Length of Cat vs comfort/safety

[Seaslug Caravan]

Right on cue

Next.

[Dulcesuenos]

Comfort also has a lot to do with hull design and bridge deck design and clearance. Anyone who says otherwise hasn't spent considerable time on those boats in a variety of conditions. Our 38 Athena pounds much much less than has our 38 leopard which rode better and pounds less than a 42 and 46 leopard. The manta 42 rides nicely and with less hobby horsing than a manta 38 or 40 though all 3 ride and handle well. Certain boats can be heavy and extending the WL a few feet makes a difference in motion/ comfort. Boats with flared hull chines/ sides common on man production boats, catch waves which make a very bad smacking noise and also when the forward berths are over the bridge deck and its a lower bridge deck, the hull gets smacked a lot and makes sleeping forward tough while offshore. While all 4 are safe in anything but horrific conditions you just wouldn't want to be out in, I know which one is most comfortable for us offshore. The 46 is obviously much more comfortable at anchor lol.


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[SV DestinyAscen]

There are so many design variables that impact comfort and safety It's not so good to focus on length.

Like so many explained in the other catamaran thread, reserve buoyancy is really important to catamaran comfort, safety and performance.

In a properly designed heavy displacement monohull, it's a comfortable motion to plow through water. It's an awful feeling in a catamaran when it's overloaded. Since catamarans generally rely on thin beams for performance design, length is easier to improve volume and buoyancy. But you can take a nicely designed 45ft hull and then ruin its comfort and safety by exceeding design weight, then fudge it up by trying to increase sail area to compensate, then bulk it up more to compensate for forces on the rig - and the vicious cycle continues.

There's also noise, vibration, harshness to take into account - waves slapping a low deck makes a huge noise in the hull (like a sound amplification box). That's not length dependent.

[StuM]

Originally Posted by Dave_S

Sorry for the quick detour, what is a sugar scoop.

Thanks
Dave

The sloping bit incorporating stairs on each side at the back end of your boat.

[thinwater]

Originally Posted by StuM

The sloping bit incorporating stairs on each side at the back end of your boat.

Also incredibly useful for getting in and out of dinghies and kayaks. I added a pair to help my wife (knee replacement), since she was unable to climb around. Like having a floating dock at the back of the boat. There are many good reasons they have become ubiquitous on cats, and no down sides that I can see.

[tomfl]

Length is one factor, but beam is another. I have a friend with a Schionning basically the same length as my Seawind before the sugar scoop extension. While my beam is 19'5" his beam is over 23 feet; both for basically 10 meter boats. The two boats are more different than one might expect based only on length. Too many design considerations to really answer your question. I had an interesting exchange with Ian Farrier at SA about design where he claimed, and I agree, that many "cruising cats" suffer from their transoms dragging in the water. The extra length of my sugar scoop extension make a huge difference not only in comfort and sea kindliness but speed as well.

The key no matter the boat length is a good design.

[sparau]

Originally Posted by barnakiel

Same for same, bigger is more comfortable.

But this must be same for same.

I have sailed a Schionning 54 that was way less comfortable than a Privilege 37. They are vastly different and cannot be compared 'for size'.

Etc.
b.

Hi Barnakiel,

Would you mind commenting further on that?

I would have thought the finer hulls and 17' of length would have mellowed out what is a much lighter boat foot for foot.

I take it you were in cruise mode with both boats in roughly similar conditions, what was uncomfortable about the Schionning's motion?

Cheers
Shane

[FSMike]

Originally Posted by Seaslug Caravan

-----
Chris Whites reaction to the capsize of the 17M Anna, was to come up with a small ineffectual schooner rigged wing sail arrangement, with a low CofE, in the hope it wouldn't happen again.
-----

Gee, that was Chris White's reaction?
"ineffectual"? I didn't know that either. How many miles do you have on one of those boats?

[smj]

Originally Posted by tomfl

Length is one factor, but beam is another. I have a friend with a Schionning basically the same length as my Seawind before the sugar scoop extension. While my beam is 19'5" his beam is over 23 feet; both for basically 10 meter boats. The two boats are more different than one might expect based only on length. Too many design considerations to really answer your question. I had an interesting exchange with Ian Farrier at SA about design where he claimed, and I agree, that many "cruising cats" suffer from their transoms dragging in the water. The extra length of my sugar scoop extension make a huge difference not only in comfort and sea kindliness but speed as well.

The key no matter the boat length is a good design.

Your right Tom, the stern extensions on the Seawind 1000 completely transform the boat. Better speed and a much better motion.....which translates into better speed! Funny how some Seawind owners don't take advantage of this transformation, as the cost to me to have it done is minuscule compared to the benefits.


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[valhalla360]

All else being equal, yes longer and wider is faster and more comfortable.


Of course, all things are never equal.

[tomfl]

Originally Posted by valhalla360

All else being equal, yes longer and wider is faster and more comfortable.


Of course, all things are never equal.

One of the things not being equal is longer AND wider. Just because a boat is longer does not mean it is wider and conversely just because a boat is wider does not mean it is longer. Same goes for bridge deck clearance, just because a boat is longer does not mean there is more bridge deck clearance.

[44'cruisingcat]

Originally Posted by valhalla360

All else being equal, yes longer and wider is faster and more comfortable.


Of course, all things are never equal.

Even simply making a boat longer will make it faster and more comfortable. Faster, because it will pitch less, and present the sails better, and more comfortable also because it will pitch less.

[Dulcesuenos]

Just because brand L is longer and wider than Brand F doesn't mean it handles better or more comfortably.
Hull design and bdc has more to do with it. Were not talking monohulls here. All longer cat that drags its bridge deck over every wave is going to be considerably slower and less comfortable than a smaller cat with better clearance and design.

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[Dulcesuenos]

Meant "a " longer cat

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[KJThomas]

As my Wharram capsized, twice! On its mooring, as well as not being able to sail to windward well enough to get out of trouble, I would dispute the claims for being safer than more modern designs.
Needless to say, i no longer own a Wharram.
Surprising what you can sell with a few naked bodies