SJR H28

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  • 18 Jun 2018 11:04
    Reply # 6318071 on 6317975
    Daniel Powell Conti wrote:

    I am so confused! Half the websites I visit to try and understand lead say CE fore of CLR gives weather helm, the other half say the opposite!


    On my H28, by my calculation the CE is fore of the CLR, and I know my boat has just the right amount of weather helm.

    Generally on a monohull the CE needs to be ahead of the CLR. If the CE is too far aft this is what will give bad weather helm - I know all about this from experience!

    There should be quite a lot of information available for your H28, maybe through the NZ H28 Association. A line drawing showing the vessel profile and sail plan would be ideal and sufficient. From there you need a copy of Practical Junk Rig which will help you work out all the details you need, including CLR if that is not known.

    I think your idea of the SJR has some merit because this would allow you to probably step the mast in the current position, although I think the mast is deck stepped on an H28 (?). Another option might be an Aero-junk rig. If you go to a conventional junk sail plan you may need to step the mast well forward which will interfere with the fore hatch, or you may end up in the foredeck area where there will not be enough bury for the mast. Another option might be to go for the Fantail type sail such as on Fantail and Footprints, and step the mast further aft but rake it forward.

  • 18 Jun 2018 08:54
    Reply # 6317975 on 6316327
    Deleted user

    I am so confused! Half the websites I visit to try and understand lead say CE fore of CLR gives weather helm, the other half say the opposite!


    On my H28, by my calculation the CE is fore of the CLR, and I know my boat has just the right amount of weather helm.

  • 17 Jun 2018 23:58
    Reply # 6317585 on 6316327
    Anonymous member (Administrator)

    There are a couple of points of interest here which resonate with me, the first being the increase in sail area. Like Annie, I thought you might be getting a bit carried away with 48 sq m on an H28. I think the concept of being able to set more than the designed sail area in light airs, on the argument that the rig is easily reefed, is a good one, but there is a limit, a point of diminishing returns, and I suspect the limit is in mast height rather than sail area. In anything more than a light breeze you will only be able to carry what sail the boat will stand up to, so a faster boat is still going to overtake you. The burden of an extra metre of naked mast is going to be no help at all.

    There was a bit of discussion recently on one of the threads, about mast weight and how the weight of the rig comes down as you reef etc etc and I am not totally convinced by that argument (yet) but Arne came up with an interesting point about a few extra kilos aloft being merely the equivalent (in terms of static heeling moment) of one person moving to leeward in the cockpit, which has tempted me now to add an extra 1 metre to the length of the mast I am making. I am airing my ignorance here in the hopes that more knowledgeable members will correct me if I am wrong, but I think ultimately you do still have to consider weight aloft, and in addition you need to consider windage and rotational inertia (ie pitching and rolling). I think Arne has developed a plan form to achieve high sail area for a given height of mast.

    (On a practical level, from handling commercial fishing boats with and without even a relatively low mast, it is noticeable in a breeze how much a mast adds to the difficulty of stationing over gear, and handling in a confined space, while under power. And it is quite a sight to see a whole row of yachts tied up in a marina all heeling quite noticeably in a strong cross wind. I think windage might be the limiting factor on mast height, if it is not indeed weight aloft.)

    I hated the idea of a tall mast, but now, rather than theorise, I am making my mast a metre longer than I previously dared, and thinking to put an extra lower panel in the sail. We’ll see what happens. The idea is to be able to easily shorten the mast and modify the sail if it proves to be too much. I’ve got the makings of a long enough spar and hate to cut it short until I am sure, and I do like the idea of having a bit of extra sail area in light conditions.

    As I said, this might provoke a learned reply or two.

    The other point of interest is the tapered aluminium street pole. They don’t seem to have been available in New Zealand and if you succeed in finding one I think it will be of great interest here. Dave W has researched the question of importing one, and may be able to give you some leads. At least three local boats that I know of, in your size range, are making hybrid masts based on a standard 6m length of tube 152.4mm OD and 5mm wall thickness. These tubes are available locally and Annie has proved one already on a 26’ Raven which is roughly comparable with your boat in terms of mast requirement. She made a wood top section and is doing it again for her SIBLIM design. I am making an aluminium/aluminium hybrid using the top half of a large tapered aluminium flagpole, and Marcus has done it with a custom-made glass/composite moulding which might be the shot for you, if you find you have no option but to make it in two parts and have no workshop facility. I’m in West Auckland and contact details are on the website here. 

    Your first priority must be going for a sail with David – lucky you.


    Last modified: 18 Jun 2018 01:23 | Anonymous member (Administrator)
  • 17 Jun 2018 19:53
    Reply # 6317398 on 6316327
    Deleted user

    Thank you all for the welcome!

    Yes David, I would love to sail a junk rigged boat! I have never sailed one actually, or even seen a rig up close. I am pretty busy for the next few weekends but I will certainly be in touch.

    Graeme, I remember seeing their boat up in the BoI last summer. We anchored near it for a few days actually. It slipped my mind until your comment and their name and photo in the latest JRA magazine reminded me. A beautiful boat. Where abouts are you based? I am at Herald Island.

    Thank you for the suggestion Annie. I pondered the extra area because I was a little miffed at being overtaken all the time, even though as I live onboard I actually will have a decent sized kitchen sink soon enough :) I contemplated a hybrid mast but pure aluminium would save having to find a workshop. There is/was a junk rigged catamaran moored around Okahuiti creek at Waiheke with these hollow masts, presumably made out of wood. They had steps cut into the aft facing section. Never seen anything like them. I will be sailing for a longer time in a few weeks so will go and get some photos if it is still there.

  • 17 Jun 2018 07:03
    Reply # 6316774 on 6316327

    If you are Auckland based, or even further away, and would like to come sailing on a junk rig boat, and gets some ideas, you are welcome to come out on my yacht for a sail. I am based in Mahurangi just north of Auckland. See my profile for my email contact. 

  • 17 Jun 2018 01:57
    Reply # 6316480 on 6316327

    Hi there

    Great to have another Kiwi member in the JRA. 

    At the end of the day, you may find it easier to go for a hybrid mast - for the sail area you are contemplating, you will need a pretty hefty section.  However, it will be great to hear if you discover an alternative.

    I think that most of the GRP H28s in this country sail a wee bit on the stodgy side because they tend to have 'everything but the kitchen sink' on board.  So removing some of the excess weight would be a good start.  I'm a great believer in having plenty of sail area - I hate motoring - but we don't suffer too many extended periods of calm weather here.  I think 40 sq m would be ample - 48 more than a little over the top.  It will be interesting to have a couple of split junk rigs up and running here.  Keep us posted!

  • 16 Jun 2018 21:58
    Reply # 6316347 on 6316327
    Anonymous member (Administrator)

    Great. The H28 will make a great conversion I think. You might be interested in a recent conversion of a little sister to the H28 which was done by Linda Crew-Gee and Pete Hill. Anyway, I am half way through converting a boat about the same size as yours (but will probably never perform as well as yours) also planning a SJR and also a live-aboard in Auckland. 

    You are looking at a big increase in area, you may find that to get maximum area and maximum simplicity the high-peaked Arne type of sail is worth consideration. I have found that the SJR is not quite as simple and does need a taller mast to get a comparable area. No doubt Arne and others can advise you about that. Feel free to contact me off line it would be good to share ideas with someone else in Auckland.

    Last modified: 16 Jun 2018 22:08 | Anonymous member (Administrator)
  • 16 Jun 2018 21:29
    Message # 6316327
    Deleted user

    Greetings from Auckland!


    My name is Daniel, longtime floater on the public forums, newtime member.

    I have been an imaginary junkie since 2013 when I first came across the idea. Imaginary in the sense that I had no boat and couldn’t sail. It would be another three years before I sailed my first boat, an Alan Wright Variant, and another two years before I would have both a boat and the money required to contemplate a project. Which brings me to now, the proud owner of a H28 and a liveaboard.

    This website has done a lot for me to keep my imagination smouldering over the years, so thank you all for your input and expertise.

    The project: 

    I have begun to contact street light manufacturers in NZ looking for one that can provide me with a tapered pole with a 5mm wall thickness and a decent diameter. I will let you know how it goes.

    My intention is to build a sail with a bit more sail area than the 33sq m that the H28 comes with, between 40 and 48 should give me a boat capable of some impressive speeds for Gulf Cruising.

    Mt intention is also to eventually sail this boat around North Island, hopefully South Island too, but that will be a few years away!

    My feeling is that the SJR is a perfect combination of performance and simplicity.

    I will keep you up to date with my calculations and diagrams while I catch up on my reading on the intricacies of rig design.


    I just wanted to say hello and thank you! :)

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