Light air performance of different multihulls?

[fxykty]

Originally Posted by arsenelupiga

i was really impressed by lagoon 52 greatcircle in last arc. Close to 60 ft outremer was 20 % faster than Lagoon 52. Outremer had their own person on board so they sailed to the max. Greatcircle also sailed to full potential. See their videosl aggon and outremer, to get ideas of speed, effort, etc.



The winner - french quick cat also sailed to the max was another 20% faster. But they were basically empty outdoing that english 80 ft cat of some billionaire.



Result seem quite realistic. Lagoons design has proven really good and sacrifices one accepts for speed - less space, less carrying capacity, more price, do not appear justified to me.

Enough of using the ARC to prove anything. It is a relatively short, mostly downwind, generally light-moderate conditions ‘race’ in which some boats are prepared for racing and sailed hard, others are prepared for cruising and just mosey along, and any boat at any time can motor. The very fact that fat and heavy accommodation-oriented boats compare favourably with skinnier and lighter performance-oriented boat for boat speed and distance sailed shows that the event is ridiculous for evaluating actual performance.

[NaClyDog]

Originally Posted by arsenelupiga

i was really impressed by lagoon 52 greatcircle in last arc. Close to 60 ft outremer was 20 % faster than Lagoon 52. Outremer had their own person on board so they sailed to the max. Greatcircle also sailed to full potential. See their videosl aggon and outremer, to get ideas of speed, effort, etc.

The winner - french quick cat also sailed to the max was another 20% faster. But they were basically empty outdoing that english 80 ft cat of some billionaire.

Result seem quite realistic. Lagoons design has proven really good and sacrifices one accepts for speed - less space, less carrying capacity, more price, do not appear justified to me.

How do you know exactly how those vessels were sailed? Just based on their times?

[wingssail]

Originally Posted by fxykty

Running the brace/guy from the windward bow projects the windward tack at most half the beam to windward of the centreline and our from behind the mainsail. Given that the foot is likely 1.5 x beam you are only projecting about a third of the spinnaker out of the lee of the main. That works in moderate conditions as you have more than enough power, but in light winds the spinnaker will collapse behind the main.

I have seen cats with long spinnaker poles exactly for this reason - to project the spinnaker well out from behind the main. Simpler solution seems to me to be dropping the main.

You are right that a gennaker has less area and less luff projection than a spinnaker and also less than a top down asymmetric, but it also has less area behind the main and may perform better than a symmetric together with a main, except in light-moderate airs where the spinnaker will generate more power.

Apparently wing spinnakers fly better in light airs so maybe they wouldn’t suffer as much behind a main?

So three options for deep downwind, in order of cost least to most:
1) symmetric spinnaker, with a sock
2) top down asymmetric, on a furler
3) wing (symmetric?) spinnaker, with a sock

1) and 3) could be used with a pole to project the sail further to windward; 2) does this on its own.

fxykty, Pardon me for interjecting a monohull sailor's opinion.

First, in light air if you can't keep the spinnaker filled a better solution than dropping the main is to reach up a little. We find that reaching to the optimal TWA gives us better speed towards the destination. I am sure this works for multihulls also. Of course you will have to jibe somewhere down the line, but it is far faster towards your destination than going dead downwind with no main. Many racers have a little cheat sheet taped to the deck near the helm position which tells us what TWA is fastest for each wind speed.

Next, it is not a given that an asymmetrical spinnaker has less area than a symmetrical spinnaker. A sailmaker can make the asymmetrical any square footage you want. My A2 asymmetrical is 95% of a full size symmetrical and it could have been made bigger. Sailmakers make cruising assyms small so they are easier for the cruising sailor. If you can handle a 100% sized symmetrical kite you can handle a 100% sized assym.

Socks: many folks will disagree with me on this, but I'll say it anyway. Socks don't really make spinnaker handling any easier. There are a few extra lines to deal with, which can get tangled especially if you have jibed since you hoisted, and each evolution, hoisting or dowsing, takes two steps instead of one. If you are double handing then one person on the foredeck (or tramp) can easily pull down a spinnaker if the other person can control the halyard and steer (or touch buttons on the autopilot). Of course if your halyard is at the mast, then that makes it a touch more difficult. Hoisting is fast and easy without a sock. Just ask dockhead. He didn't get his sock before he went on the first race after getting his spinnaker and he found it was easy without it. Judy and I have only once tried a sock and found it not worth the trouble. We took it off and made a laundry bag out of it.

[fxykty]

Originally Posted by wingssail

fxykty, Pardon me for interjecting a monohull sailor's opinion.



First, in light air if you can't keep the spinnaker filled a better solution than dropping the main is to reach up a little. We find that reaching to the optimal TWA gives us better speed towards the destination. I am sure this works for multihulls also. Of course you will have to jibe somewhere down the line, but it is far faster towards your destination than going dead downwind with no main. Many racers have a little cheat sheet taped to the deck near the helm position which tells us what TWA is fastest for each wind speed.



Next, it is not a given that an asymmetrical spinnaker has less area than a symmetrical spinnaker. A sailmaker can make the asymmetrical any square footage you want. My A2 asymmetrical is 95% of a full size symmetrical and it could have been made bigger. Sailmakers make cruising assyms small so they are easier for the cruising sailor. If you can handle a 100% sized symmetrical kite you can handle a 100% sized assym.



Socks: many folks will disagree with me on this, but I'll say it anyway. Socks don't really make spinnaker handling any easier. There are a few extra lines to deal with, which can get tangled especially if you have jibed since you hoisted, and each evolution, hoisting or dowsing, takes two steps instead of one. If you are double handing then one person on the foredeck (or tramp) can easily pull down a spinnaker if the other person can control the halyard and steer (or touch buttons on the autopilot). Of course if your halyard is at the mast, then that makes it a touch more difficult. Hoisting is fast and easy without a sock. Just ask dockhead. He didn't get his sock before he went on the first race after getting his spinnaker and he found it was easy without it. Judy and I have only once tried a sock and found it not worth the trouble. We took it off and made a laundry bag out of it.

You’re absolutely correct regarding heading up rather than dropping the main for best performance (and it’s what we do on our boat), but I understood the OP is asking about relaxed cruising and not about active sailing. On a catamaran the big roach main is a real PITA to reef or take down during a squall when heading broad reach or downwind, so when cruising in squally conditions it’s easier to leave the main down.

Absolutely correct about the sizes of sails - it’s why I suggested an asymmetric as one of options. A gennaker is a smaller bottom up asymmetric, but that’s a code sail or screecher, not an asymmetric spinnaker that’s usually furled top down to allow for the extra area up high.

I don’t agree with your dismissal of socks for cruisers. Most racers are comfortable handling spinnakers without socks, but not for cruisers, especially if they don’t have high speed electric winches for their halyards. A sock means you can take your time hoisting the spinnaker without worrying about it filling when half up. Heck, when racers use elastics (not anymore!) or wool to bind the spinnaker into a sausage, that’s effectively a sock.

For take downs, it means you don’t have to worry about the spinnaker filling when half down. You don’t have to worry about heading dead downwind and blanketing the sail behind the main, you don’t have to carefully play the halyard to avoid the sail dropping into the water, you don’t have to have someone grabbing the sail and wondering whether the next billowing will lift them up off the foredeck. Why have all the stress?

It is likely different on a monohull where you don’t have much of a foredeck, but in a cat there’s no issue about space or managing the sock line.

[Factor]

[QUOTE=arsenelupiga;3220932]

you compare apple to peaches. Boats you mentioned are coastal cruisers, and the other group is ocean cruisers.

Not so. Seawind 1160 have circumnavigated. And all the other designs have as well. Poor old Loch Crowther would roll over in his grave if he heard you call his boats unfit for oceans. And with respect I reckon I have probably done more sea-miles in blue water than most.

These have extra carrying capacity. It is like going into desert fro 3 months or 2 weeks. You need carrying capacity to be able to stay away for that long. Some people like ocean cruisers simply because they are so comfortable that can replace their house/appartment.

the going in the desert analogy is probably a good one, When I go bush I have a small light Camper Trailer and carry what I need not everything I own. Means I can use a lighter more economical vehicle. I see others with Land Yachts being pulled by v8 landcruisers and Dodge rams etc. More expensive more gear more weight more extra fuel to carry, harder to handle.

You think that is bad for some reason. Some other people actually plan long distance sailing

Yep I plan, I just dont carry everything I own, and I am interested in enjoying the sailing.

[Factor]

As an aside

Originally Posted by fxykty

Heck, when racers use elastics (not anymore!) or wool to bind the spinnaker into a sausage, that’s effectively a sock..

Its an offence in most Australian jurisdictions to deposit garbage overboard and elastics and wools and zip ties etc etc are all garbage within the meaning of the MARPOL convention. Not surprisingly Australian Sailing doesn't want to talk about this.

[JustMurph]

As someone new to using a spinnaker, I'm loving the sock on mine on my 48' Cat. It's easy as, low stress and doesn't take long at all. But I'm no racer. I like to sail fast, but I'm definitely a cruiser.

[wingssail]

Originally Posted by fxykty

You’re absolutely correct regarding heading up rather than dropping the main for best performance (and it’s what we do on our boat), but I understood the OP is asking about relaxed cruising and not about active sailing. On a catamaran the big roach main is a real PITA to reef or take down during a squall when heading broad reach or downwind, so when cruising in squally conditions it’s easier to leave the main down.

Absolutely correct about the sizes of sails - it’s why I suggested an asymmetric as one of options. A gennaker is a smaller bottom up asymmetric, but that’s a code sail or screecher, not an asymmetric spinnaker that’s usually furled top down to allow for the extra area up high.

I don’t agree with your dismissal of socks for cruisers. Most racers are comfortable handling spinnakers without socks, but not for cruisers, especially if they don’t have high speed electric winches for their halyards. A sock means you can take your time hoisting the spinnaker without worrying about it filling when half up. Heck, when racers use elastics (not anymore!) or wool to bind the spinnaker into a sausage, that’s effectively a sock.

For take downs, it means you don’t have to worry about the spinnaker filling when half down. You don’t have to worry about heading dead downwind and blanketing the sail behind the main, you don’t have to carefully play the halyard to avoid the sail dropping into the water, you don’t have to have someone grabbing the sail and wondering whether the next billowing will lift them up off the foredeck. Why have all the stress?

It is likely different on a monohull where you don’t have much of a foredeck, but in a cat there’s no issue about space or managing the sock line.

OK, I agree

[wingssail]

[QUOTE=Factor;3221028]

Originally Posted by arsenelupiga

Not so. Seawind 1160 have circumnavigated. And all the other designs have as well. Poor old Loch Crowther would roll over in his grave if he heard you call his boats unfit for oceans. And with respect I reckon I have probably done more sea-miles in blue water than most.

the going in the desert analogy is probably a good one, When I go bush I have a small light Camper Trailer and carry what I need not everything I own. Means I can use a lighter more economical vehicle. I see others with Land Yachts being pulled by v8 landcruisers and Dodge rams etc. More expensive more gear more weight more extra fuel to carry, harder to handle. Yep I plan, I just dont carry everything I own, and I am interested in enjoying the sailing.

Factor, we all do what we have the resources to do. If you don't carry everything with you it means you have somewhere else to put it, maybe a house somewhere or a friend or relative somewhere. But if you have truly cast off your shore bound ties then you must carry everything. Of course that is not for everyone. So the boat you choose must fit your lifestyle. I'm not advocating one over another, but we sold everything and moved aboard. What we own is with us. Our vessel must carry it.

Then there is the self sufficiency issue. If every port you visit is close to a West Marine, Budget Marine, or Whitworths, then you can go light. Any problem you can deal with until you are in port is easily solved. But if you venture further afield you need to be able to fix your critical systems without help from the shoreside marine services.

The bottom line here is that for some the capability to carry 2000-4000lbs is important. For others, just carry enough to get you to the next town. If you have the right boat you can do both: be self sufficient and still enjoy great sailing.

[mikedefieslife]

Originally Posted by wingssail

fxykty, Pardon me for interjecting a monohull sailor's opinion.

First, in light air if you can't keep the spinnaker filled a better solution than dropping the main is to reach up a little. We find that reaching to the optimal TWA gives us better speed towards the destination. I am sure this works for multihulls also. Of course you will have to jibe somewhere down the line, but it is far faster towards your destination than going dead downwind with no main. Many racers have a little cheat sheet taped to the deck near the helm position which tells us what TWA is fastest for each wind speed.

Next, it is not a given that an asymmetrical spinnaker has less area than a symmetrical spinnaker. A sailmaker can make the asymmetrical any square footage you want. My A2 asymmetrical is 95% of a full size symmetrical and it could have been made bigger. Sailmakers make cruising assyms small so they are easier for the cruising sailor. If you can handle a 100% sized symmetrical kite you can handle a 100% sized assym.

Socks: many folks will disagree with me on this, but I'll say it anyway. Socks don't really make spinnaker handling any easier. There are a few extra lines to deal with, which can get tangled especially if you have jibed since you hoisted, and each evolution, hoisting or dowsing, takes two steps instead of one. If you are double handing then one person on the foredeck (or tramp) can easily pull down a spinnaker if the other person can control the halyard and steer (or touch buttons on the autopilot). Of course if your halyard is at the mast, then that makes it a touch more difficult. Hoisting is fast and easy without a sock. Just ask dockhead. He didn't get his sock before he went on the first race after getting his spinnaker and he found it was easy without it. Judy and I have only once tried a sock and found it not worth the trouble. We took it off and made a laundry bag out of it.

Hmmm, does that even work though. In very light winds, you would a have to go so far off course that the extra speed probably wouldn't make up anything over he extra distance.

Into light wind, the apparent wind come further and further forward very quickly with only slight increases in speed. I've had so that I've have to bear off more and more, so much so that the tacking angles become absurd and are essentially going backwards.

Isn't it also widely accepted that on a cruising cat, DDW is typically faster, or at least usually not slower for reaching the destination, broad-reaching and gibing? I've seen it mentioned a few times both on these boards and possibly article by Shuttleworth IIRC.

[wingssail]

Originally Posted by mikedefieslife

Hmmm, does that even work though. In very light winds, you would a have to go so far off course that the extra speed probably wouldn't make up anything over he extra distance.

Into light wind, the apparent wind come further and further forward very quickly with only slight increases in speed. I've had so that I've have to bear off more and more, so much so that the tacking angles become absurd and are essentially going backwards.

Isn't it also widely accepted that on a cruising cat, DDW is typically faster, or at least usually not slower for reaching the destination, broad-reaching and gibing? I've seen it mentioned a few times both on these boards and possibly article by Shuttleworth IIRC.

mikedefineslife, It really does improve your downwind VMG to reach up. You can look at the polars diagram I've attached, for a Seawind 1600 catamaran. In all wind strengths this boat, typical of cats, has the best VMG at about 140deg TWA. So if you head up to that TWA angle you will bring the wind forward and the sails will fill easier, and you will be faster to the destination. Additionally it will feel faster and be more fun, just don't get carried away and sail too high. That also is slow.

If you head dead downwind you will have trouble keeping the sails filled. If you drop your mainsail, yes, the breeze will keep the kite filled, but you will be slow.

[fxykty]

Originally Posted by wingssail

mikedefineslife, It really does improve your downwind VMG to reach up. You can look at the polars diagram I've attached, for a Seawind 1600 catamaran. In all wind strengths this boat, typical of cats, has the best VMG at about 140deg TWA. So if you head up to that TWA angle you will bring the wind forward and the sails will fill easier, and you will be faster to the destination. Additionally it will feel faster and be more fun, just don't get carried away and sail too high. That also is slow.



If you head dead downwind you will have trouble keeping the sails filled. If you drop your mainsail, yes, the breeze will keep the kite filled, but you will be slow.

At 40 degrees off course (assuming the destination is DDW) over lets say 2000 nm to go is a heck of a lot of extra distance to sail. Especially if it takes you away from intermediate waypoints or an expected weather change. There can be reasons to need to go further downwind than optimum VMG.

Your monohull has inline spreaders and a small roach mainsail. Don’t underestimate the problem of having to douse a large roach mainsail with full battens downwind or even reaching during a squall. That is why many cat cruisers will douse their main for downwind destinations.

But if you don’t mind the extra off-course distance it is amazing, especially in lighter winds, how far forward apparent wind can go even with 140 degrees TWA or so. If you’re feeling playful then head up a bit too far, gain speed, then slowly bear away while maintaining that speed. Eventually you slow down, so head up again to build speed: basically follow an S course that averages the optimum downwind angle. Of course, this doesn’t work for an autopilot, so the value of this technique for ocean crossings may be low.

[barnakiel]

This one is a nice benchmark for light airs cruising mono performance. But she is a bit to short to pitch against cruising cats as they are bigger.


https://www.hallberg-rassy.com/filea...s/HR372VPP.jpg


barnakiel

[Dave_S]

Originally Posted by wingssail

mikedefineslife, It really does improve your downwind VMG to reach up. You can look at the polars diagram I've attached, for a Seawind 1600 catamaran. In all wind strengths this boat, typical of cats, has the best VMG at about 140deg TWA. So if you head up to that TWA angle you will bring the wind forward and the sails will fill easier, and you will be faster to the destination. Additionally it will feel faster and be more fun, just don't get carried away and sail too high. That also is slow.

If you head dead downwind you will have trouble keeping the sails filled. If you drop your mainsail, yes, the breeze will keep the kite filled, but you will be slow.

Interesting thread.

Looking at the polars of a number of boats not just this one, I can see that it looks like it would work. However, I have watched boats try to gain ground by doing this and I have never seen it work. We are not allowed spinnakers so that should make the job of the chasing boat easier. It always works out to be faster DDW wing on wing. These are performance cruising boats not race boats.

[jmh2002]

It definitely works, that's why the racers do it.
And I have both seen it work as well as done it myself many times.

But, there IS certainly a crossover, boat, sail configuration, and conditions (and mark, waypoint, or destination) dependant, where running DDW (or at least sailing a lower angle) is faster overall because of the shorter distance sailed.

The polars of course indicate that but they don't account for all the variables, and often neither do the crew, so the boat may be being sailed sub-optimally.

An example is that some 'sport' boats with only fixed bowsprits can suffer in a mixed fleet race because of the big angles they need to sail in certain conditions.

Another monohull example is flying an assymetric, but from a lowered conventional spinnaker pole, instead of a fixed bowsprit, to be able to square the pole back and sail deeper with the same sail (as well as being better able to adjust for different sails).

So keeping or adding the option to sail lower or higher as required is useful both from a performance point of view, as well as comfort, convenience, safety, wear and tear, etc (note the points the @fxykty mentioned earlier).

And it's relatively easier to achieve both possibilities on a multihull, so that's a great positive benefit.