Illusion

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.

When on passage with our Amel, we would typically leave the door to the forward cabin open so that we could easily access the head. At sunset, we switched lifejackets to those with a strobe and harness, we switched instruments to night display settings etc. and we closed the water-tight doors. Our rationalization was simply that in a night-time collision, it would be easier to avoid confusion if this had already been done.

[noelex 77]

Originally Posted by S/V Illusion

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.

In our case the waterproof door works fine as a normal ordinary door. It has four stainless steel dogs, but these all close with a single lever. So the door can be be left closed without restricting easy access to the owners’ cabin

In the event of an emergency, with the door open it would take a great deal of water pressure to stop a frightened sailor closing the door and any water pressure from the most likely forward direction would be helping close, not open the door.

We can float with two of our five compartments flooded so in the very worse situation once the water level has stabilised, the door could be closed and the water could be pumped out from the undamaged section.

It is hard to allow for every contingency. Nothing is foolproof and our system is arguably overkill, but I think your suggestion that it is a: “feel good but futile option” shortchanges the safety benefits.

[thinwater]

Originally Posted by Dockhead

If you wanted the Kevlar for its structural properties, then perhaps it would make sense to put it in an inside layer. But remember resisting an impact may also involve preventing PENETRATION and a hull breach, and that is what the Kevlar is for, at least on my boat.

I had a Kevlar honeycomb boat that was impacted. The outer skin collapsed and cracked and the inside held quite easily in tension.



Yes, using Kevlar on the outside for impact is poor engineering. Abrasion I get.

[thinwater]

I've hit two objects large enough to cause damamge. Both were just below the surface and could NOT have been spotted by any watch. We went back and found both and exonerated the helmsman. They were invisible (dredge pipe, log) in the conditions. The rudder tube and shaft log would be my big concerns.

[s/v Jedi]

Originally Posted by noelex 77

It is hard to allow for every contingency. Nothing is foolproof and our system is arguably overkill, but I don’t think your suggestion that it is a: “feel good but futile option” shortchanges the safety benefits.

You are so diplomatic, it amazes me every time

My theory is that people who make such outrageous claims against a safety feature may feel insecure for not having it themselves and talk it down to calm their conscience.

Your setup is amazing and I wish my main bulkhead was like that

[S/V Illusion]

Originally Posted by s/v Jedi

You are so diplomatic, it amazes me every time

My theory is that people who make such outrageous claims against a safety feature may feel insecure for not having it themselves and talk it down to calm their conscience.

Your setup is amazing and I wish my main bulkhead was like that

Not too subtle personal attack noted - but misplaced.

We have 4 watertight doors and a number of watertight hatches so clearly jealousy or”insecurity” isn’t relevant here to my prior observation regarding the practicality limitation. If you derive a false sense of security from such a design, i compliment you on your optimism.

To review, every submarine which has ever sank had lots of water tight doors.

[s/v Jedi]

Originally Posted by S/V Illusion

Not too subtle personal attack noted - but misplaced.

We have 4 watertight doors and a number of watertight hatches so clearly jealousy or”insecurity” isn’t relevant here to my prior observation regarding the practicality limitation. If you derive a false sense of security from such a design, i compliment you on your optimism.

To review, every submarine which has ever sank had lots of water tight doors.

You have 4 watertight doors in your boat and think it’s useless and futile to prevent sinking? Well then, clearly I was wrong and offer you my apologies for my wrong conclusion

To get into the subject again: do your doors close towards the center of the boat? You state that one can’t move the door against incoming water flow, but as that almost always comes from either the bow or the stern, one would assume water flow aids closing of the doors?

[hpeer]

Thread title:

crash bulkheads on PRODUCTION boats.

While I would love a sun deer and especially a Bestever they are hardly production boats and rank among the elite. Lucky for you guys but to most of us that’s like arguing about whose car is better: Bentley or Rolls. Meanwhile I’ve got a beat up Chevy.