Minimum TWA for cats

[3cdad]

I've been actively sailing cats for about a year - took all four ASA courses, and then bareboat chartered various cats for family trips (FP 36', FP Saba, Lagoon 450F). Just returned from a week in the BVI on a Lagoon.

I'm in the research stage of a potential cat purchase in the next year or two, and one thing that I have been unable to find is a detailed comparative analysis of how various cats perform upwind - ie., how close they can point. I know that this is not their preferred point of sail, and that cats spend most of their life on beam/broad reaches or runs.

The Lagoon 450F we were just on could only get about 45 degrees AWA, but this translated into a 65-70 degree TWA, which is the more informative measurement when one it trying to make progress upwind. I just saw a FB post from a Helia 44 owner saying that he's only able to point about 54 degrees AWA/83 degrees TWA before his sails complain.

Daggerboards and less windage/freeboard are marketed as solutions to this problem but, again, I don't see much quantitative analysis of actual performance upwind.

Is there little interest in this issue simply because few owners sail close to the wind anyway, choosing to just motor instead when it's necessary?

Any sources available that have done a comparative analysis of upwind cat performance?

[tomfl]

Maybe a little OT but ….

I sailed a lot of one design when I was a kid. All the boats were as identical as possible but it was obvious that some were pointing higher than others. I have seen lots of folks claim that when he was driving the AC boats Dennis Conner was able to point higher than anyone else.

Not claiming some boats don't point higher than others, just pointing out that some folks can sail higher than others.

The conventional wisdom is that when cruising on a cat (probably any boat for that matter) pointing as high as possible does not always result in the best VMG. Cats often can eliminate slamming (even if you have a high bridge deck) by falling off a little.

To get back on topic one problem with comparative analysis is that the wind and sea state would have to be the same to compare boats; something that is a tall order. On the other hand boats like Outremer, Catana, HH Catamarans, Gunboat and Tag Yachts to name but a few will definitely point higher than condomarans like the ones you seem to mention in your OP.

[3cdad]

But if your destination is directly upwind, and your TWA is already 70-80 degrees from that direction, if you bear off to gain speed then you will be approaching 90 degrees TWA, which means that you won't be making any progress to your destination.

[44'cruisingcat]

Upwind we sail at around 30' apparent. I say around, because in lighter wind it'll be 32', in strong wind it might be 28'.

The difference between AWA and TWA is the result of boatspeed. So while we might "only manage" around 50' true at 30' apparent, we could in fact sail higher by slowing down. This would have a negative effect on our VMG however.

Upwind, we've encountered very few cruising mono's (or cat's) that can stay with us.

[catsketcher]

My cat does much the same as 44C's. Upwind in tradewind conditions we usually do about 7-8 knots in 20 knots of wind at about 50 degrees true. In flat lake water we can push that up to 45 but sea state increases tacking angle.

Personally I could not cruise a boat that could not sail as well to windward as ours. (It has daggerboards and no flybridge or extra windage). On the East coast of Australia, it can be very helpful to be able to sail hard on the wind swiftly. Many times we have sailed on a long port tack and had a lovely day whereas most other cruising boats motor more slowly and have a harder time of it slowly motoring into the wind. My wife actually prefers windward sailing sometimes because the motion can be quite nice behind the reef. The ability to plan daysails of up to 80 miles hard on the wind is a great attribute for any boat I want to sail.

[3cdad]

44'cruisingcat... What cat do you sail?

[44'cruisingcat]

Originally Posted by 3cdad

44'cruisingcat... What cat do you sail?

Not a production boat, it's an Oram 44C, self built.

[Soma]

On a Gunboat we can sail up to about 27-28 AWA. Best polar performance is somewhere between 29-32 AWA. That translates to about 44-48 TWA. Add in 2-3 degrees of leeway and it's hard to achieve 90 degree tacking angle. In light to medium you'll tack through about 100 degrees (max). Angles close up as wind speed increases. Boat speed is 11-14, maxing out at about while 15 hull flying upwind.

On my F40 we sail a little faster and lower. 14-16 for boat speed and 105 degree tacking angle.

On an ORMA I've sailed about 16-18 upwind, tacking angles are about 105-110.

In my experience, no mini keel boat can sail upwind faster than they can motor (VMG).

[a64pilot]

I’m going out on a limb and thinking the OP was discussing the Lagoon / Leopard type of Cats, although it’s interesting to hear how well the performance boats can do.

[mikedefieslife]

Here’s an example of an old mini keel cat with low windage. Upwind AWA of 60 will result in best speed, about 7knts in 20knts of wind. TWA is more like 80 sometimes 90. In a recent sail going into 30knts of true wind my crew was shocked to find that tacking was actually resulting in us going backwards.

[3cdad]

That's what I've experienced with the charter type production cats. Tacking angles approach 180 degrees in stronger winds - ie., very little headway if your target is directly upwind. I like the comfort and space that those cats offer but, in the end, I want a sailboat that is not limited to TWAs > 80 degrees. I'm hoping something like the Seawind 1260, with less windage, freeboard, and narrower hulls will be able to sail closer to the wind.

[Dave_S]

Originally Posted by 3cdad

That's what I've experienced with the charter type production cats. Tacking angles approach 180 degrees in stronger winds - ie., very little headway if your target is directly upwind. I like the comfort and space that those cats offer but, in the end, I want a sailboat that is not limited to TWAs > 80 degrees. I'm hoping something like the Seawind 1260, with less windage, freeboard, and narrower hulls will be able to sail closer to the wind.

I'm crew on a Seawind 1260 for "not very serious" weekly racing, it sails well and surprises a lot of people. We manage to sail around 33-34deg AWA and tack around 120 degrees at better than half TWS.

My boat is a Schionning 1480 and sails much like the boats mentioned above around 2/3rds to 3/4 TWS around 30-40deg AWA and anywhere from 48 to 55 TWA dependant on conditions. Beyond about 28deg AWA it falls in a big hole.

I prefer to sail upwind, it feels like sailing, down wind feels like falling with style, with no air flow over your sails your just parachuting down wind.

[django37]

There are minikeels and minikeels, Some are deeper and better than others. And most condomarans have very inferior sails - and also fixed propellers. A lot can be done. This is from my Lagoon 380, carbon mainsail 7 sq m bigger than standard, folding props. sea is calm, wind is 6 m/s or 11 knots

[Sand crab]

44CC and Dave S, do your boats have keels?
And Django, how did you get more sail area? Also could you tell us the price on that carbon sail?



I sure would like to see some stats from the daggerboard cats like Outremer and Catana. And Maine Cat, too.

[django37]

Originally Posted by Sand crab

And Django, how did you get more sail area? Also could you tell us the price on that carbon sail?

Squaretop and more roach. Have sailed with it round the world now. Yes it was expensive, now 5 years old, so the price would be different now.