Multihulls that don't slam

[zboss]

I have had recent experiences on two catamarans (A leopard and a gemini) and they both had a hard slamming bridge deck in 2-3' seas.

Are there ANY cruising cats that don't slam? Its quite unnerving and I find myself less and less interested in cats as a result.

[Sailmonkey]

Neither one of those is what I would call a cat with adequate bridge deck clearance.


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[monte]

I wouldn't say ours Lagoon 400 has never slammed, but I can honestly say I've never noticed it slam or been bothered by the occasional waves slapping the bridgedeck. Same goes for the Lagoon 380. We've sailed both from France, Atlantic Europe Coast, med, Atlantic, Caribbean, about 10000 M, upwind, downwind, upswell, across and down swell, waves up to 6m but we usually try to sail when the forecast is under 3m. I'm usually more concerned when I sail a mono and I hear the rig groan and creak as she is hit by a gust. Maybe fat wide lagoon hulls help with vertical stability, as opposed to narrower hulls, I don't know. I'd think leopard would be similar, but from memory some do have quite low bridge decks. Same goes with the Gemini. I think I've heard owners complaining about geminis slapping at anchor.

[Red Herring]

I am curious as to which leopard you were in?

[RTB]

Originally Posted by zboss

Are there ANY cruising cats that don't slam? Its quite unnerving

I sailed with i2f to Colombia, and we had a few "bombs" go off even on Imagine. A 46' Simpson with a lot of bridge deck clearance.





It is quite unnerving (VERY LOUD) if you aren't used to it, I guess. Being a mono guy, I would steer as high as possible, but John would come and turn down some. It would usually quiet things down. It just depends on conditions and point of sail.

Ralph

[snort]

This one:

[zboss]

Originally Posted by Red Herring

I am curious as to which leopard you were in?

410. I've also been in a 380 that did not slam but was only a charter so it did not have all the weight of a cruising vessel, like a wind generator.

[valhalla360]

We have a Gemini. Yes, if you try to run straight into 2-3' chop, she bangs away. Never heard of it causing a problem but definetly gets on your nerves. Bear off a bit and the problem largely goes away.

In most other conditions, it's not really an issue. With a big swell, you can get quite large waves and it's not an issue. Any kind of reaching or running and it's never been an issue regardless of wave size.

The only time it's really an issue is if you get a short chop in confused seas so you don't have a good option to bear off. If you are going thru a busy area with lots of boats throwing wakes from every which direction, that's when it gets annoying.

Of course, the benefits of all that space and a stable platform at anchor are more than worth the minor annoyance.

[mikereed100]

As has been mentioned on these threads before, there are many variables involved in what makes a cat slam. Height of the bridgedeck is one, but the buoyancy of the hulls and the hull spacing are equally important. All cats will pound given the right circumstances but a boat with high bridgedeck, narrow tunnel and wide hulls will pound much less than a boat with low bridgedeck, wide hull spacing and narrow hulls.

[thinwater]

Very rare in PDQs... but there is a compromise.

The PDQ 32 (similar in size to the Geminis) has a slider that opens under the hard top in order to get standing headroom on the bridge deck, without having to look through 2 layers of windows, like the Gemini. Thus it is more fun to sail to windward in slop, but you get to stoop if it is cool and the slider is closed. The hard top provides enough coverage that the slider can stay open in virtually all weather, including rain. There is also one more step down in to the hulls on the PDQs, because the clearance is higher.

The PDQ 36 does not need the slider because it is just a little bigger.

There is no magic, only compromises.

[zboss]

Originally Posted by mikereed100

As has been mentioned on these threads before, there are many variables involved in what makes a cat slam. Height of the bridgedeck is one, but the buoyancy of the hulls and the hull spacing are equally important. All cats will pound given the right circumstances but a boat with high bridgedeck, narrow tunnel and wide hulls will pound much less than a boat with low bridgedeck, wide hull spacing and narrow hulls.

and that boat is....?

[Dulcesuenos]

We were going to get a mono, but couldn't find one that didn't heel,
Seriously though its all a compromise, our leopard 38 rarely slammed ever. We would get an occasional slap if a wave hit the inner side of the hull. Our athena not at all. Compared to bobbing and swaying and rolling at anchor, ilk take a little bridge deck noise any day.

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[mikereed100]

Originally Posted by zboss

and that boat is....?

Ahh. I forgot you were looking for specific boats. My boat is a custom design that I completely redesigned, so I guess you could say it is custom^2. It has relatively high bridgedeck clearance and fat hulls and the bridgdeck has never, as yet, slammed. The tradeoff is that we don't have the high top end speeds that a cat with narrower hulls would have. As Thinwater says, compromises.

[REsCat]

As I have remarked on the many previous threads on this subject... "ALL" Cats generally talked about or cruised on in this forum will pound/do pound sailing into a 20 kt+ wind short chop or confused seas etc. Obviously Cats that have higher, smooth bridge decks will probably pound less... but they will still pound at some point in those conditions.
Anyone who says or claims otherwise has never left the dock OR sailed in the above conditions OR has some entirely different concept of pounding/slamming that the majority of people on this forum agree on...
Monohulls will slam/pound occassionly in the above conditions...the same rules above apply.
I am continually amused by claims like such above....

Bob

[dirkdig]

Our Lagoon 440 has 650mm of bridgedeck clearance.
Going head on into seas of about 25 knot winds we get a little slamming, once 20 deg plus off that it drops right off.
Wide buoyant hulls with that clearance works.


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