On 06/10/2018 09:11 AM, realink@iprimus.com.au [harryproa] wrote:

 

> This idea is just at the "napkin drawing" & mental exercise stage, but the idea is to eliminate the issues with soft wing sails

Soft wing wing sails are the future, and together with hard wings have been discussed here extensively.

Especially given the speeds boats of this ilk can achieve, where single panel sails begin to suffer in performance against the conformity of a wing. With the added benefit that the efficiency of the wing sail is such that area can be much reduced.

     I'm from the aviation community.   I've flown ordinary rigid wing aircraft, and aircraft with both single and double surface fabric wings, and even the old "lawn dart" Rogallo wing hang gliders.   There is no question in my mind that three dimensional airfoil sails would provide the best LD.... that is rigid wings.   I believe there are a number of reasons why the soft wing sail will not sweep the sailing community in spite of this.  It definitely will not become the norm in the long distance voyaging community, but may take off somewhat among a narrow sector racers and weekenders, and some of those who are early adopters of the latest and greatest.   Below are three photos of Pete Hill's Oryx with the three rigs he used on it in order.   On the first rig the sail laid against battens on one tack, and hung free on the other.... You can see the near side sail hanging free, and the far side against the battens.  Apparently dissatisfied with the performance of this rig, he picked the sails apart and made them in to soft wing sails..... second photo.  Ultimately he abandoned the soft wing sails for the Aerojunk rig in the third photo, which is still on Oryx as far as I know.   As you can see, his masts are rather short.  They are in tabernacles so that they can "easily" be laid down.  Unfortunately Pete doesn't blog about this stuff, so we can only guess, but I would assume that he assumed that the wing sails would be far more efficient than the other rig, and either discovered it was not as efficient as he had hoped, or found that they were a pain to handle, and not worth the gain.  You can clearly see that there is the classic "wishbone" around the mast, and separate tail section that is presumably hinged.

     I would assume that as Pete is a serious voyager, he found that on the normal trade wind routes, sailing downwind they offered no benefit, only offering some benefit when reaching and close hauled, but not enough to justify the headaches of dealing with the sail.   I haven't combed the JRA website to see if there is anything written there about this.

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