Help with a Sailplan for a wooden classic / Francis Herreshoff Buzzards Bay 14

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  • 22 Feb 2017 20:51
    Reply # 4627022 on 4497913

    Hi David and Rob, 

    Yet another long gap in getting back to you as Pete and I are working flat out on battens, mast and sail plan so not much time for online 'chat'.

    No blame to anyone but a big credit is definitely due! 

    Turning up for AGM is touch and go as it stands now but we are giving it our best shot. 

    Ahoy



  • 17 Feb 2017 22:30
    Reply # 4615409 on 4497913

    Hi Linda,

    You always fancied an Aerojunk and now you are going to have one! Very pleased for you and delighted to hear that you have a expert right at hand. David Webb plans to get Little Gypsy Girl fitted with an Aerojunk rig for the AGM junket - will we see Francis sailing there as well?

    Rob


    Last modified: 17 Feb 2017 22:31 | Anonymous member
  • 15 Feb 2017 07:10
    Reply # 4609934 on 4497913

    Hi Linda,

    thanks for the credit, hopefully it will all work out well and not turn into blame!!

    When I looked at all of the plans, proposals etc it just seemed obvious to me that the Aerojunk met the criteria and would be achievable with the minimum of change and work in the existing boat. It would also be possible to use a shorter mast than the other proposals without loss of performance.

     I hope that it all works out well. David.

  • 15 Feb 2017 06:32
    Reply # 4609892 on 4497913

    Dear All 

    Apologies for silence. Francis went into the water and there was a lot of unnecessary nursing her! She is now on her mooring and we are back to work.

    Thanks so much for your comments. It appears that the leads are very small. For keeping the mast in its original position it seems obvious to use a well balanced sail.

    Had it not been for David Webb's advice I probably would have not consider it - and Pete did not suggest it outright. But I really like aero junk especially because I sailed it for 800 miles and was very impressed by it. Also it will fit very well within all the constraints. 

    I made up my mind and went for the aero junk. Would love to hear your comments, since it has not been east to come to a decision. 

    Thanks again for all the effort put into discussing and designing the best possible option. It has been a very interesting and valuable experience.   

    The battens are in a process of being made, all the material has been ordered and Pete is hard at work! ...Francis's Final Rig

    Keep you updated with the progress. 

    Ecstatic Linda !

  • 12 Feb 2017 10:52
    Reply # 4605129 on 4497913
    Anonymous member (Administrator)

    I buy Ted Brewer’s points, but would like to add a couple more:

    A small transom, indicating fine lines aft:
    This lets one heel the boat over without getting increased weather helm. The Buzzard Bay 14 appears to be such a
    well-balanced hull, just as my 29’ Johanna was.

    (With her full bow and fine stern, Johanna could easily be sailed to windward with 30° heel, and little rudder input)

    The other factor is size:
    On a small boat like this, the rudder is relatively huge, and even if the keel is ‘long’, it is still not very long, so the rudder is not buried in a very thick boundary layer. Just imagine when looking at that boat‘s profile, that it was a 40-footer: The rudder would then look abnormally big. If this little 17-footer needed 3 or 6° rudder input, I bet most would say that it was well balanced. Try to hold a 40-footer’s rudder at those angles, and it would soon feel tiring.

    Cheers, Arne

    PS: Paul J Thompsonn fixed the weather helm problem on his La Chica by fitting a new, better rudder further aft. Has he written an analysis anywhere about that, apart from reporting big improvements?


  • 12 Feb 2017 08:48
    Reply # 4605064 on 4497913

    In Ted Brewer Explains Sailboat Design, he gives this list of factors shortening lead:

    • Short keel
    • Deep draft
    • Narrow beam
    • Stable hull
    • Fine forward waterlines
    • Low aspect rig
    • Two-masted rig
    Possibly the two that apply here are narrow beam and fine forward waterlines, but these are offset by some of the other factors. I think I still incline towards putting the mast step in the original position, raking the mast forwards as far as is practicable, and using a sail planform that can tolerate an adjustable balance area. 
  • 12 Feb 2017 01:30
    Reply # 4604854 on 4497913

    I have now found the picture of the Buzzards Bay 14 sailplan. Interestingly this shows the CLR and CE of the original sail plan. The lead is just under 7% (not taking the rudder into account)! Apparently the boat was beautifully balance with the original rig, so it it tempting to stick with Francis Herreshoff's thumb suck. Any thoughts on why this boat should have such a small lead. 

    original Herreshoff sail plan

  • 12 Feb 2017 00:28
    Reply # 4604804 on 4497913

    Hello David, 

    Nice to hear from you and thanks very much for your valuable input. I like the idea of aero junk. Pete is scratching his head, remeasuring plans, boat etc and we don't know what is next ... Watch this space! 

    Hope your aero junk is coming together. Look forward to seeing us both on the water for AGM. 

    Linda

  • 10 Feb 2017 10:36
    Reply # 4602287 on 4497913

    Hi All,

    looking at the design of Francis and the photos of the hull I tend to agree with Arne that the lead should be in the order of 16 to 17 percent. I found with Arcadian that 12% lead created a lot of weather helm and she did not balance until I had added to the keel aft to bring the lead back to that of the original Bermudan rig which was 17%. If the existing mast step and deck reinforcement are used then with the rigs proposed so far she will, in my opinion, have excessive weather helm. I would like to suggest an Aero junk rig similar to Pete's on Oryx. This would have approximately 25% of the sail forward of the mast, would have somewhat longer battens and would require a shorter mast rigged close to vertical. This would reduce the amount of work required and would provide a very efficient rig for the boat.

    All the best with your new boat Linda.

  • 10 Feb 2017 10:15
    Reply # 4602279 on 4601864
    Anonymous member (Administrator)
    Pete Hill wrote:
      I have designed several rigs that balanced well using the PJR formula, but apparently you (and Arne) are using a different way to work out the CLR and lead, which gives different results.

    Pete,

    I think that getting the lead right is much easier if the boat has a fin keel or centre-board than if the boat has a long keel. When I take the trouble to find the CLR of the underbody (by balancing it on a ruler), I mostly do it first with the rudder on, and then I cut off the rudder to find the CLR without the rudder. On a long-keeled boat I use the CLR with rudder cut off, and I generally aim for 14 -16% lead. The under-cut keel profile of the IF had me reducing it. Frankly, I got sloppy and just plonked the rig on this time. The resulting weather helm was a bit on the high side, so I shifted the sail forward (see drawing below). In hindsight, the first lead was only 11% and now it is 13%. My guess is that I could have increased the lead to 15% on Ingeborg before having lee helm.
    I will keep it as it is, now.

    The keel profile of Linda's  Herreshoff is not unlike that of my IF, so I would not have less lead than 14% (not counting rudder).
    But I could be wrong, of course...

    Cheers, Arne

    PS: Was the last BR in use on Linda's boat a partial or masthead rig?



    Last modified: 10 Feb 2017 10:51 | Anonymous member (Administrator)
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