what happens if you hit a rock?

[onotoa]

in the marina where our boat is on the hard now i saw a sunfeef 70 cat with a hole in the keel, about 30x15cms
i was told that the boat semi-sunk, just the roof was out of the water. through that hole you could see the inside of the boat, there was no watertight compartment.
i think thats one of the most sensitive points (the front) of the boat so i dont understand the construction - is that normal??

on our boat the blackwater tanks are in the front so i think that cant happen to me??!! how about you??

helmut

here is the link to the boat:
http://www.sunreef-yachts.com/model-exterior,Single-Deck-Catamaran,3,Sunreef-70.html

[ireaney]

I thought that a lot of the keels were semi sacrificial, in this case it appears not, a bit scary.
If the keels were made to be used as water tanks or holding tanks, surely they could still have sacrificial keels and water tight seals between the bilges and top of the keels.
Then again, best bit of advice, don't hit any rocks.

[smj]

In my opinion the keels should be attached after the hull is laid up. We hit a rock in our Cherokee 35. When I dove on the boat I could stick my fist and arm into the keel. We sailed from the Fl. Keys back to Texas like that and hauled out and repaired a few months later. Good design.

[Maxingout]

One of the things I like about our Privilege 39 was that the first six to eight feet of the keel was totally sealed off from the hull. You could knock a hole in the keel without ingress of water.

I saw a Privilege 48 in New Caledonia that had ingress of water because they went on a reef. In that case, when their rudder came down on the reef, it punched the rudder through the hull. That flooded the engine room and that side of catamaran. They salvaged it so it lived to sail once again.

[Talbot]

The Catalac does not have a LARS keel but does have a vulnerable skeg. This is attached seperately, so that if you do damage it, you should get away with it. If it gets puched up into the hull, it is also in a small watertight compartment, so again should be all right.

[2hulls]

Keels? Keels are for monos.

[Talbot]

Originally Posted by 2hulls

Keels? Keels are for monos.

I think you will find that most multis these day (except for the sporty types who like to fiddle with dagger boards) are actually fitted with wat are known as Low Aspect Ratio keels - this was initially done by Prout, and has been significantly shortened in newer designs in order to reduce the wetted areas, but the concept is the same.

[Nordic]

2Hulls has daggerboards

What happens when these hit a rock at speed?

[onotoa]

so you guys tell me that this could just happen to a multimillion €€€$$$ yacht and not to -normal- small cats??
so there is something wrong with the sunreef design....

[Nordic]

This should not happen to a well designed boat, luckily many if not most production cats are not designed like this.

The best keel design I have seen is probably the Leopards, where the keels are actually sacrificial, and can be replaced.

The fairing of the underwater lines on the last picture you posted doesn't look very nice IMO.


Alan

[Sandy Daugherty]

Finally there's a topic I can brag in! My PDQ 36 has foam core above the waterline, sacrificial keel extensions, and the rudders are in a separate compartment so that severe damage to a rudder does not introduce water to the living area.

Each hull was molded in two halves and joined at the centerline so that there is a very strong structure running the length of the hull. There are shallow keels in the hull mold, to which are attached sacrificial LAR keels, for two advantages: the bottom of the keels can be completely ground off and the boat will remain water tight, but there is still a step-down area in the bilges where incidental water (from an open hatch or a burst water line) accumulates to be pumped out. This boat could really take a beating.

To top it off, the foam core, huge airtanks, and very light engines means that you could very possibly fill the boat with water and still sail it. SLOWLY.

[Maxingout]

Originally Posted by onotoa

in the marina where our boat is on the hard now i saw a sunfeef 70 cat with a hole in the keel, about 30x15cms
i was told that the boat semi-sunk, just the roof was out of the water. through that hole you could see the inside of the boat, there was no watertight compartment.
i think thats one of the most sensitive points (the front) of the boat so i dont understand the construction - is that normal??

on our boat the blackwater tanks are in the front so i think that cant happen to me??!! how about you??

helmut

here is the link to the boat:
http://www.sunreef-yachts.com/model-exterior,Single-Deck-Catamaran,3,Sunreef-70.html

I'm looking at the fiberglass exposed in this disaster. I question the quality of the layup. It looks like a dry layup to me with incomplete saturation of the glass with resin. Am I missing something?

[lhsmith]

A little out of place here, but I was told at the Annapolis boat show that the keels on the new Leopard 38 are an integral part of the hull, not bolt-on sacrificial keels. I don't know what R&C may have done to ensure that keel puncture doesn't lead to hull flooding.

[Yoga O]

Dave,

Good question, but probably a bit hard to say from this pic given we don't know how long the boat was bashing into the rock or how long it has been subsequently laid up drying out.

Nordic,

Hopefully if you hit something w/your daggerboard 'at speed', the board will break away before the daggerboard trunk cracks open.

Fair Winds,
Mike

[Nordic]

Hopefully is the key word The daggerboard casing is "hopefully" bult like the proverbial brick ____ house.

I have seen a casing that was too weak, a major repair job as the board had somehow twisted with major damage to the sides of the hull as well.

Alan

[onotoa]

@ yoga o + nordic: i think the boat is a total loss, it was three days flooded and now its sitting on the hard for a month and nothing happens to recover it....if you wanna own it you maybe have to discuss with the insurance company??
helmut

[BigCat]

Originally Posted by smj

In my opinion the keels should be attached after the hull is laid up. We hit a rock in our Cherokee 35. When I dove on the boat I could stick my fist and arm into the keel. We sailed from the Fl. Keys back to Texas like that and hauled out and repaired a few months later. Good design.

Boats with integral keels should use them as tanks, preferably for blackwater, so that you don't lose anything valuable or extremely harmful to the environment in the case of holing. I don't think it matters how they were built as long as they are sealed off with glassed in tops. This story is an example of why I favor the 'Wharram' type of cabin design, in which there are multiple watertight compartments in the hulls, with access to each cabin through the bridgedeck or hull decks. Even the smallest catamarans should have a minimum of three watertight compartments per hull. BigCat 65 has five watertight compartments per hull.

[Yoga O]

Originally Posted by Nordic

Hopefully is the key word The daggerboard casing is "hopefully" bult like the proverbial brick ____ house.

I have seen a casing that was too weak, a major repair job as the board had somehow twisted with major damage to the sides of the hull as well.

Alan

Agreed, I know of a CW that hit 'at speed' and ripped out the trunk. Of course, it also hit a very shallow rock and then drove up on the hard, so you can't be 100% certain that the trunk failed because the board was too strong.

OTOH, we had one of our boards snap off in Chesapeake Bay 3 - 5' chop. It appeared to have a layup problem and was replaced @ n/c by Maine Cat. Man, was the new one BIG when it arrived in a crate.

Fair Winds,
Mike

[2hulls]

Originally Posted by Nordic

2Hulls has daggerboards

What happens when these hit a rock at speed?

I imagine they would break. But I wouldn't be breaking the hull and inviting the ocean in.

Point >> don't hit a rock or coral head or anything else you can reasonably avoid. Stuff bobbing just below the surface is what concerns me..........

2 Hulls Dave

[lhsmith]

Yeah, like shipping containers and blue whales.... Does anyone know of a a website that tracks losses from ships? I am aware of an oceanographer in the NW US who uses spills to help model surface currents in the Pacific, but his focus is on the currents.