Multihulls that don't slam

[jaybird1111]

Is there such a thing as a monohull that doesn't heel or roll?

[monte]

I agree Bob. Heading directly into a short period sea is the worst conditions on any yacht or powerboat, and the sensation is pretty much the same for mono or multi. A lot of pitching and slamming of the hull into the waves. Fortunately the waves are usually coming downwind so tacking to windward will put them on at least some angle. I can't understand why some yachts motor upwind to their destination. It's always less comfortable than sailing and rarely any faster. Often we are tacking comfortably upwind and watching yachts motoring along the rhumb line directly upwind, bows lifting 3m on the peaks and slamming below the surface in the troughs. I just don't understand why they bother in most cases..

[boatman61]

Definitely gotta take some Cat sailing lessons...
For me they slam going into the wind.. and man.. the bangs on the leeward hull in any course with a decent sea 45 degrees either side of the beam is boat shakingly scary.. but then again I deliver em.. not cruise em with the luxury of being able to wait till its 'Just Right'..

[zboss]

Originally Posted by jaybird1111

Is there such a thing as a monohull that doesn't heel or roll?

Thats not the basis of my question. We have been interested at purchasing a cat, particularly a larger Wharram, but in my experiences thus far the slamming of the cats I have been on has been a real turn off. I'll take heeling or rolling over slamming any day.

I have not yet found a Wharram to sail so I am hoping to come across one at some point to see if my interest is well founded. The open bridge deck, would seem to result in less slamming.

When people claim their cat doesn't slam I wonder if this is when they are fully laden for cruising.

FWIW... my Cabo Rico doesn't slam under any conditions, even fully laden with full water, fuel, and all our provisions/beer for three months in the Bahamas.

[Canibul]

Well, what's your question? The one you chose for a title, i.e. "Multihulls that don't slam", or is it what you wrote immediately thereafter which is about catamarans specifically?

If the former, then the answer might be "Yes, there are multihulls that don't slam. They are called trimarans and proas."

If your question is specific to catamarans, the answer is "No. There are no production catamarans similar to your two examples with unprotected bridgedecks that are immune to the effects of being slapped by waves."

There are catamaran designs with nacelles in the middle of the bridgedeck, which some designers have tried for various reasons. I suspect the slamming is different with a nacelle in the middle between the hulls, but a bridge deck is a bridgedeck. Slap it, and it makes a noise. Duh.

I like the noise. It's nicer than a fog horn and keeps the monohulls away from me in the anchorage at night. Sometimes you can get a good Gene Krupa kinda beat going between the wave slap and the halyards...and the vibrations keep the barnacles away and knock off all the slime from the ICW.

[mikereed100]

Originally Posted by REsCat

I am continually amused by claims like such above....

Bob

Bob,

It is a fine thing to be amused, but better yet to be enlightened. We have sailed numerous times to windward in 20+ knots without the bridgedeck pounding. That is not to say the experience was not miserable. Those same fat hulls (8.5:1 Length:BWL) that keep the bridgedeck from slamming will themselves slam miserably until we either bear off or heave to. In other conditions waves will slap the insides of the hulls with a sound like hitting a log. Makes it hard to sleep, but again, not bridgedeck slamming. I have no doubt that at some point we will encounter conditions that will cause slamming on the bridgedeck but, as yet, after over 10,000 offshore miles, we have not.

[monte]

Here's a little extract from a recent blog entry that may be pertinent to the topic..

Sleeping on a boat...
Last night after my watch I lay down in bed and found it a bit difficult to fall asleep. The motion of the boat was a bit off and the swell at an odd angle. As I lay there I tried to imagine how to explain the experience to someone who hasn't felt it before, so here goes...

It's a bit like laying in a waterbed, but the bed is moving so imagine a irritated bear laying next to you rolling and turning and trying to get comfortable, all the while rolling and turning you. It's like your muscles have to work constantly just to lay still. Laying on your back can help or stuffing pillows under your stomach to spread the pressure.
Now imagine four dwarfs holding up each corner of the bed and lifting and lowering each corner 20-30cm randomly. The dwarf near your head has a strange sense of humor and slaps his hand hard on the wall next to your head at irregular intervals. Sometimes 30 seconds between, sometimes longer, but always when you least expect it.
Now for the sounds... Imagine another three drawfs with water utensils. One has a bucket and cup and continuosly dips the cup in the bucket and pours the water back in from varied heights. Another has a couple of water bottles he likes to shake close to your ears and the third drawf jumps up and down in child's inflatable swimming pool.
Add to those sounds the dull whine of the autopilot keeping us on course, assorted creaks and groans as Sephina twists and turns over the swells, and the occasional surfing sound which is kind of like driving fast down a gravel road and you get an idea of what it's like to fall asleep on a 40' yach mid Atlantic.
Sometimes these sounds are covered over a little by the dull sounds of the Diesel engine if there's not enough wind or if the batteries need topping up till the sun shines on the solar panels.
So while laying there imagining this strange twisted fairy tale of creatures around me I drifted off and had a deep long sleep, dreaming of goldilocks, Snow White, red riding hood or some other strange concoction put together in my sleep by the sounds and motions as I slept...

[Thenaz007]

I sailed a leopard 43 in very brisk winds (1 reef) on all points of sail and never noticed anything. Topped off and 5 aboard but a charter. In my mind high freeboard is unavoidable with underdeck clearance - are their people out their who feel like they are getting blown around docking in close quarters? Everything is a compromise. If I stay light, patiently wait for weather windows, and stay in the coconut run I think I would be fine in a Gemini?

[rfadler]

Originally Posted by zboss

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.

410 would typically be a Lagoon.

[monte]

Yep high freeboard and windage is a trade off. Fortunately we only dock a couple of times a year, but maybe with more practice it would become less nerve wracking. I guess it's what you get used to. Not all higher bridgedeck cats have high windage, but some compromise would be made in internal accommodation.

[Cheechako]

Yes, the ones with one hull.....

[REsCat]

Originally Posted by mikereed100

Bob,

It is a fine thing to be amused, but better yet to be enlightened. We have sailed numerous times to windward in 20+ knots without the bridgedeck pounding. That is not to say the experience was not miserable. Those same fat hulls (8.5:1 Length:BWL) that keep the bridgedeck from slamming will themselves slam miserably until we either bear off or heave to. In other conditions waves will slap the insides of the hulls with a sound like hitting a log. Makes it hard to sleep, but again, not bridgedeck slamming. I have no doubt that at some point we will encounter conditions that will cause slamming on the bridgedeck but, as yet, after over 10,000 offshore miles, we have not.

Mike.... With all due respect.... For all the sailing miles, experience, conditions that you detail above... day or night....have you (or can you?) continually watched the wave conditions and interaction with your bridgedeck underneath, or "fat hulls" and the resultant bang,slap, pound... what ever you want to call it!
Can you honestly say that your bridgedeck has never slammed with an errant wave or cofused sea condition????
I am pretty sure my bridgedeck clearance is probably as high or higher than yours and I have logged similar if not more miles and I could never make that claim.
I know I have "slapped, banged, pounded" with some part of my bridgedeck or hulls at some point (sometimes have observed it...) during the miles and have cringed on the thankfully few "bone crunchers" and been glad that my hull construction/design is pretty robust so far.

I also cannot understand a claim that a monohull, be it loaded or empty has never fallen off a wave, or tangled with confused seas, chop and suffered a "bang,pound,slap,crunch" ???
I have logged offshore miles on Swans, Tartans, Hughes to name a few and they were not immune to the above conditions....

Bob

[Highland Fling]

I am quite CAT experienced had 27 knots out of a Cantana 471 at the Miami boat show once.....the salesman kept easing the Genny sheet so I kept bearing away...lots of water and a few screams from the other punters on board, a few who though being in the bow seats was a good idea....

BUT I digress most of the many cats I have sailed on HAVE SLAMMED.....

BUT Amazingly the Lagoon 420/421 does NOT SLAM........

How do I know this?

Well I was a Hired Gun (helmsman) at the recent 35th 2015 St Martin Heineken Regatta.

We had BIG BIG SEAS BIG SWELL and lots of CROSS SEAS and SWELLS

and YES we were going to windward in up to 35 knots of wind.

TWICE I put the bows right under a big almost vertical wave that ended up in the cockpit soaking the crew THREE WONDER WOMEN!!!

BUT AT NO TIME did I notice the L 420 slamming I WAS SERIOUSLY and GENUINELY AMAZED.

We got a third in class (only a third) mostly due to constant riding turns (almost every time we tacked) and once I screwed up big time, as I thought I was helming Highland Fling and passed the windward turning mark with about 18 inches of clearance put the helm down and moved sideways into/onto the mark.

Doing the 360 was a real PITA as the L420 would not tack at low boat speed and we lost about 15/20 minutes doing the 360 and binned a possible first place. We were racing hard but on an overweight well over loaded cruising L420 catamaran.

BUT in Five races with a lot of windward work in very heavy weather the L420 never slammed ONCE.....probably due to the central gull wind bridge deck configuration.


With a light ship and with feathering and or folding props I think the L420 could/would be a rather / very nice cat, and I am a L440/L450 and Leopard 46 fan.....maybe one day we will move to the dark side but not very soon I suspect.

[Tom and Maje]

We have a 2014 Leopard 40. Yes, she slams, but not in 2-3 seas. The plan fact is that you're either going to be slamming or heeling.


Maje

[Wendi]

Originally Posted by monte

Here's a little extract from a recent blog entry that may be pertinent to the topic..

Sleeping on a boat...
Last night after my watch I lay down in bed and found it a bit difficult to fall asleep. The motion of the boat was a bit off and the swell at an odd angle. As I lay there I tried to imagine how to explain the experience to someone who hasn't felt it before, so here goes...

It's a bit like laying in a waterbed, but the bed is moving so imagine a irritated bear laying next to you rolling and turning and trying to get comfortable, all the while rolling and turning you. It's like your muscles have to work constantly just to lay still. Laying on your back can help or stuffing pillows under your stomach to spread the pressure.
Now imagine four dwarfs holding up each corner of the bed and lifting and lowering each corner 20-30cm randomly. The dwarf near your head has a strange sense of humor and slaps his hand hard on the wall next to your head at irregular intervals. Sometimes 30 seconds between, sometimes longer, but always when you least expect it.
Now for the sounds... Imagine another three drawfs with water utensils. One has a bucket and cup and continuosly dips the cup in the bucket and pours the water back in from varied heights. Another has a couple of water bottles he likes to shake close to your ears and the third drawf jumps up and down in child's inflatable swimming pool.
Add to those sounds the dull whine of the autopilot keeping us on course, assorted creaks and groans as Sephina twists and turns over the swells, and the occasional surfing sound which is kind of like driving fast down a gravel road and you get an idea of what it's like to fall asleep on a 40' yach mid Atlantic.
Sometimes these sounds are covered over a little by the dull sounds of the Diesel engine if there's not enough wind or if the batteries need topping up till the sun shines on the solar panels.
So while laying there imagining this strange twisted fairy tale of creatures around me I drifted off and had a deep long sleep, dreaming of goldilocks, Snow White, red riding hood or some other strange concoction put together in my sleep by the sounds and motions as I slept...

Wow, I am still laughing. Brings back memories. This is a very accurate and amusing description of how it feels to sleep in the cabin. I always enjoyed that sledge hammer that was being slammed to the hull next to my head. That was in a wonderfully orchestrated concert with all of the above dwarfs and sounds described. Those last 6 days were relentless. 18' seas and squalls to keep me humble. But the noises, oh the noises.
There were the beautiful silent nights of smooth seas and the only sound is the breath of the dolphins who have come to swim alongside. It is all worth it.