Faster Catamarans have a much less comfortable ride

[GaryJones]

This is a very YouTube hyperbole rich, emotive title so apologies for that. It is a direct quote from:

https://youtu.be/LC8Q4oN2kjs?t=643

Having only sailed a couple of monos but dreaming of a performance catamaran I wondered how true this was?

Is his experience mostly from performance catamarans being sailed to 'impress' and hence going quite quickly compared to other catamarans and this is what caused the motion or is it just a fact that being lighter means less inertia to overcome and you follow the waves more easily and that creates a greater motion which in term is more tiring and perhaps more 'uncomfortable'?

If this is true, do you get used to it?

I assume people like 44c don't have a problem living aboard what is probably one of the lightest and fastest boats on the forum so are they compromising on a comfortable motion to do so?

[rslifkin]

No real cat experience to draw from, but I'd expect the ride to be a bit more like a planing hull powerboat. Not necessarily more motion, but faster, sharper motion (especially at higher boat speeds), and a bit more of the bobbing like a cork feeling. Depending on your preferences and what you're used to, you may or may not find it uncomfortable.

[Tupaia]

A lot depends on the conditions and the boat speed.

It is very difficult to compare apples with apples.

Because a lighter cat will sail faster in lighter winds the apparent wind will be bought much further forward and appear stronger. So if both cats are sailing at the same speed say 6 knots the lighter cat will be beating in 7-8 knots of wind whereas the heavier cat will be on a reach in 10-12 knots of wind.

You can see from this that it is very difficult to compare the noise and motion of two very different cats sailing at the same speed because the conditions will be different. If you compare them in the same conditions the lighter cat will appear noisier and less comfortable because it will be sailing so much faster than the heavier cat.

In storm conditions a heavy cat will sort of hove to, but because of it's weight will be slammed into by the waves and the noise will be greater. The lighter cat is unlikely to hove too in the traditional sense because of the inherent tendency to accelerate very rapidly and will end up fore-reaching, but will not resist the waves and be pushed away which will quieter but arguably more jerky for the occupants.

[CarlF]

If you've always been sailing mono's definitely sail on some cats before switching.

A 45ft cat will always beat a 45ft mono - but it gets really tricky when you compare mono and cruising cat not on length but on price.

I looked hard at a mid 40's cruising cat but ended up with a 55' mono with more accommodation space for the same price.

The long waterline on the 55' mono does 8.5 knots day in and day out - all with a lovely motion that makes you smile at the wheel. Too often, a cat feels a bit like sailing a marina float. You look at the instruments and you're making good speed - but it doesn't feel like sailing.

In the end, it's "different strokes for different folks"

[Chotu]

Hull shape comes into it on performance cats. A reverse bow and narrow hulls creates a super soft ride because it absorbs a little bit of the initial acceleration. Sort of like a suspension system in a car. It absorbs the rattling shocks but not hitting whoops.

As does a heavy cat, although it won’t be going too fast to begin with.

A cat motion is a lot like a car. Very comfortable in my opinion, as someone who is prone to seasickness from excessive rolling and high acceleration over long vertical distances going up and down that’s slightly out of sync with the waves due to mass.

I like the instant and smaller distance movements a lightweight cat provides.

[Mystic38]

thats a pretty close assessment imo, the ride for me is similar to a performance oriented monohull.. bit sharper, quicker and less forgiving.. but, you do have the option to slow down, or crack off by 10-15 degrees to ease the motion if uncomfortable.. regardless the result is still something that is far less physically tiring than a monohull imo.. but different.

Originally Posted by rslifkin

No real cat experience to draw from, but I'd expect the ride to be a bit more like a planing hull powerboat. Not necessarily more motion, but faster, sharper motion (especially at higher boat speeds), and a bit more of the bobbing like a cork feeling. Depending on your preferences and what you're used to, you may or may not find it uncomfortable.

[Barra]

Nah dont agree thats true most of the time.

Downwind the rides on condo cats and performance cats are similar at least on the ones I have compared.

Upwind the lighter faster boat will fall off waves and crash around more on the same heading but what is missing is that the performance cat can bear off and gain a smoother ride with the same or better VMG as the condo cat bashing upwind.

Ive done it many times to clear a headland or whatever and usually the condo cat with the same target just ends up motor sailing after awhile which makes the ride even rougher.

In confused seas all cats suffer compared to monos regardless of heading and thats where the monos often have an edge.

[tomfl]

Just my two cents but after sailing on more boats than I can remember since my Dad first took me out in 1954 I have never seen a boat that that is not uncomfortable under some conditions; and most boats can be comfortable under other conditions.

No question cats do have an issue with bridge deck slamming; but the standard solution is to fall off a few degrees. Problem with that is in some conditions like confused seas this may not solve the problem. Another big issue for me is living in Florida I have been in the Gulf Stream with a North fetch in the wind (especially in 15kn plus) and the square waves this wind direction against the current produces is uncomfortable in almost any boat I have seen.

On the other hand as was noted earlier if the wind direction is for a broad reach in many boats a quick cat will have the apparent wind move far enough forward that you will be on a maybe a close reach. But my experience has been that by falling off you speed increases enough that your VMG is as good, and sometimes better, than sailing closer to the wind; not to mention a much more comfortable ride.

Bottom line is any of the boats in the vid could be very comfortable if the skipper wanted to alter the course for that reason; or in the alternative none of the boats would be comfortable under the Gulf Stream square wave conditions.

As an aside there have been multiple threads that discussed cat v monohull comfort on passages. The consensus seems to be cats are less taxing in part because they sail flat and as a rule are faster. Another big plus for cats is moving around on deck; especially going forward is usually much easier on a cat as there is a lot more deck space.

Most important thing I have learned over the years is that there are boats that seem to fit people. I am 5'8" so over six feet of headroom is a waste for me. On the other hand I am in the water almost every day when cruising so ease of entry and boarding on the sugar scoops is mandatory. While I get it that self tacking jibs cause a performance hit as a single hander they are a must. Without listing every thing I look for in a boat I would point out that my list is not the same as the guy in the vid so his boat would not fit me and vice versa.

Only way to know which boat is right for you is get on it and sail it.

[Boatfreak]

As someone else said all boats are uncomfortable in some sea states, however there is something about fast cats which I have never experienced on a mono because they are not fast enough. I trained as a Naval Architect (many years ago) and spent the first six years of my career analysing the performance of warships in waves. A vessel responds to approaching waves depending on their frequency of encounter and how this relates to the natural periods of the ships motion. The natural periods are functions of bouyancy and weight distribution. If for instance the wave frequency is close to that of the natural pitch frequency, extreme pitching will result. If it is far away from it the motion will be much gentler. What happens when a boat heads more quickly in to the waves is that the frequency at which they encounter the hull is increased. Thus if they were close to resonance when stationary they are getting further and further from it the faster they go and the motion becomes much smoother, a condition naval architects call " supercritical". I have experienced this on my previous catamaran in the relatively small waves in the Solent. Whether it is of any practical value depends on whether you have the nerve to try on larger waves at sea, and of course the longer the wave you start with the less likely it is to happen.

[Tupaia]

Originally Posted by Barra

In confused seas all cats suffer compared to monos regardless of heading and thats where the monos often have an edge.

Downwind +160 degrees mono's can and do suffer terrible rolling motion even in relatively calm conditions.

[nortonscove]

Such a subjective thing. I've worked on tugs quite a bit and the last tug we'd owned was incredibly heavy and deep. Hundred feet LOA and swinging a single ten foot prop. It's motion was what I'd call waddling. I hated it. There were few days of pounding but I personally didn't enjoy the ride. The father inlaw loved it.

[jmh2002]

What also should be considered in the general sense (and this applies to both monos and multis) is that extra length is almost always a positive aspect - except when paying marina bills and redoing the antifoul.

So the old adage of long waterline and weight towards the centre holds true for cruising boats too.

This messes with the simple lighter vs heavier scenario a bit but is useful to understand if you have the possibility (budget) to add length for the same volume/used volume.

So a bigger heavier boat actually ends up lighter, relatively, by percentage load.

You don't suffer from an ultralight uncomfortable boat, boat you are not heavy relative to waterline, load carrying, etc.

It's something to consider in this conversation too.

[Slainte1]

The boats described weren't fast cats, they may be fast roomerans. It depends on what is meant by performance. At high performance multi has to be sea kindly or it won't be as fast.
Dick Newick always said you can choose two out of the three :speed, room, low cost, but not all three. You make your choice

[jmh2002]

Originally Posted by Slainte1

At high performance multi has to be sea kindly or it won't be as fast.

I don't agree. Real high performance boats are not really "sea kindly", at least certainly not in the traditional sense. Look at a Volvo boat, or an IMOCA, or an Ultime Class - are they sea kindly?

No not really - they are on the ragged edge all the time and they thrash the crew to death.

And they are generally best when used towards their limit, ie: towards their max design potential.

But I wouldn't describe this as sea kindly - and I have personal experience on many high performance monos and multis (30kn+), and superfast motoryachts (50kn+) too.

As a cruising boat you will not normally be anywhere near this max design potential.

As I understand it "sea kindly" means a boat that will look after you, and be comfortable - a high performance boat can do that too, but it generally needs a lot more attention to do so.

[Roshni]

As stated a faster cat is faster, hence more noise. But due to better weight focus, particularly if carbon mast, then less pitching. So at 8 knots boat speed the performance cat should be more comfortable and need less wind to achieve it.