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Old 09-11-2016, 08:55   #1
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Boat: Bill O'Brien 1975 'Amazon' 8m x 4.5m Ketch-Cutter Cruising Cat & Wharram 'Melanesia' 5m Outrigger
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HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

Help … any ketch rigged (catamaran) sailors out there with more traditional headsails ie Yankee and Staysail? Your thoughts on yankee clew height and sail area etc much appreciated. (We are of an age where ease of sail handling matters - we don’t want a single large foresail to deal with!)

We have a choice of clew height for the new yankee - with a 65% sail (giving an appropriate scaled down area for our boat) the clew would be high to reach from the coachroof (about 2.3m/7ft) if need be without first lowering the sail. Larger yankees of 90% or 100% would be at more reasonable heights but there would be more sail to get between the the two forestays when going about and to be balanced by the fixed area mizzen sail.

We have never sailed in a boat with such a rig before but feel it would be good to be able to reach the clew more easily - what do you think? On the Bill O’Brien 30ft “Oceanic” catamaran (big sister to our 26ft “Amazon”) the yankee clew seems to be about a metre high but it did not have a roller reefing foil which went to the top of the mast.

When scaled down from the Oceanic to get the Amazon measurements, the yankee sail area would be 10.58 sq m ie nearer to that of the 65% sail (10.8 sq m) than the 90% or 100% sails.

It would be really good to get a second opinion, especially from anyone with Oceanic or Amazon sailing experience. Thanks for your input - photos below!

Bill O’Brien 8m “Amazon” Catamaran
https://www.facebook.com/groups/19959666274/
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Old 09-11-2016, 12:03   #2
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Re: HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

Not sure exactly what you're trying to achieve. But on a 30' boat, a clew that's 2m off of the deck is stupid high. To reach, in terms of lost sail area, & other things. Such as that if it's that high, you'll have trouble setting your jib cars far enough aft so that the sail will trim properly.

You can draw out how this will (or won't) work to scale on some graph paper, or with an architect's scale. So that you can see if the leads for such a sail will fit your boat.

A 10 sqm sail is pretty tiny, so much so that you can often trim them by hand. Why so small? That's like staysail sized on such a boat. Keep in mind that the true perk of a cutter comes into play when you're shifting down in terms of sail size, when the wind is increasing, or vice versa. So that by the time the jib is too big, or you've rolled it up as much as you can, then the staysail is enough to drive her on it's own.

Flying 2 headsails at once can actually add to the amount of work that you need to do. And on a lot of boats is aerodynamically worse on many points of sail, due to the air flow interference which is created. The only way to know of course, is to test it. But 9x out of 10, going with a single jib up front will yield you better results, & it's less work to handle.

Off of the wind, staysails can, again, can, assist your performance when used with a spinnaker. If their tack is located in the proper place on deck, & their height, & sheeting setup is optimized to work with the rest of the rig. And even racing boats such as in the Volvo Race spend a lot of $ in order to get this right.

What I'm saying, is to not blindly accept that a cutter rig setup is the optimal way to run things some or most of the time. Nor is it always the least work. Especially as you're juggling an extra sail. And also that the main is then operating in the bad air from 2 sails. Both of which are very close together, & thus making more than 2x the amount of disturbed wind for the main.

If you go to the website in the link OutRigMedia you'll find a lot of info on Jim Brown, & John Marples boats. Including the Searunner Construction Manual, & it has rig dimensions for all of the boats in it. Possibly to include sail dimensions for each, & all of the Searunners are cutters, including the 31', so it may help.

I found the sails themselves on my 31' Searunner to be undersized (for my taste), though she moved well in all but the lightest airs. And most of them will likely be similar to the ones on your boat. Though doing the 3 sail thing was a pain when solo.


Edit: Keep in mind that the cutter rig came about centuries before roller furling. In a time when sails could only be so large, both due to handling issues, & since sail cloth wasn't stong enough to allow for big sails. It's not an out moded rig, it's just wise to configure it to be used in a slightly different manner nowadays.
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Old 09-11-2016, 15:07   #3
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Re: HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

Just to clarify the situation, my wife and I are both in our 75th year and are committed to the ketch cutter rig for our old (1975) small 26ft/8m cat which will never be a fast into wind boat - it is in fact a motor sailer with twin inboard engines totalling 36hp and two props to slow us down when sailing!

Reefing will first be to get the roller reefed main away and continue with just the mizzen and headsails. Next the yankee will be roller reefed to leave the self tacking staysail and mizzen to drive the boat. The final option will be to reef the staysail and mizzen.

A lot of time will probably be spent with just the foresails and mizzen up day sailing (probably motor sailing when the wind is not in our favour)! Ours in not the sort of boat built for racing against the wind. It is very much a pocket cruiser which for much of the time will have a geriatric live aboard crew of two en route to a favourite island or other anchorage for a few days.

The standing rigging is already set up for the sail configuration. If we want the yankee clew lower down on the coachroof, the yankee will have to be larger than the designer originally specified, however, the combined area of the yankee and staysail should be well within the design limits.

Thanks for responding - all feedback will be very useful in deciding whether to go for a bigger yankee with a lower clew or stick to the designed size with a higher clew.

Bill O’Brien 8m “Amazon” Catamaran
https://www.facebook.com/groups/19959666274/
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Old 12-11-2016, 11:18   #4
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Re: HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

Have you considered a removable inner forestay, so that tacking any normal jib or genoa is easy, but if you expect (or get into) bad weather you can rig the inner , drop the genoa and carry on with a strong snug rig? If your headsail is a roller, it is even less work. Low clews give you very poor visibility and too high of a clew can mean you are almost standing on your tip toes to re-tie a sheet. You are not a racer so you can go with what is easy for you to work with. No big overlaps and no need for a sky high clew on jib or staysail. There are a few release levers available that are not as pricey as an ABI and only take a minute or 2 to set up. __Just something to think about. Good Luck ____Grant.
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Old 12-11-2016, 11:36   #5
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Re: HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

I just re-read your post and noticed that you have a self tending staysail. That more or less rules out a removable stay and makes tacking around the inner more difficult than if you had a conventionally sheeted staysail, where you let the staysail backwind just long enough for the jib to slide off of it. Having 4 working sails on a 26 foot boat does sort of complicate things. What size jib do you have on your furler now? You might want to consider having it cut down and try it before you have a brand new sail made., but again, too high of a clew is not needed. ___Grant.
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Old 12-11-2016, 12:03   #6
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HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

On my boat with a Yankee jib and a self tending staysail I find it easy to tack the Yankee around the inner stay when the staysail is set but difficult without the raised staysail. That's not a problem for me because I almost always sail with the staysail set. It fills in the space below the high foot of the Yankee and gives a nearly balanced rig without the yankee.

As has been mentioned above, with the high clew the angle of the sheet doesn't change as you roll in the Yankee so there is no need to move the jib sheet cars.
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Old 12-11-2016, 13:48   #7
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Smile Re: HEADSAIL CONFIGURATION - YANKEE CLEW HEIGHT

Thanks for all your responses - I have taken them into account and remembered that I had a local friend who has cruised his ketch cutter (monohull) for many years from the Baltic to the Med and around the North Sea including the British Isles.

Over the years, whilst cruising offshore, he found the most important aspects with respect to the choice of appropriate cutter headsails was visibility at sea and ease of tacking. Like mine, his boat was very much a motor sailer (14tons) whilst mine is a lighter catamaran (4tons) but I suspect we shall do the same sort of motor/sailing!

Armed with all that information, I have ordered a 13 sq m Yankee for the existing foil and all being well will follow that with 5.5 sq m Staysail (hopefully self tacking) to compliment the yankee when that is fitted. The main seems alright (it came with retro fitted mast roller reefing) and I bought a new Mizzen of about 5 sq m last year. The boat also came with a respectable Cruising Chute and Mizzen Staysail!

As far as possible, I have tried to restore the boat (1975) to the original rig (roller reefing excepted). Since the original design, a 26ft/8m 'Amazon' Catamaran pocket cruiser by Bill O'Brien came with a Foresail and Staysail, I scaled down the Yankee from her big sister his 30ft 'Oceanic' to get the new staysail measurements.

Yes, there are a lot of ropes and sails (4 standard ketch cutter sails plus Mizzen Staysail and a Cruising chute - doubt whether the latter two will get much use) to fiddle with which I hope numerous young grandchildren will enjoy playing with. However, when there are just the two of us, we shall reduce sail, probably to just the headsails and mizzen when motor sailing or in heavy weather to make life easier!

Again thanks to all for your input - if of interest, there are some photos on the link below:

Bill O'Brien Catamaran Designs
https://www.facebook.com/groups/19959666274/
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