Catamaran tacking angles , really that bad???

[Tupaia]

[QUOTE=Bullshooter;3144748]

Originally Posted by Tupaia

A conventional large mainsail forward or a small mainsail further aft both have the effect of moving the CE aft that benefits pointing. Call it a by product if you like.

Wait, I was following along pretty good but this statement has me confused. How can these two opposites have the same effect?

Please explain. Possibly I need more coffee...

They are not really opposites. When you compare the CE (Centre of Effort) of a big roached mainsail on a conventionally set mast with that of a high aspect mainsail on a mast set further back they are similar. The tendency will be to weather cock into the wind. Both will sail to windward quite well under mainsail only.


The benefit of the small mainsail set aft is the ability to fly a bigger headsail moves the CE forward, better for downwind. A big mainsail with a small headsail is much less suited to down wind as the CE does not move forward by that much, hence the reason a genaker or code zero on a prodder is used.


There are of course masses of other variables involved, keel, dagger board shape and position, rudders etc so this is very general and is a long way off topic.

[barnakiel]

To get better pointing, I would bet on daggerboards way above any CE movements.


You want narrow deep foils below water as above. Minimum drag, maximun drive for best upwind efficiency, inluding the angle.


No so much different from what is going on in an efficient mono-hull.


b.

[Tupaia]

Originally Posted by barnakiel

To get better pointing, I would bet on daggerboards way above any CE movements.


You want narrow deep foils below water as above. Minimum drag, maximun drive for best upwind efficiency, inluding the angle.


No so much different from what is going on in an efficient mono-hull.


b.

Totally agree, except that the monohull is limited because it is fat.
Sp = 1.4 Root (WLL)
Multihulls are not limited by this but must be able to sail closer to the apparent wind if they are to benefit from the increased speed.


Tacking angles are not an indication of windward performance.

[barnakiel]

Yes. I understand this. At the end of the day no matter what angles sailed the first one at the top mark (or at the bar) wins.


vmg, vmg ... ;-)

b.

[Captain Bill]

Originally Posted by barnakiel

To get better pointing, I would bet on daggerboards way above any CE movements.


You want narrow deep foils below water as above. Minimum drag, maximun drive for best upwind efficiency, inluding the angle.


No so much different from what is going on in an efficient mono-hull.


b.

Oddly enough I don't find this to always be the case. Lst year I was sailing south of Nassau on my way to Hghiborne cay in the Exumas. True wind was about 60 degrees off the bow and about 10 to 12 knots. A Catana came out of one of the marinas and started heading towards Highborne as well along a suggested Explorer chart route about .6 nm behind us according to the AIS. We both had up full sails which in this case was me with my little camberspar jib and them with a genoa witch I'm guessing was at least 130%. Certainly a lot more sail area than I had. I remarked to the admiral that we would probably be looking at their stern in a short while. In the binocs it didn't look like they had the boards down all the way but neither were they up all the way either. Probably a wise precaution as that route is a bit shallow, at least in the first half. Much to my surprise instead of them passing us we steadily opened the gap on them. By the time we got to Highborne we had opened up the gap to 4.7nm. It may just have been that a Catana is more sensitive to weight than my Endeavourcat as we were both loaded down for cruising, but I was never the less surprised at arriving at Highborne a good 45 minutes or so ahead of the Catana.

[arsenelupiga]

my measured upwind VMG average settling around 3.2kn. This is open sea long distance cruising loaded, around 3T of stuff. We have done 3 m waves upwind, that was the toughest one. Although larger waves seem to be easier to sail than chop.

We do touch 5 kn VMG when good conditions. Not ideal but does the job well enough.

[wingssail]

Originally Posted by Tupaia

A typical ORMA 60 going to windward in 25 knots of wind will be doing 18-20 knots the TWA will be 45-47 degrees (90-94 degree tacks) but the AWA will be 27-28 degrees and AWS about 40 knots.

An IMOCA 60 in the same conditions will be doing about 10-11 knots at a TWA of 47 degrees AWA 34 d and AWS 33 knts. If you pointed up to say 30 d TWA you would be making only about 5 knots and would need to pull the AWA down to under 25 degrees...

I'd have to say that the IMOCA would do better at 40 TWA. They would be doing 10 knots and better than 7.5 VMG. The AWA would be around 34d, very doable and very comfortable. 80d tacks.

The ORMA would still be faster, 12.6 knots at TWA of 48, and VMG of 8.5.

These are racing boats. Cruising boats don't make these numbers, but my monohull boat is close, 6.75 knots, TWA 40, VMG 5.75, on the wind vane, double handed, and we have our house with us.

[Tupaia]

Originally Posted by wingssail

I'd have to say that the IMOCA would do better at 40 TWA. They would be doing 10 knots and better than 7.5 VMG. The AWA would be around 34d, very doable and very comfortable. 80d tacks.

Actually no. The AWA would need to be sub 29d the polar limits the speed at 40d TWA to 9 knots regardless of wind speed. The sweet spot is 18 knots TWS. VMG would be about 6.9 knots.

Originally Posted by wingssail

The ORMA would still be faster, 12.6 knots at TWA of 48, and VMG of 8.5.

These are racing boats. Cruising boats don't make these numbers, but my monohull boat is close, 6.75 knots, TWA 40, VMG 5.75, on the wind vane, double handed, and we have our house with us.

These figures are meaningless without a reference wind speed, but a boat speed of 6.75 @ TWA of 40 will give a VMG of just over 5 (5.17knots) this is just trigonometry.

[wingssail]

Originally Posted by Tupaia

These figures are meaningless without a reference wind speed, but a boat speed of 6.75 @ TWA of 40 will give a VMG of just over 5 (5.17knots) this is just trigonometry.

The wind speed used for this model would be the one originally proposed, 25 knots. I think in the run I used previously had 26 knots, or maybe another parameter was used (I didn't save the run).

I don't really want to argue with you over these differences.

The point being made is not whether an ORMA multi can match an IMOCA to windward (it can) or which of those two would have the tightest tacking angles. This is irrelevant to the OP's question, and regardless of how he phrased it, he wants to know if he's going to have bad tacking angles and slow progress to windward on a cruising catamaran, compared to a monohull.

It of course all depends on the actual design of both vessels. But in general a typical condomaran will have poorer windward performance (worse tacking angles) than a typical modern monohull cruiser. On some other points of sail they will shine, but not all.

What is important to remember is that few people considering an ex-charter catamaran (or even a new cruising catamaran) are really going to be persuaded to buy a Gun Boat so that they can get great windward performance. The prices of these exotic multis are orders of magnitude over the boats we see out cruising. They might buy a stock Jeanneau monohull which would do so at a fraction of the price.

No, the buyer of the cruising catamaran should just focus on the advantages of the boat he is considering and when he wants to beat to windward in a narrow channel, forget about it and turn on the motor. If he wants sparking sailing performance on al points of sail he'll get a great monohull. If he wants to blast around on a broad reach, heck, just get a jet ski. If he wants max square footage and a great view, he'll go for the condo.

[Tupaia]

Originally Posted by Tupaia

These figures are meaningless without a reference wind speed, but a boat speed of 6.75 @ TWA of 40 will give a VMG of just over 5 (5.17knots) this is just trigonometry.

Originally Posted by wingssail

The wind speed used for this model would be the one originally proposed, 25 knots. I think in the run I used previously had 26 knots, or maybe another parameter was used (I didn't save the run).

Originally Posted by arsenelupiga

my measured upwind VMG average settling around 3.2kn. This is open sea long distance cruising loaded, around 3T of stuff. We have done 3 m waves upwind, that was the toughest one. Although larger waves seem to be easier to sail than chop.

We do touch 5 kn VMG when good conditions. Not ideal but does the job well enough.

So your 43ft mono has slightly better windward performance (max 5.17 knots VMG) when compared to arsenalupiga L400 (max 5 knots VMG).

So that does answer the question.

I have to disagree with you regards performance comments in general. You have a "custom" IOR racing monohull at the top end of the performance scale. Most production cats are charter oriented with the emphasis on safety and offer pretty average performance. A "custom" cat from a recognized designer, Woods, Hughes, Kelsall, Schonning, Newton, Shuttleworth, White, Crowther, Oram will have really startling performance to windward and will not be anywhere near the price point of a Gunboat.

[wingssail]

Originally Posted by Tupaia

I have to disagree with you regards performance comments in general. You have a "custom" IOR racing monohull at the top end of the performance scale. Most production cats are charter oriented with the emphasis on safety and offer pretty average performance. A "custom" cat from a recognized designer, Woods, Hughes, Kelsall, Schonning, Newton, Shuttleworth, White, Crowther, Oram will have really startling performance to windward and will not be anywhere near the price point of a Gunboat.

Oh please, Tupaia. Our boat is 40 years old, and while it was a successful IOR boat in it's time (the whole genera was not thought to be particularly fast) and it is loaded with liveaboard and cruising stuff, and sailing, while cruising, with smallish dacron sails. Hardly the top end of the performance scale. Yet we can match the numbers I've given you.

Most modern monohulls are much better performers than we are as the ratings for them reveal. A modern Beneteau or Jenneau or Hanse, or almost any other will have much better numbers than our old IOR war horse, as much as I love it.

If the OP or any other potential cruiser in the market for a boat for cruising can find a suitable cat from any of the designers you listed, with a layout and capacity for liveaboard cruising, for a comparable price, and is looking for a cat, perhaps he would be smart to buy it. What we see, and saw during our circumnavigation, are run of the mill cats which do not provide startling performance, of course along with a lot of run of the mill monohulls which would not either, but could if well sailed.

[barnakiel]

I do not agree with that Schionning sentence above.


I sailed one. It was a brick.


I have sailed a handful of designs and the Catana and Outremer always fared best. And recent Lagoons seem to be also pretty good (two of my clients have the most recent Lagoons, hence this insight). Not stellar, but way above the earlier boats from the same company.



I bet there are some brands above the two (I remember last time there was something called maybe TS in the ARC fleet) but since I have not sailed these, I will not guess how good they are. I can only guess from their results they are good.



b.

[Tupaia]

Originally Posted by wingssail

If the OP or any other potential cruiser in the market for a boat for cruising can find a suitable cat from any of the designers you listed, with a layout and capacity for liveaboard cruising, for a comparable price, and is looking for a cat, perhaps he would be smart to buy it. What we see, and saw during our circumnavigation, are run of the mill cats which do not provide startling performance, of course along with a lot of run of the mill monohulls which would not either, but could if well sailed.

Yes, now we agree. The majority of boats mono and catamaran on circumnavigations or just out there cruising are "run of the mill" performers. That would suggest that performance is not that important if the boat does what the owner want's it to do. I personally admire anyone who gets out on the water in whatever.

The primary issue here is really cost, "a layout and capacity for liveaboard cruising, for a comparable price", a catamaran costs more than a monohull, proas are cheaper... lets not go there.

Taken in by boat show marketing propaganda many potential purchasers of catamarans try to justify their choices by citing the performance benefits, which there definitely "can be", usually enjoyed by cats that are hardly marketed at all, "see listed designers". Then they chose a boat that is designed for a big specifically different "non performance" purpose, "charter". It will have a conservative sail plan, luxurious teak decks, wood trim and is as aerodynamic as a shed. They load it up with an American fridge, air conditioning, a generator big enough to supply a small housing estate, add a tender powerful enough to tow food and fruit and then ask about tacking angles.

[smj]

Originally Posted by barnakiel

I do not agree with that Schionning sentence above.


I sailed one. It was a brick.


I have sailed a handful of designs and the Catana and Outremer always fared best. And recent Lagoons seem to be also pretty good (two of my clients have the most recent Lagoons, hence this insight). Not stellar, but way above the earlier boats from the same company.



I bet there are some brands above the two (I remember last time there was something called maybe TS in the ARC fleet) but since I have not sailed these, I will not guess how good they are. I can only guess from their results they are good.



b.

Catana’s and Outremers are production built boats, Schionning is a designer not a builder. I’m guessing most Schionning designs are custom built so it may be the build that was the problem and not the design. The Wildcat 35 and Jaguar 36 are both Schionning designs but built way to heavy so probably sail nowhere near their designed performance.

[wingssail]

Originally Posted by Tupaia

Yes, now we agree. The majority of boats mono and catamaran on circumnavigations or just out there cruising are "run of the mill" performers. That would suggest that performance is not that important if the boat does what the owner want's it to do. I personally admire anyone who gets out on the water in whatever.

The primary issue here is really cost, "a layout and capacity for liveaboard cruising, for a comparable price", a catamaran costs more than a monohull, proas are cheaper... lets not go there.

Taken in by boat show marketing propaganda many potential purchasers of catamarans try to justify their choices by citing the performance benefits, which there definitely "can be", usually enjoyed by cats that are hardly marketed at all, "see listed designers". Then they chose a boat that is designed for a big specifically different "non performance" purpose, "charter". It will have a conservative sail plan, luxurious teak decks, wood trim and is as aerodynamic as a shed. They load it up with an American fridge, air conditioning, a generator big enough to supply a small housing estate, add a tender powerful enough to tow food and fruit and then ask about tacking angles.

Yes, we agree. The only thing you left out was the incongruousness of asking about tacking angles when, in all probability, they won't be doing any tacking.

PS, I've watched proas sailing, native ones and Russell Brown's. Can't say that many cruisers could be that attentive.