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  #381  
Old 05-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

I did not loose sail area (according to the second owner he shortened the foot by 3' and raised the tack by 18", foot is now 15' and luff a tad over 37'), it was merely relocated to forward of the mast. One of my new headsail configurations consists of a Genny (25'luff, 15'foot, clew a little high, head 12' from masthead) on the headstay and Yankee (35'luff on 5' pennant, clew 20' off the deck, head 1' from masthead) on the topmast stay...they set very nicely together. $100 for used sails+$140 for pair of used Barient 25 two speed winches+misc hardware and work making new winch mounts total cost about $250, not including new standing rigging 1/4" 316SS $250, new halyards 230' 7/16 Endura $140. If those costs don't seem to add up I got the wire through a commercial source and paid spool price of 75cents/ft and have a contact who sells New England Rope so can get "end of spool" pieces for about 60cents/ft also have a contact for SS hardware.
The original rig had a nasty weather helm...the only purpose behind it I can figure was you only had to own two sails, a really big main (which in anything but a light air was overpowering the boat anyway, probably why it had a triple reef)and a fractional self tending jib (which according to the owner that removed it "tracked very poorly"). The present rig which allows for a masthead jib and/or a cutter rig which more than makes up for the lost sail area. It will be quite a while before I can afford a new main so I will put alot of thought into what I get and be open to suggestions.
The original rig was not designed for performance, rather simplicity (not spreaders, no fixed backstay, no cap shrouds, fractional with no jumper struts, no winches) and to be single. handed. Atkin even said of it "This is not a racing machine". Second owner had a bit more sense about performance, while still keeping the boat easy to single hand.
I am a poor cursing sailor and am trying to do as much as I can with what I have.
Bob: I don't think my boat is perfect, just less imperfect than some people suggest.

Last edited by wolfenzee; 05-25-2013 at 04:22 PM.
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  #382  
Old 05-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

I did not think that your boat had necessarily lost sail area, when it when the boom was cut down and a second headsail added. But what did happen is that the center or the sail plan moved 3-4 feet forward of where it was designed. If the boat is balanced now, this suggests that Atkins got it wildly wrong in his original design. Going battenless, will require a hollow leech and that well decrease the sail area by roughly 45-60 square feet as compared to a sail with a reasonably normal amount of roach. It will also move the dynamic center of effort forward some more potentially damaging the balance that you currently have.

That was all that I was saying,
Jeff
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  #383  
Old 05-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by Jeff_H View Post
I did not think that your boat had necessarily lost sail area, when it when the boom was cut down and a second headsail added. But what did happen is that the center or the sail plan moved 3-4 feet forward of where it was designed. If the boat is balanced now, this suggests that Atkins got it wildly wrong in his original design. Going battenless, will require a hollow leech and that well decrease the sail area by roughly 45-60 square feet as compared to a sail with a reasonably normal amount of roach. It will also move the dynamic center of effort forward some more potentially damaging the balance that you currently have.

That was all that I was saying,
Jeff
The mainsail was changed in 1982, and the boat has been sailing happily with this sailplan for about 30 years. Though I might take into consideration different methods of sail manufacture I am not suggesting any major changes (the sail I have is battenless and I was simply looking as a direct replacement for what I have...with maybe a few tweeks) to the mainsail other than maybe paying closer attention to the camber of the mast.
The changes I have implemented will not impact the center of effort to a degree to have a negative effect. example: the Yankee has a 35' luff and is flown on a 40' stay w/a 5' pennant, the clue which is about 20' off the deck is several feet behind the mast, his helps to move the center of effort closer to the mast, but with the other headsail have enough effort before the mast to balance it out. If I should decide to just fly the Yankee, I can adjust it's center of effort with the pennant.

Last edited by wolfenzee; 05-25-2013 at 04:43 PM.
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  #384  
Old 05-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

In William Atkin's defense, I would like to point out that the Captain Cicero (originally the Kathrine S.) was a commission which the client decided not to have built. The name was changed to Captain Cicero and the plans were fist published in MotorBoating Magazine in 1945 as a "29'10" round bildged knockabout". That sailplan could have been from input from the client, I was told by a another source (which I am not entirely sure of) that the original rig was a gaffer with a bow sprit. The published sailplan and it's problems could have simply been from Atkin conceding to the requests of a client and/or an error in reconfiguration of a gaff rig. Though the published sail plan show main and working jib, there was an allowance for a jib topsail, this would have balanced things out a tad.

To any of you who have designed a boat and/or rig for a customer or had one designed for yourself, in most cases the customer has last say and it is up to the designer to convince the customer what will work and what wouldn't and why
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  #385  
Old 05-25-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

I started to write something but wifi crashed and I lost it...so lets go again.
Of the "formulas" out there for performance, some are totally useless and can at best be used for comparative purposed and/or guide lines....some on the other hand are quite accurate. I am addressing the formula on hull speed in displacement vessels based on LWL. Though it is relatively accurate, variables in hull design do strech this formula a bit. While some boats find it very difficult to get to "theoretical hullspeed" (if at all), other have no problem at all and push the limits.
My boat has a LWL of 25' giving it a HS of 6.75kt. Under power 6.5kt at 2000rpm is a comfortable speed while 7kt at 2200rpm is possible (but that's my limit) but extremely inefficient for only a 1/2kt gain. 6.5kt is easily obtainable under sail or power (96% of HS or 1.3*sqrt of LWL).
Would you say 6.75kt is my "theoretical HS" while 7kt is my "obtainable HS" ?
If HS is the limit my hull can go through the water...the easily obtainable and maintainable 6.5 must be my cruising speed or some such thing.
For my purposes worring about a 1/2kt or less just isn't worth trouble
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  #386  
Old 05-26-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

Wolfie, HS isn't a "limit" - it's a calculated value, related to LWL, and defined as the speed at which the wavelength of the boat's bow wave (in displacement mode) is equal to the boat length. That's all it is. There's nothing "theoretical" or "obtainable" about it. It doesn't take into account beam, hull shape, wave conditions, or anything else which might dictate the most "efficient" maximum speed through the water and was, IIRC, a means of categorizing racing yachts with wildly different LOD.

What you're referring to is something else entirely - usually referred to as "Boat Speed"... "BS" for short.
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Last edited by Classic30; 05-26-2013 at 08:15 PM.
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  #387  
Old 05-27-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

NIGHT RUNNER wins Swifsture Race overall,,,,again!

My-Tai the Flying Tiger 10m that I designed won the Juan de Fuca race overall.
That's two first overalls in the biggest race in the PNW.
Not bad for a kid from Ashfield.
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Last edited by bobperry; 05-27-2013 at 11:23 AM.
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  #388  
Old 05-27-2013
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Re: Bob Perry's take on Wolfenzee's dream boat

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Wolfie, HS isn't a "limit" - it's a calculated value, related to LWL, and defined as the speed at which the wavelength of the boat's bow wave (in displacement mode) is equal to the boat length. That's all it is. There's nothing "theoretical" or "obtainable" about it. It doesn't take into account beam, hull shape, wave conditions, or anything else which might dictate the and was, IIRC, a means of categorizing racing yachts with wildly different LOD.

What you're referring to is something else entirely - usually referred to as "Boat Speed"... "BS" for short.
Thank you for setting that straight, I am not racing against another boat, and the calculation based solely on LWL is about 1/4kt off what appears to be the "most "efficient" maximum speed through the water" (to reach 6.5kt isn't difficult, anything else will require a bit more experimentation).I have always known there were so many variables involved that such simplistic formula could be accurate, though it was accurate enough (until you start splitting hairs). For my purposes what is important is to know what my boat is capable of and how to attain that.
The age, condition and cut of my sails leave alot to be desired...but considering what I can do with what I have got, I am not complaining...though I do realize that new sails will improve on what I have dramatically. As it will be a long time before I can afford new sails I plan on sailing with what I've got and trying other combinations and/or variations of used sails until I decide what will suit me best......then I will have a new suit of sails made. For my purposes I need to balance ease of use with performance.
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Re: Bob Perry's take on Wolfenzee's dream boat

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JonB:
I am working hard right here on Port Susan trying to create my own alternative universe.

Hot rod Alberg 35:
I hate to kill a fairy tale but here goes.
If you removed the rudder from the A35 and moved it aft on a skeg you would probably be moving the rudder about 3' considering how long the chord of the A35 keel is as designed. The rudder would be tucked up under the counter so it would have to be a deep rudder. Now add a skeg and the net result will be a gain in wetted surface. So light air speed will suffer. The only possible benefit of moving the rudder would be to possibly improve helm feel, steering and most certainly handling under power. There is nothing about simply moving the rudder aft and adding a skeg that would improve the speed of an A35.
On my first boat, a "Pipe Dream 36, getting rid of the huge keel hung rudder, and replacing it with a much smaller, and far more effective rudder 6 ft further aft, on a skeg, was a net reduction in total wetted surface.
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Re: Bob Perry's take on Wolfenzee's dream boat

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Originally Posted by Jeff_H View Post
Wolf,

I don't know who told you that but its wrong on both counts. Battenless mainsails generally need way more leech tension to work and that greatly shortens the life of the sail. You see them leech flapping their way around the world slatting the sail cloth fibers to death.

In term of lost sail area, a hollow leech on a boat like yours will typically have foot of hollow. Working off Atkin's drawings, with an 18 foot boom, you should be able have roughly 1 foot to as much as 16" of roach. That is somewhere between 45 and 55 square feet of sail area that you are giving away. That is really huge.

When you consider all the facts, like fact you like that your boat is well balanced, that you already have a two foot shorter boom than Atkins drew, and Atkins shows roach on his mainsail, and that hollow leech cut mainsails count on a lot of hook in the leech to minimize flapping, a hollow leech cut sail sounds like a really bad idea.

Jeff
When I arrived in New Zealand on my first boat, from Rarotonga, my 12 year old mainsail had torn several times on the way down, due mostly to battens. In New Zealand I had the roach cut straight, eliminating the need for battens, and a full length tape sewed up the leech .I put another three thousand miles on that sail, in squally, strong trade winds, without poping a stitch. Now, when I get a new mainsail, the first thing I do is remove the roach and battens, which are responsible for over 80% of sail repairs, which is why sailmakers come up with so many flimsy excuses for roaches and battens. It is a source of much income in the repair buisiness for them.
When I asked friends arriving at Fanning island with full length battens, what they thought of them they said "Battens suck." After they had sailed to New Zealand and back to Canada , I asked them again, they said" Battens still suck."
Battens drastrically reduce the life expectancy of a cruising sail, and a good cruising boat should be designed to balance well without a roach on the main. Roaches and battens are a racing gimmick which should be left on racing boats. They have no place on a good offshore cruising boat.
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