Catamaran tacking angles , really that bad???

[ixnax]

Originally Posted by fxykty

Not necessarily true. AFAIK, WS is part of a couple and both chose their boat. Same for the Cates. Same for the Dashews. Et cetera. Another anecdote, my wife and I both chose our performance oriented boat as we both prefer to sail well. There are many more couples like this.

Whatever boat you chose is right for you. Don’t push the reason for your decision onto your partner.

Interesting thread. Responding to no one in particular, and being a Cat sailor, I've noticed that the quality of the sails you have are a huge factor in all areas.

[smj]

Originally Posted by arsenelupiga

i found so far 2 types of sailor boats - singles and couples. Singles say what you say, couples are more concerned with comfort as there is social aspect of living on boat present.



If i was alone, would also look for more performance/ruggidity. But as a couple our choice is ideal.

All the people we know on performance cats are couples.

[tomfl]

Originally Posted by smj

All the people we know on performance cats are couples.

Except Charles.

[smj]

Originally Posted by tomfl

Except Charles.

He used to be a couple!

[tomfl]

Originally Posted by fxykty

Snip

For those of us with ‘traditional’ large main/small foretriangle set ups, we can only extend forward with bow poles. These come with their own problems, not the least being increased LOA. Sigh.

Well I have a bow sprit that folds 90 degrees and attaches to the forward cross member. LOA goes from 42 to 36 feet in a couple of minutes. Really helps save money when I check into a marina. I have to say I was concerned when I first got the boat but have been very happy with it as time passed. Love to fly my big screecher from the bow sprit.

[arsenelupiga]

Originally Posted by smj

All the people we know on performance cats are couples.

It is my observation from anchorages, rallies etc. that for live on boards comfort is more important than when using boat as a camper. OF course exceptions always exist and confirm the rule.

Normally is wife that decides the minimum level of comfort required to make a move. And if that means 100 L hot water per day then that is what is required.

[mglonnro]

Originally Posted by arsenelupiga

Normally is wife that decides the minimum level of comfort required to make a move. And if that means 100 L hot water per day then that is what is required.

And comfort also includes attitude, acceleration, etc of the vessel at sea and anchor. I'm pretty sure all of us on our boat would compromise with the hot water to get easier living and less seasickness.

[Tupaia]

Originally Posted by fxykty

This design concept is nothing to do with pointing ability and all about putting more sail area into easily furled sails that are relatively cheap - boom or mast furling are way too expensive at the charter/lower end of the cat market. A large mainsail is very important for pointing ability and that isn’t important for boats that are not design-optimised for upwind sailing. Makes a lot of sense for cruising cats and monohulls as well.

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.

Originally Posted by fxykty

This concept is being used with great effect in the single/short handed IMOCA 60s and the round the world trimarans - relatively small main used as the primary power control, and 3 or 4 furled jib and code sails permanently available up front for throttle control. Not optimised for close upwind (too much drag with all the furled sails), but very convenient for anything below that. They use structural furlers (no permanent forestay) for lighter weight and tighter furls.

To say that something like an ORMA 60 is not optimised for pointing is complete rubbish. It is a combination of CE, CLR and sheeting angles. Even when reaching the apparent wind is most definitely close hauled.

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. Off the wind at 130d TWA in 8knots of wind it would be doing 10 knots with the apparent wind still very much ahead of the beam at 52 degrees AWA.

Originally Posted by fxykty

Note that these furling headsails can only be used fully unfurled - no reefing - so having the correctly sized sails for their reefing charts ready to use is very convenient for single and short handed crews. The extra foredeck space also allows them to use multiple sails - the fully crewed Ocean Race boats often fly 2 or 3 J-sails simultaneously.

This is to even out the steps between 'gears' and keep average speeds as high as possible which someone has worked out to more advantageous than extra drag this imposes. They are still optimised for close hauled upwind, in fact they have fixed sheeting angles to eliminate the need for barbour haulers on the sheets.

Originally Posted by fxykty

For those of us with ‘traditional’ large main/small foretriangle set ups, we can only extend forward with bow poles. These come with their own problems, not the least being increased LOA. Sigh.

Collapsible prodder?

[Dockhead]

Originally Posted by wingssail

gsuescum, Looking at your instruments and reading your post it looks to me that you are doing very well! You are hitting 7.5 knots close reaching in 11.5 knots of wind. And I see that your apparent wind angle is around 40 degrees and I calculate that to be a true wind angle of about 65 degrees.

So, taking this back to the topic, what are the tacking angles of catamarans, I'd say your tacking angle is about 130 degrees and your VMG is under 4 knots knots. For going upwind, that is not particularly good. My VPP predicts that if you headed up 5-10 degrees you will get better VMG and tacking angles but you'll obviously be going quite a bit slower.

I don't know if your p495 has dagger boards, I'll bet not. I think that the modern cats with deep boards will perform better to windward. Your strength will be sparkling performance a bit off the wind.

No matter what boats we have, cracking off and going faster is very tempting and much more fun but it does not get us to a windward destination very fast.

Tacking angle without more is meaningless as a measure of upwind efficiency. I guess if I pinch up enough I can get to a tacking angle of 75 degrees. But no one would actually sail like that.


What's interesting is VMG directly to windward. Not all that easy to calculate, but it can be done. And you need to know this in order to know how to make best progress to windward. It may be closer to the wind, or further off, than you think.


When I rerigged my boat a few years ago with the specific aim of improving windward efficiency, I set a target of 5 knots in good conditions (flat seas, decent wind). I didn't make it, despite the carbon blade jib specifically designed by a pre-eminent Cowes Week sailmaker for upwind work. I can just touch 5 knots in ideal conditions, and normally I am happy for anything over 4.5. My tacking angle at best VMG to windward is never less than 100 degrees, and with a sea running may be more than that.


A deep bow to anyone able to do better than this in a non-racing boat.


As Wingsail hints -- apparent wind is not really your friend, when trying to get upwind. The faster you go, the further you end up off your course, if your destination is upwind. It's really hard, actually, to make miles directly to windward.



I learned some time ago that my chasing raw upwind ability was semi-futile. If you're cruising, you will get a lot better results out of TACTICS -- playing wind shifts, or in the worst case, choosing a different day to get somewhere which is upwind today. If you have good wind forecasts, this can pay off in spades over a multi-day passage. I'm still learning, but had great success with this on a passage from Iceland to the Faroe Islands two years ago. When we departed, Faroes were directly upwind. But a wind shift was forecast the next day. So we headed off almost S, instead of SE, caught the wind shift, and sailed right in.


I would not be put off by any theoretical loss of raw upwind ability of catamarans, if I wanted a cat. All cruising boats, even performance-oriented ones, pretty much suck upwind. If you need to get upwind, then if you're cruising, just use tactics to get there.

[jmh2002]

@Dockhead

I'm a bit surprised that your tacking angle at best VMG to windward is never less than 100 degrees, especially with the performance mods that you have made.

But do you have the shoal draft keel or the deep fin?

I guess the in-mast furling mainsail doesn't help either terms of direct windward performance.

[Dockhead]

Originally Posted by jmh2002

@Dockhead

I'm a bit surprised that your tacking angle at best VMG to windward is never less than 100 degrees, especially with the performance mods that you have made.

But do you have the shoal draft keel or the deep fin?

I guess the in-mast furling mainsail doesn't help either terms of direct windward performance.

Deep bulb, 7 1/2 foot draft.

I can easily do 90 degrees without pinching in good conditions (flatness of sea is most important). The blade sheets inside the shrounds and is designed to be efficient up to about 28 degrees AWA. But I usually get better VMG cracking off a bit and holding usually about 32-33 degrees AWA.

I don't have actual polars for my boat, but with say 15 knots of true wind, I can make hull speed (about 9.3 knots) from a slightly broad reach up to a pretty close reach, then falling off to about 7.5 knots of boat speed at max VMG to windward at say 32 AWA. That gives maybe 4.5 knots of VMG to windward.

If the sea is up at all, all bets are off.

I do quite well in tacking duels with race boats in the Solent -- kind of the local sport. I can always beat the J-Boats and Bene Firsts so long as the true wind is over 10-12 knots. I am typically cracked off a bit more but making better boat speed. I guess waterline length helps a lot in that, but still. The purpose-built upwind sail makes a big difference -- maybe 5 degrees better AWA than with the 120% yankee. Whether the furling mainsail is a big drag here or not, I can't really say. It trims very flat when necessary so little drag, but lack of roach of course means less power.

[jmh2002]

I guess the numbers are going in the right direction, but it does sound like the furling main is holding you back since it's the mainsail that provides the bulk of the lift upwind.

As you've mentioned in the past, furling is a trade off of ease of handling vs (upwind) performance.

[Cheechako]

Hard on to weather:
Hans Christian 38: Probably 130 degree tacking angle at best. Often worse. Heavy chop or headseas.. Forget it!
Passport 47: More like 100-110 degree tacking angle.
Lagoon 42 (deep keels for a cat): Maybe 140 degrees. But if you idle the leeward engine, you gain 15-20 degrees on each side! Crack off and use speed instead.

Had a good test with friends one day on the south side of Puerto Rico. 20 mile sail in a good 10-15 breeze. Their boat was a Perry designed 48 aluminum cutter. Ours was the Lagoon Cat. It was a close reach most of the day. We pretty much were on par speed wise for hours. They had a couple degrees of angle on us. When the wind went a bit further to the nose we were getting killed. Idled the leeward engine and were neck and neck again. They couldn't believe we arrived just behind them! I finally had to fess up about idling the engine on the side they couldn't see.:>)

[fxykty]

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.



To say that something like an ORMA 60 is not optimised for pointing is complete rubbish. It is a combination of CE, CLR and sheeting angles. Even when reaching the apparent wind is most definitely close hauled.

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. Off the wind at 130d TWA in 8knots of wind it would be doing 10 knots with the apparent wind still very much ahead of the beam at 52 degrees AWA.



This is to even out the steps between 'gears' and keep average speeds as high as possible which someone has worked out to more advantageous than extra drag this imposes. They are still optimised for close hauled upwind, in fact they have fixed sheeting angles to eliminate the need for barbour haulers on the sheets.



Collapsible prodder?

I wrote ‘optimised’, not ‘designed against’. The short handed cross ocean and round the world are not majority upwind courses, so the boats are not optimised for that point of sail. That does not mean they cannot sail insanely fast close hauled. They just aren’t going to windward as fast as if their designs were optimised for that (reference TP52, 18 foot skiffs, or even the America’s Cup foilers, all designed for windward/leeward courses). A small (relatively) main further aft with large headsails is not a rig optimised for VMG directly into the wind.

Regarding the bow pole, we do have a collapsible prodder. But not all boats do or can have an extending/swing-sideways/swing-up bow prodder. And once a bow pole goes beyond about a metre/3’ the handling of one or more tack locations is problematic and needs lots of control lines. That’s generally not cruising boat friendly.

[Bullshooter]

[QUOTE=Tupaia;3136934]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...