Maxi 77 junk rig conversion

  • 16 Jan 2024 22:29
    Reply # 13301939 on 13226713

    Hello Istvan !

    Here are their (Rosa) addresses:

    https://rosa.pl/en/contact

    You must roll down, then press any "V" sign on the right side (drop-down list ) ;)

    take care ! Vigyázz magadra !

    Jan

    EDIT:

    My junk guru Kris Matuszewski used aluminum power poles bought somewhere in Poland. Kris should be arriving in Lanzarote soon, so if you would like to contact him, he may be available on Facebook for some time.

    Last modified: 17 Jan 2024 11:59 | Anonymous member
  • 16 Jan 2024 16:17
    Reply # 13301703 on 13301177
    Anonymous wrote:


    Hello István,

    welcome to the JRA!

    My advice is to contact Nedal. Just click on "Lighting columns" and select Hungary:

    https://www.nedal.com/contact/sales/

    Frank

    Dear Frank!

    I've contacted them for a price offer through an Austrian distributor, they seemed heplful, we'll see the price.

    Until that: what density and type sailcloth do you recommend? For now I'm leaning towards sewing a flat cut sail myself (I've sewn a few for my self built small boats). Maybe Paul mentioned that he had sailed with a junk rigged boat with a way too heavy sail and it had zero windward performance. What I liked working with and has a friendy price tag is a 380 g/m^2 polyesther cloth with PU coating on one side, I don1t know if it's appropriate for a sail like this.

    On the other hand we have predominantly light winds in the summer on Lake Balaton, Hungary, so I'm still browsing info about cambered sails, and if I can sew one myself, or I should contact the sailmaker I know.

  • 15 Jan 2024 15:21
    Reply # 13301177 on 13301116
    Anonymous wrote:

    Hello everyone,

    Anyway, it's just all dreaming until I can find good mast material. I definetely want aluminium, what I probably can source in Hungary are made by Polish company, Rosa (rosa.pl), but I can't find their email adress. Maybe I could reach them via their Hungarian dealers, if it worth the hassle.


    Hello István,

    welcome to the JRA!

    My advice is to contact Nedal. Just click on "Lighting columns" and select Hungary:

    https://www.nedal.com/contact/sales/

    Frank

  • 15 Jan 2024 11:39
    Reply # 13301116 on 13226713

    Hello everyone, hello Paul!

    I'm new to the JRA, but after reading some of Roger Taylor's books, watching YT videos and reading the availabe material on this site, I got really interested in converting my boat, which is also Maxi 77, hull number 1619, into junk rig. I read this whole thread and found interesting information, I actually thought that installing a free standing mast requires more reinforcements.

    Anyway, it's just all dreaming until I can find good mast material. I definetely want aluminium, what I probably can source in Hungary are made by Polish company, Rosa (rosa.pl), but I can't find their email adress. Maybe I could reach them via their Hungarian dealers, if it worth the hassle.

    https://rosa.pl/produkt/sal-115m-p

    This is a two-part pole, ordering a raw upper part would only be 9888 mm according to their bluerint. IF they are willing to ship a raw upper part at all.

    https://rosa.pl/produkt/mal-12-5

    This one is a bit overkill according to the previous posts, but I don't mind extra safety, althought moving it on the ground would be a real challenge for two people.

    What do you suggest? Does it worth trying to reach out for the company?

    PS: Paul, whatever you do, don't start scraping out the glued inner liner!

  • 06 Dec 2023 20:25
    Reply # 13287931 on 13226713

    A quick note on Aluminum alloys and their strength. It appears that Nedal, for example, uses "at least" values while some of the sources I gave use "typical" values. At least that seems to line up well with this wiki article. I would guess some of these differences have to with where in the world the metal is alloyed and how accurate the the process controlled. Suppliers who control their own source may feel confident using values they can achieve, while importers would have to use the "at least" value.

  • 26 Nov 2023 22:42
    Reply # 13283653 on 13283624
    Anonymous wrote:Gulf of Triest this Sommer,  18 Kn gusting 24, little steep waves 0.4 m. I started conservatively to avoid too much stress on her 40 years hold spar. With 4 panels up we were making poor progress upwind. I wondered if the boat was under canvassed so I raised the 5th and the 6th panel. The boat heeled to 15 degrees, stiffened up and started to go upwind properly. The mast bended at any gust.

    I think every boat has a heel angle that tells when canvas is maxed out. Mine is at about 10 degrees, the previous owner says the boat he owned before this one was happy at 15 degrees. So it sounds like you were probably canvased correctly. With my boat, 10 degrees will get me up to hull speed, so no need to add canvas but my boat is probably heavier and stiffer.

    My alloy mast is a folding one. The dimensions are 10 cm diameter at the base and 6 cm the top. The joint between the

    ...

    measures 10 cm at the base and 6 cm at the top. Hasler itself developed the rig of the KF 20+ and sailed his own KF 20+ "Pilmer" upwind in F6-7 "in steep breaking sea" (see article below) without breaking the rig. Surprisingly, according to PJR the mast for a Kingfisher 20+ with a 21 sqm sail should measure 20cm at the base!

    I think that is what a lot of people are getting at, the PJR is well over built. I think part of the difference is wood vs. aluminum. Well, that is not quite right, woods strength as quite well known but wood is in general, no uniform for any one kind of wood. It depends on where it is grown, how it is dried, how or if it is glued together, where the knots are, etc. PJR does most of it's calculations based on wood with, I would imagine, extra strength built in to compensate for wood flaws. (or maybe extra strength just because it is someone else's boat and they feel responsible for it)

    I wonder how "alarmingly" is really a thin bending mast on a coastal cruising boat...

    :)   That is why I have been quoting that word, 'cause I don't know.

    A thin mast would mean less parasitic drag on the starboard tack and less sail distortion on the port tack (am I right?) and while bending it could absorb gusts smoothly.

    As with anyone, I want as little windage as I can get but a broken mast has no windage at all.

    Could be a thin mast made of carbon fibre a good solution for a coastal cruising boat? 

    I trust my carbon fibre skills as somewhat less trustworthy than my wood butchery skills  :P

    Aluminum, with no welding or other fastenings, gives me something that is the least likely for me to mess up.

    P.S 2:  sorry for parasitizing this thread again :)
    I think by now we have T-shirts for that.
  • 26 Nov 2023 20:39
    Reply # 13283624 on 13226713

    My little experience about mast bending on my KF 20+:

    Gulf of Triest this Sommer,  18 Kn gusting 24, little steep waves 0.4 m. I started conservatively to avoid too much stress on her 40 years hold spar. With 4 panels up we were making poor progress upwind. I wondered if the boat was undercanvassed so I raised the 5th and the 6th panel. The boat heeled to 15 degrees, stiffened up and started to go upwind properly. The mast bended at any gust. My alloy mast is a folding one. The dimensions are 10 cm diameter at the base and 6 cm the top. The joint between the upper part and the lower one is covered by a sliding alloy tube. The lower part of the mast is quite stiff while the upper part bends. I have a second original mast in one piece which measures 10 cm at the base and 6 cm at the top. Hasler itself developed the rig of the KF 20+ and sailed his own KF 20+ "Pilmer" upwind in F6-7 "in steep breaking sea" (see article below) without breaking the rig. Surprisingly, according to PJR the mast for a Kingfisher 20+ with a 21 sqm sail should measure 20cm at the base!

    I wonder how "alarmingly" is really a thin bending mast on a costal cruising boat...

    A thin mast would mean less parasitic drag on the starboard tack and less sail distortion on the port tack (am I right?) and while bending it could absorb gusts smoothly.

    Could be a thin mast made of carbon fibre a good solution for a costal cruising boat? 

    Ciao

    Mauro

    P.S: I see now that in the picture below the mast of Pilmer seems to bend backwards :)

    P.S 2:  sorry for parasitizing this tread again :)

    2 files
  • 26 Nov 2023 18:39
    Reply # 13283606 on 13283573

    . I would also point out that you are using two poles, so the masts might be 6% all together?

    No, Len, that's the weight of both masts added together that is about 3% of total weight.


    I have heard that the trip from Mexico back to BC is less fun. Out to Hawaii and then BC seems better though still rough, still the current is the right direction. But time is the biggest factor right now. We shall see what the future brings.

    Yes, no doubt!

  • 26 Nov 2023 16:25
    Reply # 13283573 on 13283523
    Anonymous wrote:

    For my boat, I have decided that because the stronger of the two masts I can realistically build is still only about 3% of my displacement anyway,

    And Arne wrote: These days I am content that I can design an amply strong mast, which adds no more than 3% to the weight of the boat.

    An interesting discussion! I designed and built my masts using PJR minus 10%. They're built in basically solid spruce (there's a 5cm square hole up the middle) and glassed with some fairly heavy biaxial cloth in epoxy. With fittings, they come out at almost exactly 3% of boat weight. My first impression is that they are very strong and I have seen no obvious flexing when sailing (to date).

    Hmm, more to think about. Arne's formulae, that we are using, are already lighter than PJR. I would also point out that you are using two poles, so the masts might be 6% all together? On the other hand, no matter how many masts one uses, the righting arm remains the same, meaning the mast still has to be just as strong even with less sail area on the mast (my brain hurts). On the other hand, the Sunbird masts appear to be too thin/light. Not only do they bend "alarmingly" but it seems they do fail with use. I am not inclined to use wood as my wood butchery, while good enough for many things, is not something I would trust for a mast build. Aside from my own failings as a builder, making sure the wood has no flaws in it is another concern.

    Len wrote: I don't expect we will cross the Pacific (even half way to Hawaii) or travel the coast to Mexico.

    I did travel the coast from BC to Mexico, in a boat with a grown mast that was significantly lighter than PJR minus 10%. It was fine!

    I have heard that the trip from Mexico back to BC is less fun. Out to Hawaii and then BC seems better though still rough, still the current is the right direction. But time is the biggest factor right now. We shall see what the future brings.
  • 26 Nov 2023 08:22
    Reply # 13283523 on 13283311

    For my boat, I have decided that because the stronger of the two masts I can realistically build is still only about 3% of my displacement anyway,

    And Arne wrote: These days I am content that I can design an amply strong mast, which adds no more than 3% to the weight of the boat.


    An interesting discussion! I designed and built my masts using PJR minus 10%. They're built in basically solid spruce (there's a 5cm square hole up the middle) and glassed with some fairly heavy biaxial cloth in epoxy. With fittings, they come out at almost exactly 3% of boat weight. My first impression is that they are very strong and I have seen no obvious flexing when sailing (to date).

    Len wrote: I don't expect we will cross the Pacific (even half way to Hawaii) or travel the coast to Mexico.

    I did travel the coast from BC to Mexico, in a boat with a grown mast that was significantly lighter than PJR minus 10%. It was fine!

       " ...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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