Leisure 27 junk rig conversion

  • 17 Jan 2023 20:16
    Reply # 13061241 on 13055766

    Arne,

    that looks like the plan I had imagined. Use of the running tack line adds a lot of flexibility for weather/lee helm adjustment as I have found with Gypsy Rose. The boom can move forward until it is level with the waterline and this provides much more balance in the sail for off wind sailing. Looking again at the boat brochure this position should be forward of the forehatch and it should be fairly easy to reinforce the foredeck to support the loads from the mast.

    The revised mast position should allow better access for the V berth.

    If the rudder gets overpowered by the revised rig then converting to a transom hung rudder should be a fairly easy conversion and would give the rudder more of a lever arm as well as allowing a larger rudder with a good sized balance area ahead of the pintle line.

    Looking at the existing sail areas the main plus no1 genoa have an area of about 37 square meters and a spinnaker of about 50 square meters, so a somewhat larger sail area than Arne has shown, could probably be acceptable for optimum downwind performance.

    David.

    Last modified: 17 Jan 2023 20:47 | Anonymous member
  • 17 Jan 2023 11:47
    Reply # 13060459 on 13055766
    Anonymous member (Administrator)

    Inspired by David’s thinking, I had another go. This time I used the original Johanna 70 sailplan with the same batten length at 4.90m. This was initially installed with the boom overlapping that of the Johanna 60 sail. The mast was then moved forward 49cm until it crossed the 15% ring on the boom. This gave a comfortable halyard angle and increased halyard drift. I therefore lifted the whole sail 150mm to increase clearance over the rail and pulpit.

    On the wind, the steering balance should be very similar to when using that first sail .

    Downwind will call for more rudder input, but I don’t think it is a show-stopper. I have the same setup on my Ingeborg and I can easily sail downwind as long as I don’t set more sail than I can (just) carry when close-hauled.

    However, you can prepare the sail for a plan B  -  using running tack parrels and tack line to shift the boom forward, as indicated on the diagram in thin gray lines (here 5°). The preparation just means you have to make the fore batten pockets and batten parrels fitting the forward-swung position.

    The diagram shows that the initial boom rise of 10° ensures a decent clearance, even when swinging the sail forward.

    The new mast position will, as said, be 49cm forward of the first one (..the distance from bow to mast is now 1.89m..). That may take up a little more space in the V-berth. In case only one berth is to be used, the mast could be moved 120mm to one side, to clear the CL. My solution has been to pad the mast of Ingeborg.

    Finally, I have no idea of where any deck hatch is sitting. Maybe the mast in its new position clears the hatch.

    Arne

    PS: I haven't tried using a running tack parrel to shift the sail back and forth myself, but others like David have done so, and it clearly works.


    (Arne's album, diagram section 7, photo 8)

    Last modified: 03 Feb 2023 23:15 | Anonymous member (Administrator)
  • 17 Jan 2023 09:09
    Reply # 13060314 on 13055766

    Arne, Graeme and Jon,

    another alternative would be to move the mast forward to about the 10% overlap position using a steeper rake to the yard. This would provide reasonable access to the berths but would move the weight of the mast further forward and possibly exacerbate the weather helm. Off the wind the yard could be allowed to slide forward to the point where it was level which would increase the balance and reduce the weather helm, I use this technique on Gypsy Rose and it works well.

  • 16 Jan 2023 21:32
    Reply # 13059794 on 13055766
    Anonymous member (Administrator)

    Understood Arne.

    Just adding another thought, I looked at a very similar situation with my Pelorus (which I did not follow through on) and decided another possible solution might be to move the mast back to that bulkhead A  (which, hopefully is a structural bulkhead) and offset the mast just enough to clear the companionway.

    I Think it could be done in such a way that the companionway is wide enough and the heads area still viable. This would might bring the mast balance above 30% which would be into SJR territory?

    Its tight though, all the dimensions are close to the minimum required for things like swinging one's legs into bed, or sitting on the heads. 

    My main point is: many people would reject out of hand the idea of offsetting the mast - but if things are tight it might be considered. I would consider offsetting to port as I think it just might work (2) - or offset to starboard and do away with easy access to a little bit of storage space (3).


    Those doors could be rationalised - a single bifold door on the heads compartment might be part of the solution.

    Maybe only one single berth will be required in the forward cabin, that would ease things a lot.

    It's tight, but there will be a way.

    I do not believe off=setting the mast would affect the performance of the boat - Annie has done that with Fanshi, perhaps she will comment on any pro's or cons.

    Just discussion points, bouncing ideas.


    Last modified: 16 Jan 2023 21:39 | Anonymous member (Administrator)
  • 16 Jan 2023 18:26
    Reply # 13059514 on 13055766
    Anonymous member (Administrator)

    Jon and Graeme.
    Remember that my input was just a fast, first entry. This was to give Jon something to chew on. If he finds a better place for the mast and can tell me where that is, relative to the bow or to the shown mast position, then I can have second look at it, and hopefully find a solution.

    Cheers,
    Arne

  • 16 Jan 2023 17:05
    Reply # 13059313 on 13057781
    Deleted user
    Anonymous wrote:

    Just wondering though -  perhaps Jon should to do a mock-up of that arrangement, on the boat, to see if it remains possible to get in and out of bed in those two forward berths.


    Thanks Graeme - yes I think that's the next thing I need to check out. There are certainly some mast placements which would be problematic so I need to work out where the mast line as per Arne's suggestion would intersect with the accommodation!
  • 15 Jan 2023 03:19
    Reply # 13057781 on 13055766
    Anonymous member (Administrator)

    It looks good Arne. Just wondering though -  perhaps Jon should to do a mock-up of that arrangement, on the boat, to see if it remains possible to get in and out of bed in those two forward berths. I don’t have proper CAD software so I can't check the measurements very well, so I'm not sure, but I don't think my old bones could do it. The space seems pretty tight there.



    Last modified: 15 Jan 2023 10:33 | Anonymous member (Administrator)
  • 14 Jan 2023 22:11
    Reply # 13057572 on 13055766
    Deleted user

    Hi Arne

    Thank you so much for doing that - it is really helpful to have the benefit of your experience!

    I do like the idea of having more balance and hopefully reducing the weather helm. Whilst it’s not the main issue I also think that rig looks great on the boat!

    I should be able to get a reasonable idea of how the mast position would work by taking the position from that drawing and get an idea of whether it’s something what would work. 

    There is plenty still to think about, but definitely starting to see how it could work  

    All the best

    Jon


  • 13 Jan 2023 22:11
    Reply # 13056695 on 13055766
    Anonymous member (Administrator)

    Jon

    Your thinking behind wanting to convert your boat to JR, appears to be exactly the same as that which set me off converting my 23’ Malena in 1990.
    The masthead Bermudan rigs in those days were really slow downwind.

    I found the Leisure 27 on Sailboat Data. It surely looks to be a stout vessel with plenty of ballast.

    The smallish rudder is probably a result of making some of them with bilge keels. Now, just for fun, I had a go to see if one of my master sails could be adjusted to fit your boat.
    To remedy the small rudder, I have suggested two actions:

    • ·         I suggest you fit an end plate to the rudder, to reduce ‘wingtip loss’.
    • ·         I have drawn the sail with as much mast balance as I dare  suggest, here 25%. Luckily, in my library I already had a master sail of the “Johanna 60” type and AR = 1.99  -   basically a standard Johanna sail (AR = 2.00) with a new top section.

    This hi-balance sail will bring the CE closer to the mast, and thus give easier steering when reaching and running.
    The top view diagram also shows where the mast will hit the interior. You will have to decide where you can live with the mast.

    The suggested 37.7sqm sail area may not impress you, but my experience is that this area, set in one tall sail, is a good deal more powerful than a mainsail plus genoa of the same area. It would not surprise me at all if the JR will make your boat faster, even to windward.

    Arne




    (Arne's Album, diagram section 7, photo 6 and 7)

    Last modified: 03 Feb 2023 23:17 | Anonymous member (Administrator)
  • 13 Jan 2023 15:49
    Reply # 13055959 on 13055766
    Deleted user

    Thanks David - that's really helpful. 

    Yes I think calculating the current CE and looking at the potential mast position / rig type is the next step I need to look at.

    The DIY vs professional approach is also an interesting question, I would imagine it would be possible to spend a lot of money going down the professional route?!

       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

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