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post #1 of 7 Old 03-25-2002 Thread Starter
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Asym Spinaker-Sprit and RRS

Here ya'' go guys..Looking for some input on this one. I''m trying to get more performance out of an asym. This should get some real comments:

I think I figured out a way for a sprit for my asym spin. OK, it is permitted to pole out an asym spinnaker.

The normal method is from mast mounting to the clew. The asym normally has a tack line which runs through a turning block mounted forward of the forestay on the bow then it runs back and is secured to the cleat on the foredeck.In this configuration the tack of the asym is about 4 foot above the deck and only inches forward of the forestay.
My change, which I think would not violate any rules; is that I would take my whisker
pole and mount it on the normal mast fitting but let it drop down to the bow pulpit and secure it with a "fixed downhaul". Then mount the turning block in the forward jaw and lead the tack line through the turning block back to the foredeck cleat.

The advantage to this arrangement is that by extending the turning block 3-4 feet ahead of the boat is will let the asym to a better job of ''pulling'' the boat.
I looked through the rules and I think this might fly...
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post #2 of 7 Old 03-25-2002
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Asym Spinaker-Sprit and RRS

What kind of boat and are you racing PHRF, one-design, etc.?
What kind of Whisker pole? rigid or adjustable?
Anything that you can do to open the distance from the mast to the spinnaker tack will be of benefit - downwind.

However, there are some structural concerns that I offer: Is your pulpit going to take the strain ?.... probably not in most cases as they are usually not set to the deck with vertical loads (large backing plates and stress connections to bulkheads, etc.) in mind. Secondly, will the pole be strong enough as you will be essentially constraining the pole at midspan rather than from the ends - different stress considerations as whisker poles and spinnaker poles are designed for typically tension along the axis of the pole - not designed constraining or loading it from the middle.
For light winds ...... probably not a risk with anything you try.... but if the wind gets up and A-Kite starts to really lift the bow .... you can easily break/bend a constrained pole and possibly pull the pulpit free. For a boat with a strong waterline bow eye you might consider to attach a restraint from the eye to the outboard end of the pole etc. to take the strain instead of the pulpit.
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post #3 of 7 Old 03-26-2002 Thread Starter
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Asym Spinaker-Sprit and RRS

Aside from structural issues. Is it or could it be construed to be within the racing rules of sailing for a PHRF boat?
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post #4 of 7 Old 07-25-2002
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Asym Spinaker-Sprit and RRS

I believe that according to PHRF rules you arn''t allowed to tack the sail beyond your rated "J" dimension without a rating penalty. I have researched it a bit and have found out you can extend on a retrofit up to 25% of of "J" with a 3 second/mile penalty on the Chesapeake Bay at least. I am considering going to an asy spin for my O''Day 30 as its getting to be a real hassel to get a crew of 6 to go racing competatively.
Have you found any numbers on how much faster off the wind a boat is using a sprit vs tacking it at the stem of the bow?
Last weekend on our way home from the Solomons race we played around a bit tacking our downwind genoa to a whisker pole that was fastened to the deck and to the headstay fitting and extended about 4'' in front of bow. It seemed to be faster with app wind in the 90 to 120 deg range but did not actually get comparsion numbers.
I would be interested in any info you have found.
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post #5 of 7 Old 07-25-2002
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Asym Spinaker-Sprit and RRS

My sense from sailing on and against assymetrical spinackers is that unless you are sailing a very light weight easily driven boat that can really make big gains by sailing hot angles and scalloping down in gusts, your VMG will actually drop with an assymetrical spinacker vs a symetrical chute. So you are taking a 3 sec a mile hit for a sail that may be costing you more than than in downwind VMG.

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post #6 of 7 Old 07-30-2002
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Asym Spinaker-Sprit and RRS

My sailmaker has tried an interesting experiment on his Beneteau First 40.7.

He put a sprit on it, and races with an asymetrical. He does not use any symmetrical spinnkakers. The local PHRF ruled it a wash - the sprit & assym was cancelled out by the loss of VMG downwind. So he rates the same as my plain vanilla 40.7.

He''s won a few races so far but also lost some, it''s hard to tell exactly what the impact is still.

I expect to be racing against him next month, should be interesting. Eliminating the fact that he''s about 100x the sailor and driver I am, it should be interesting to see how the two boats compare.
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post #7 of 7 Old 01-03-2003
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Asym Spinaker-Sprit and RRS

We have an Evelyn 32-2 and is a light and pretty fast boat (PHRF 96). But our problem is that we always sail shorthanded (normally 4 and 2 over 60 years old). We have always sailed nonspinnaker have have been very successful in the fleet. So this year we want to go spinnaker and knew that if we did so, the decision would be to use use only an Akite. To facilitate this we have used a roller furling for our 155 and a snuffer for the Akite.

Whether we use a bowsprit in still being decided and we are testing out the cost of using a bowsprit over the permitted length. We think that the bowsprit is a necessity and plan on using the length that will give us the best advantage per penalty for length. Equally important is the your rules permitting the sprit to be articulated and by how many degrees. This would provide some fantastic speed improvement but you would have to make the sprit so it can be articulated on either side of course. We are also concerned as to the mounting of the sprit and I also agree that you should take a very, very conservative approach and anchor it the strongest way possible. The pulpit would be the last choice for us. Go for the waterline eye and make it strong as you can. The leverage that sprit will have that far out will mean some big pressures. If you err, built it too strong.

Good luck. Let me know how you do.
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