Sinking Cats

[James Joll]

Here is part of a mates email from Phuket.
Have had three cats nearly sink here in the last week . Friends of ours hit somthing and bent rudder back up into the hull of their sea wind. Had to beach it on a reef, filled one side up over the motor, and right through that hull. Safe now back up on the hard again for major repairs. The other was a Lagoon 500 six months old. Caught a thick dingy warp around prop when reversing, and pulled sternleg off. Managed to beach it, but still filled up one side. Havent heard what the other one was.
Food for thought !!

[Southern Star]

Thanks James for getting us back on the track of this thread - sinking multihulls, rather than how to right them in the unlikely event that they capsize. Once again, it speaks to the advantage of both fore and aft watertight collision bulkheads - something that is generally lost when diesels are placed well aft in the hulls, so that they can be accessed from on deck. To me it is still the best argument in favour of installing diesels under the aft berths - less convenient (unless you need to perform maintenance in heavy seas or inclement weather), but far more safe.

Brad

[Joli]

Don't know what this one was but they arrived at night wanting to see the donkey. Missed the opening and were towed off the rocks and beached that morning. They had some big pumps running, would it have sunk sunk? I don't know but they did not waste any time getting it off the rocks and on the sand beach.

[captain58sailin]

With regards to the self righting abilities of a lifeboat, I would think, you could find CFR 46, helpful for the specifications, of course that would only apply to U.S. inspected vessels.
As to righting a Cat at sea, it seems like years ago, I heard something about installing an inflatable unit on the mast head used in combination with a sea anchor a Cat could right themselves.
The "Titanic" is proof, that the most dangerous thing on a vessel is the owner.

[paulrack]

In response to Southern star. You actually do not want the motors under the bunks as most cats have drawers or cupboards at the front of the bed which means it is not sealed from the rest of the hull. On my cat the motor is in a separate aft compartment, If I lose a saildrive the worst that can happen is that it can only flood that one compartment.

[Eleven]

Mine too has the motor under the rear deck. Well above the water line and in a separate water tight compartment that might take splash if I lost the drive leg, but would empty quickly too.
There are water tight compartments in both bows and high in each stern. Though I suspect that a holed hull would still flood the whole boat and in another thread I've read of the surge of internal water ripping all stores out of compartments and mixing thoroughly.
Would it sink? I doubt it. But repairing it fit to sail, and surviving on damaged rations, and polluted water would definitely be limited to a few days.
Secure water storage seems a basic, in nice plastic jerry cans of tap water that will string along behind the liferaft/dinghy seem the only last option for the blue water cruiser. No food, still able bodied after three to four weeks. No water, about four days.
So make sure your cat has bouyancy, and the water tanks are safe in most conditions, including inverted, with all top entry pipes run to the bottom, and the air vent run down to the bottom and back up again to above tank top. The diesel tank too should have the same so nothing runs out no matter how the tank is tipped.

[Southern Star]

Paulrack, most cats with diesels under the bunks do not have drawers under them (precisely because the space is occupied by the diesel/transmission/saildrive); and, while they are open at the top, mine are sealed from the rest of the interior and have separate bilge pumps. Tearing out a saildrive would allow water to access the engine compartment, as in your boat, but not sufficiently to rise above the bunks (which are actually slightly above bridgedeck level). Fruthermore, since the water intrusion would be more centralized (again, as my diesels are mounted further forward and there would still be floatation aft of them), the boat would also tend to sit a little closer to her original lines.

Brad

[Tropic Cat]

I agree with Talbot. Buy the boat with a record of never lifting a hull under any circumstances.

[cat man do]

Originally Posted by James Joll

Here is part of a mates email from Phuket.
Have had three cats nearly sink here in the last week . Friends of ours hit somthing and bent rudder back up into the hull of their sea wind. Had to beach it on a reef, filled one side up over the motor, and right through that hull.

I did the same once, hit bricks and bent rudder back punching a hole, just.

Would not have mattered as I had a watertight BH (2 actually) there for just that purpose

Caught a thick dingy warp around prop when reversing, and pulled sternleg off.

Stern leg?



or sail drive



I suspect it was the latter and wouldn't it have just torn the leg off?
It is jointed, so I suspect that it is designed to break before tearing the vessel apart.
Wouldn't the surrounding area that the leg goes through have been sufficiently reinforced so as not to tear out?

[cat man do]

Originally Posted by Tropic Cat

I agree with Talbot. Buy the boat with a record of never lifting a hull under any circumstances.

Building one now
though it will lift with a crane, does that count?

[schoonerdog]

I like this conversation, people should focus on things like adequate structural bouyancy as a safety requirement for any boat they would personally own. By that we mean bulkhead with no penetrations that run intact from the bottom of the hull to far above the waterline. Many production boats which are meant for charter simply have births in these spaces and will sink like a stone, especially since they start life as some of the heaviest catamarans. Personally I like a crash compartment inside the water tight compartment that acts as a floor of these spots to contain water even further and for that space to be filled with empty 2 liter plastic bottles filling that space (rather than foam) and a large pvc pipe going from an inspection port down to the bottom of the compartment to look for and remove water with a waterpump. The 2 liter bottles can be removed if need be easily to access the inside of the hull while foam can't (and tends to absorb water over the years). Also, please consider a hull breach an inevitability and create an emergency bilge pump. I've got a rule 1500 GPH bilge pump with a 12v adapter plug, 40 ft of wire, and 20 feet of exhaust hose to go out the nearest hatch. In the 10 years that I've been permantly living aboard boats I've used it numerous times. Just two weeks ago when we had 2 feet of snow fall in 24 hours that added around 20,000 lbs of weight to the boat I had an unchecked through hull that was normally a foot above the waterline become a steady stream of water coming into our forward watertight compartment at 4am. It was really good at the wee hours of the morning to cork up the through hull and stick that pump in the compartment to empty it out in a matter of a couple minutes. It's super simple to rig up and it will save your boat or your neighbors boat. Regular bilge pumps are meant to keep the bilges dry, not compensate for an emergency, and they often are sitting there with their float stuck in place or burned out and not working because, well, they are sitting in the bilge. Make one today if you don't have it.

[Tropic Cat]

4AM? Snow? 20,000 lbs?

There's room at my marina..........

[fastcat435]

sailing is all about safety, first we have a bow that can be damaged with out worry and is replaceable that is put in front of the safety bow, we standard build 2 crash bulkheads in to both bows, 1 is 500 mm from the front bow from top to bottom, the second compartment is a 1500 liter from the first crash bulkhead horizontal to the main bulkhead.
In the stern's we have a crash bulkhead 800 mm from the stern sealed and below the rear bunk we have a closed flotation chamber of 1800 liters of air each side.
Besides that we have several foamed areas in the boat to increase buoyancy and we use Divinycell foam true out that has over 5.5 tons of buoyancy. with a total loaded boat weight of 8 tons and more than 16 tons of buoyancy it will never go down.
We use no more inboard engines so no hull penetrations there just outboard Green Motion electric drives.

[s/v Jedi]

hmmm 8 tons loaded total weight? We already take 4 tons in fuel and water. With 8 tons, how much of that is for stuff the crew takes aboard? Dinghy, outboards, scuba gear and there's another ton....

Water tight bulkheads should be fitted into every boat. One forward for the crash that doesn't really happen so often plus the important one in the stern where rudder(s), prop-shaft(s), raw water circuits/pumps etc. all lead to failures and cause sinkings regularly.

cheers,
Nick.

[fastcat435]

I am sure with a 60 ft Monohull you could take 4 tons of fuel and water but why, you have a sailboat so that is your main propulsion, having 500 liters of diesel should be sufficient.
regarding water a water maker weights a lot less than tons of water so that is the way we sail, we normally sail with 200 liters of diesel ( for emergency only with the electric regenerating motors) and 200 liters of water, cats are more weight sensitive than mono's but loosing weight always helps .