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Old 10-12-2017, 23:20   #661
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Re: Atlantic 57 Catamaran Capsized

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Originally Posted by admiralslater View Post
The idea that you can hold a course above a broad reach without boards is in my opinion preposterous. I have raced dagger board cats for since the early 80s ,and am very familiar with what happens with different board configurations . I understand that the discussion is cruising oriented but the principals are the same .
Dagger board cats need the board s to be used that is why they are there,the hull shapes are often different to take advantage the lift that a board produces .
On my PDQ36 the hulls are exceptionally slippery and if I raised the board on a close reach as suggested I would have leeway in excess of 10 degrees which is unacceptable when planning a passage . In a earlier post some suggested pulling the boards at night while going up wind . You actually night maintain a better position if you just took all the sails down and drifted.
There is no right answer for which and how boards should be used for instance our pdq is designed to use one board (leeward) infact we tack the boards when we are racing . We carry full board to weather even after the first reef if the sea stat allows . On reaches the amount of board varies based on the conditions ,at about 120 degrees I will raise them fully but not always
On our Outremer I not been able to get the info yet on if I am to run two full boards yet .
The boat is relatively new to us so I am being circumspect in the use of the boards and do use the weather board more when going up wind ,this is only for sea state again
A great deal of my racing on cats was on the same course as monhulls and we raced them head to head , leeway was always something we could compare both on and off the wind ,this is where I formed my opinions on board use .
Sorry for the drift
Have you ever actually tried? To say sailing upwind without boards would be worse than drifting is frankly, the most idiotic thing I've ever read on this forum! And that's quite an accomplishment!

FYI, I crewed on a boat that sailed about 300 miles to windward in 20-30 kt winds. With no daggerboards. The single board was broken. Leeway was worse than normal, but the fact is the boat made good progress. To try to say leeway would be greater than 45 degrees...... just amazingly ridiculous.
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Old 11-12-2017, 08:24   #662
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Re: Atlantic 57 Catamaran Capsized

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Have you ever actually tried? To say sailing upwind without boards would be worse than drifting is frankly, the most idiotic thing I've ever read on this forum! And that's quite an accomplishment!

FYI, I crewed on a boat that sailed about 300 miles to windward in 20-30 kt winds. With no daggerboards. The single board was broken. Leeway was worse than normal, but the fact is the boat made good progress. To try to say leeway would be greater than 45 degrees...... just amazingly ridiculous.
Well thanks, being number one is something a strive for . I will admit to a bit of hyperbole in my last post ,but I thought the comment about hauling boards at night was a bit much .
Now back on topic (what ever that is now) I would be interested to know what kind of boat you where on . 300 hundred to weather without out a board that most of been a slog. I also will do an experiment meet this summer and report back.
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Old 11-12-2017, 10:02   #663
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Re: Atlantic 57 Catamaran Capsized

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Is your boat a Danson generation 45? If so, the rules are likely the same as for our 55. The owner’s manual, that I translated into English very painstakingly and with help from Grand Large Services, clearly states that full boards, which on our boat are 60 cm below deck level, should only be used below 15 knots AWS. Above that, bring the windward up to deck level (75% deployed) and get rid of the leeward board completely as it doesn’t add any more reduction in leeway. By mid-first reef the manual recommends 50% board. The Outremer hulls don’t have a lot of rocker, plus you have the skegs. I’m not too sure about the 45 hull shape, YMMV, but for the 50/55 no boards are OK for anything other than upwind.

Regarding skidding the boat by raising the boards, this is about pointing higher (reaching or downwind, NOT beating) in lighter winds for higher apparent wind and allowing the extra leeway keep you on your intended heading. I certainly didn’t mean that you can’t keep your course due to skidding. But on our 55 we can beam reach (TWA) with no boards and maintain our heading with almost no leeway, as long as we’re going fast.

Below 8 knots boat speed without boards our leeway increases quickly and we skid. If the resulting COG is good, then we’re going faster than if we pointed straight at our COG with boards down to limit leeway. In lighter air only.

Unlike your PDQ, the Outremer definitely prefers the windward board alone in heavier air.
Thanks for that ,it does actually mirror pretty closely what I do . I do have a question on the use of the weather board over the lee. I understand using the weather board in rough conditions as a way of releasing turning moment if the hull should come up .
I struggle with the concept of it being more efficient than using the lee board as technically the weather board is more prone to cavitation. Having just watched the start of the Volvo I’d did not see anyone using the weather board only.
Back to what I said earlier as a seamanship issue I agree.
The 45 has a very similar shape to its big brothers and the hulls are quite narrow and deep compared to other designs which would line up with your comments about not needing boards at speed and explain why it feels like it is on rails . It does not tack as well as I would like but it was not designed to be an around the buoys racer.
Just saw that a 2002 55light just won the ARC ! One of three boats that did not motor and the only cat that didn’t. Danson knew his stuff
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Old 11-12-2017, 10:16   #664
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Re: Atlantic 57 Catamaran Capsized

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Frankly, I think the daggerboards have eased the drift considerably. [SIC]

This thread started with questions surrounding the capsize of a performance cat, Such a cat had daggerboards, of course.

I have learned much here from members fxykty and admiralslater on the subject. Thank you both!

For instance...
I was quite surprised to hear that the PDQ likes to have just a leeward board in some conditions. This contradicts my intuition, as the tripping concern would have me spooked. I'm missing something. Now I want to learn more...
Cyan ,the reason that we use the lee board is that it is deeper in the water and therefore does not cavitate as much . The boards where designed so that one provides all the lift needed while going to weather. It has to be pretty lumpy before I start changing the configuration which I do to reduce load on the boards ,not because I am worried about going over . Not often but we have flown a hull and quite often sail on the sweet spot with the weather hull just kissing .
When we are cruising I but both boards down halfway and leave them .
As for “tripping” there is nothing like a broad reach with full chute to get the blood warmed up
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Old 11-12-2017, 10:57   #665
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Re: Atlantic 57 Catamaran Capsized

I've sailed 4 different cats with daggerboards; Catana 47, Outremer 51, Catana 58 and Aikane 56. All of them behave differently under similar conditions. Shape of the hulls, skeg or not, the rudder size and placement, the shape and size of daggerboards make a huge differences. The only thing in common is that after a certain speed (8-9 kts) you hardly need boards.
You learn by trial and error on every boat..


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Old 11-12-2017, 11:25   #666
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Re: Atlantic 57 Catamaran Capsized

Hey Admiral, there is a difference between performance sailing and cruising. For performance sailing, fly the windward hull and use the leeward board. Racing is about efficiency first and not safety. But remember that your reserve of righting moment is a heap less when you’re flying a hull as that is the peak of the righting moment curve.

When cruising, the windward hull always stays immersed, other than partial lifts due to wave action. There should be no cavitation of the windward board except possibly on the odd wave. Our hull is it’s maximum 0.80 m deep at that point and I’ve never dared to power the boat up enough to even come close to 50% lift.

For cruising, you want to reduce the loads on the rig and avoid any major loading. Think about how close to the working load limit you’re taking your standing rigging when you fly a hull, then plow through a wave. It takes a lot of load to lift a hull right out of the water.
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Old 11-12-2017, 12:05   #667
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Re: Atlantic 57 Catamaran Capsized

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Originally Posted by admiralslater View Post
Cyan ,the reason that we use the lee board is that it is deeper in the water and therefore does not cavitate as much . The boards where designed so that one provides all the lift needed while going to weather. It has to be pretty lumpy before I start changing the configuration which I do to reduce load on the boards ,not because I am worried about going over . Not often but we have flown a hull and quite often sail on the sweet spot with the weather hull just kissing .
When we are cruising I but both boards down halfway and leave them .
As for “tripping” there is nothing like a broad reach with full chute to get the blood warmed up
Thanks for the details!
I did lurk in the "Daggerboard Catamarans" thread on CF earlier this year, but it got a little weird half way through. (after lots of good info)

Using just a weather board would seem to have an obvious natural safety valve, where just a leeward board would be the opposite. (though I didn't consider cavitation before.)

If the designer of the PDQ recommends only a leeward board, could it be that he is just a bit of a daredevil?

Most opinions that I find are of this type from a MQ article:
in talking with Peter Johnstone over the years, however, I’ve come to the conclusion that during heavy weather, it is better to have the weather board down and the leeward board up. If you are close or broad reaching in strong conditions and an approaching wave breaks against the weather hull, it would be better to slide sideways down that wave with no leeward board in the water to “trip” the cat. If the weather hull comes out of the water—an unlikely event on most cruising catamarans—the weather daggerboard also becomes less exposed to the water, allowing for more leeway and less likelihood of “tripping” on the board.
Daggerboards | Multihulls Quarterly

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Old 11-12-2017, 12:55   #668
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Re: Atlantic 57 Catamaran Capsized

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Hey Admiral, there is a difference between performance sailing and cruising. For performance sailing, fly the windward hull and use the leeward board. Racing is about efficiency first and not safety. But remember that your reserve of righting moment is a heap less when you’re flying a hull as that is the peak of the righting moment curve.

When cruising, the windward hull always stays immersed, other than partial lifts due to wave action. There should be no cavitation of the windward board except possibly on the odd wave. Our hull is it’s maximum 0.80 m deep at that point and I’ve never dared to power the boat up enough to even come close to 50% lift.

For cruising, you want to reduce the loads on the rig and avoid any major loading. Think about how close to the working load limit you’re taking your standing rigging when you fly a hull, then plow through a wave. It takes a lot of load to lift a hull right out of the water.
I agree with entirely and even though i have seen the video on YouTube of a guy sailing a Outremer with the weather hull dancing I would not do it .
I do it while racing my 36 but I am fully crewed .

My goal was help withe the understanding of boards and how they operate . Getting boards and the complications that they entail and not using them to the best of their abilities is a bit of a waste
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Old 12-12-2017, 02:04   #669
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Re: Atlantic 57 Catamaran Capsized

Telling people a daggerboard boat couldn't hold a course above a broad reach without boards down is hardly helpful. And a long way from the truth.

We're talking about cruising sailors avoiding capsize at night in squally conditions. We're not talking about getting the very best performance from the boat. You can do that in the daytime.
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Old 12-12-2017, 02:36   #670
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Re: Atlantic 57 Catamaran Capsized

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Drifting is as drifting does. Unless the mods think there’s value in creating a new thread.
No because the drifting hasn't finished yet, you haven't discussed suitable anchors for a drifting catamaran.

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Old 12-12-2017, 05:04   #671
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Re: Atlantic 57 Catamaran Capsized

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No because the drifting hasn't finished yet, you haven't discussed suitable anchors for a drifting catamaran.

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Oh boy! Anchors!

And, I bet that cat drifts worse than a mono too!

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Old 12-12-2017, 08:52   #672
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Re: Atlantic 57 Catamaran Capsized

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Telling people a daggerboard boat couldn't hold a course above a broad reach without boards down is hardly helpful. And a long way from the truth.

We're talking about cruising sailors avoiding capsize at night in squally conditions. We're not talking about getting the very best performance from the boat. You can do that in the daytime.
Perhaps I should have said some board . However I believe we may have exhausted this subject .
Now anchours that's something we can get into
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