Mast position

  • 11 Oct 2026 12:48
    Reply # 13739172 on 13709997

    Hi Andrew, I agree the being able to use the forward hatch is a great feature on the Sabre 27 and in designing my installation I retained that feature. It did mean positioning the mast in the deck area immediately in front of the doghouse as had been done before on the boat fitted out by Sunbird Marine. However, this position is a bit too forward according to the PJR book and caused me problems as described later.

    The sailplane used on the boat from Sunbird Marine (Sunbird 80's rig as illustrated in PJR) appears from photos to have an AR of 2 of greater with the sail is sheeted to a traveller on the bridge deck by the companionway as per usual arrangement for the BR rigged Sabres. In conversations with  Robin Blain he explained that the boat initially  suffered from extreme lee helm which was corrected by raking the mast aft 3 degrees. I also raked my mast aft by the same amount to meet the PJR recommended CE position of the sail relative to CLR of the hull. However, as mentioned in my earlier posting my original flat cut HM sail AR1.5 batten length 5.5m generated to much weather helm when off the wind which was corrected by recutting the sail, AR 2, all battens & Boom 4.2m. The mainsheet blocks are attached to a bridle across the transom. The CE of the recut sail coincides with that of the BR sloop.

    I had considerable freedom in the fitting out of my boat because I was starting from a bare hull & deck moulding which had been stored in a barn for 20+ years by the original owner and  was in 'as new condition' according to the pre-purchase survey. No work had been done by the original owner mainly due to business commitments.

    To distribute the weight towards the centre of the boat  I positioned the water tanks (2x 62liters)  over the bilge keels, as opposed to fitting a 120litre flexible tank forward as per the conventional Sabre arrangement. I thought this might compensate for the compromise with the mast position and associated weight more forward than ideal.

    Further, I was able to move the heads compartment aft to starboard besides the companionway taking advantage of the offset companionway.  This arrangement enabled me to create two full-length single bunks forward with an infill panel to convert to a large double berth which is our usual set up. I also repositioned the anchor locker bulkhead further aft immediately in front of the mast to strengthen that area. The anchor locker  drains overboard.

    I do have an ongoing issue with the forward position of the mast which with my current anchoring set up which makes my boat too bow heavy and negatively affected the motion of the boat upwind in anything but smooth water.  I am currently using an all-chain rode which together with an anchor totally 100kg+. Last year, to reduce weight up forward, I tried a rope/chain rode but just didn't feel secure overnight and the amount of scope required was problematic if there were other yachts at the anchorage. I'm now planning to move the chain locker aft and directly above where the head compartment is located for the conventional Sabre 27 layout.

    You commented that you're  on a tight budget, so was I, which accounts for my taking 15 years to complete the fit-out! I hope your project can be completed sooner. I've uploaded a photo to give a better impression of the layout.

    Best wishes, Frank

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  • 10 Oct 2026 16:13
    Reply # 13738050 on 13736329
    Anonymous wrote:

    Another thing to remember is that some members have reported good success with quite high balance contiguous sails ( ie, NOT SJR), 

    Thanks David. It's a bit like juggling with 5 balls in the air!
  • 10 Oct 2026 16:11
    Reply # 13738046 on 13732823
    Anonymous wrote:

    Hi Andrew, I read with interest your intention to fit a Junk rig to a Sabre 27. I fitted out, from a bare hull, a Junk rigged Marcon Sabre 27, twin keel. To my knowledge my vessel was the second Sabre 27 with a junk rig. 

    Thank you Frank. That is very interesting (and encouraging). The obvious way to do it would be to treat the whole area in front of the existing mast as available, but I'm afraid I find the forward hatch so useful for ventilation, access, dropping grandchildren into, etc. that I am not prepared to lose it, so the design will have to take account of that. 
    I'm afraid, at the moment, I'm a bit like a rabbit in the headlights, so much information, so little personal experience. I haven't even got beyond the mast construction yet, which is hampered by the miniscule budget.  I'll get there but its currently very slow progress.
  • 09 Oct 2026 15:27
    Reply # 13736329 on 13709997

    Another thing to remember is that some members have reported good success with quite high balance contiguous sails ( ie, NOT SJR), so even if the best mast position for your needs is not suitable for an SJR, you may still be able to build a quite high balance one-piece sail to get some of the benefits of better balance, going downwind. 

    I think Arne has some lower-yard-angle higher-balance sails in his portfolio, though you do lose some luff length and sail area for a given mast length. 


    Just a thought. 

  • 07 Oct 2026 22:14
    Reply # 13733407 on 13709997
    Anonymous member (Administrator)

    It would make more sense to provide a scale drawing of your current sail plan.

    You should aim to geometrically match the proposed junk rig to the original Bermudan sail plan (that is, the geometric centres or CEs of the two sail plans should match), if you want approximately the same helm characteristics from a cambered panel junk sail.

    I don’t know whether or not this drawing is true to scale, or whether it represents your version of the Sabre 27, but at face value and doing some rough calculations: to match that sailplan a SJR (33% balance) should have its mast at least 30" - 33” forward of the above mast position.

    Having said that, I don’t necessarily trust the Sailboatdata drawing, having seen an example which was considerably in error. If your drawing would show the current mast position, and the planform of your current rig, the calculation for mast position of any junk rig is fairly simple.

    (The hands-on experience of Frank is valuable in this regard too, taking into account the bilge keels, his flat-cut sail and the tendency of the boat to acquire weather helm when heeling).

    I don't include myself in the expert category at all, and I don't have the means for accurate drawing, but my guess is 22" is likely to be marginal to say the least, even for SJR, if the above drawing can be believed. 

    Maybe you could consider what is a fairly commonplace conversion: take the mast down through the forward hatch, offset a little, and lose one of the forward berths. That would open up a range of JR options. There are plenty of documented examples of thru-hatch arrangements, for example Jes's Mwera conversion (JRA Magazine #100 March 2026).


    Last modified: 07 Oct 2026 22:45 | Anonymous member (Administrator)
  • 07 Oct 2026 15:48
    Reply # 13732823 on 13709997

    Hi Andrew, I read with interest your intention to fit a Junk rig to a Sabre 27. I fitted out, from a bare hull, a Junk rigged Marcon Sabre 27, twin keel. To my knowledge my vessel was the second Sabre 27 with a junk rig. The first was by Sunbird Marine, which is no longer trading following the death of Robert Blain the founder of the company. Sunbird Marine also fitted out other hulls with junk Rigs. 

    Robert shared his experience regarding positioning of the mast and components used ( partners, mast clamp for attaching blocks to lead running rigging aft to the cockpit, etc). Sunbird Marine fitted alloy masts from Hawk Marine Services. This company took over production from Needlespar and built masts to that design. Hawk Marine built my spar.

    I opted for a HM flat sail, alloy battens and boom. Purchased a length of dinghy mast from Z spars and associated fittings to make the yard. I had the sail made professionally.

    Regarding mast position, I followed Sunbird's example and positioned the mast just forward of the doghouse. I was working with a bare hull and redesigned the interior layout, specifically for the first mate (wife) and myself. Our boat has a large double berth f'd with a large  hatch above, as per the original design of the Bermudan rigged boat and I wished to retain that feature. 


    I appreciate that you wish to retain the original mast position and accordingly are considering a split junk rig. The CE of my current sail coincides with that of the BR sloop. My original sail was 35m^2 AR 1.5 but although fine upwind, it generated too much weather helm when off the wind particularly with the wind aft of the beam. I had designed the rig to enable canting of the sail across the mast for off-wind sailing  but this was not enough to remedy the excessive weather helm in winds F4 and above when off-wind. I had 1m cut off the leach and this significantly improved the situation. There is a touch of lee helm when close-hauled in light winds but I find this acceptable and once the boat heels this disappears. My current sail is 30m^2 which is a bit too small for light airs but generally fine for the west coast of Scotland where I've been sailing this season.

    I hope you find the above helpful and if you wish for more detail, I'm pleased to assist. 

    Best wishes, Frank

  • 22 Sep 2026 08:03
    Reply # 13711603 on 13709997

    This begs the question: "enough for what?" 

    We know:

    1. that SJR has a mast position quite well aft, so probably enough for that.
    2. that a wingsail similar to mine has the least balance, so probably not enough for that.
    3. that in between those extremes, one of Arne's sailplans can probably made to work.
    4. that a higher AR generally results in a mast position further aft.

    You've demonstrated that you can make a drawing, so now it's time for you take ownership of, and responsibility for, the design process, and rustle up some initial design sketches with that knowledge in mind, and with some idea of what kind of rig you would like, to suit your style of sailing - relaxed family cruising, as I understand it. If you can  make and show us these sketches, we'll have something to comment on. 

  • 21 Sep 2026 17:32
    Message # 13709997

    I've measured the available space on my Sabre 27. I can move my mast position forwards by approx. 22 inches. Is this likely to be enough? This is the current position.

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