Carbon mast with 6,2 meter length ?

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  • 24 Aug 2019 03:28
    Reply # 7846046 on 7799739

    It looks as though you have done a really nice job of making the mast.

    Its interesting, I used exactly the same stainless steel saddles on my masthead, to carry the halyard, lifts etc. (But I was impatient and did not glue wooden packing in the inside to strengthen the fastening - that detail shows you are skilled, patient and experienced I think.) What is interesting though, is I am finding the saddles do not work very well for me. The halyard binds and develops more friction than it should, and in my case I am thinking it is partly because those saddles encourage the blocks to lie hard against the mast and not swing out a little as they should. I think I am going to have to replace my saddles with fittings that act more like a crane and hold the blocks out just a little. My halyard is a 4-part tackle, starting at the yard, going to the mast, back to the yard, back to the mast and then down to the turning block - yet I still struggle to raise the bundle. I guess my sail is heavier than yours and needs a better halyard arrangement (and a better actual halyard, as I am still using the original trial halyard made of rubbish rope.)

    When you get a photo or two of the interior, will we be able to see a magazine article which describes how you chose, built and sailed your little boat?

    Happy sailing

    Last modified: 24 Aug 2019 03:29 | Anonymous member
  • 23 Aug 2019 18:32
    Reply # 7845458 on 7799739

     My boat has practically 4 bunks but I will not use her for overnight camping, just for day sailing and towing her home in the evening. I fitted the mast head according to Hasler PJR book. The halyard 30 degrees to port, the fitting for mast lift PS and the burgee halyard SB and 2 topping lift fittings PS and SB at 45 degree angle towards the bow. One forward fitting I mounted to be able to  have at a later stage a ghoster sail with a bow sprit. I glued pieces of plywood with epoxy inside the mast head so I could screw each fitting with 2 screws and a nut to the mast top. I closed the mast top for a start with a plastic lid tied down with a reef knot because I could not think of anything better .

  • 21 Aug 2019 02:47
    Reply # 7838927 on 7799739

    What a charming little boat, and your big smile says it all.

    Supporting the mast in this way is the usual method for trailer boats in my country. Some can even swing the rudder blade vertical and mount a little support fitting on it for the mast, but usually it is just some kind of strut which replaces the rudder and attaches to the rudder fittings. Your mast looks so slender and light, I am envious.

    I am really looking forward to some photos of her sailing in a good wind, some details of how you have set up halyard, lifts etc - and maybe an article in the magazine?

    Will she be used for overnight camping?

    Is Wilde Qualle  flat bottom or V bottom?

    Happy cruising to you and your family.

    Last modified: 21 Aug 2019 02:54 | Anonymous member
  • 19 Aug 2019 11:10
    Reply # 7835446 on 7799739

    Hi,

    My carbon mast is finished and I made it the way you guys advised me it is glued completely so I have to transport it on two supports one in the mast hole and the other at the rudder fittings. I painted it with one coat of primer and 2 coats of white boats paint except the very top near the mast head because this part has clear varnish to protect it from UV rays. My son went sailing with me on Saturday and he raised the mast and put it through partner into the shoe within 20 seconds. There was practically no wind but we still enjoyed the time on the water. The third picture is a bit far away taken from the lakes shore but one can recognize the junk rig.

    Greetings from Karl


  • 08 Aug 2019 11:50
    Reply # 7818107 on 7799739

    Hi,

    Today after 2 sleepless nights because of thoughts about glueing my carbon mast pieces I did it at last and it took very little time. I think building my boat has taught me preparation for any task is the key to easy execution.
    I first stuck on the 2 inserts lots of plastic tape around it like on the first picture in the attachment until it was the same diameter as the long pipes to make sure that it is completely straight lying on the table after gluing and then I mixed 25 grams of epoxy with 14 grams of hardener 3 teaspoons of silica and one spoon of wood flour and brushed first the insides of the long pipes and then the inserts themselves and slid them together wiping any excess epoxy away finished in 10 minutes. The second picture shows both pieces glued into the long pipes. 24 Hours of curing and I know if I did a decent job.

    Greetings from Karl

  • 29 Jul 2019 11:11
    Reply # 7801039 on 7799739

    Hi Graeme and David,

    Thank you so much for your suggestions for my mast. The rotating idea like all my other junk rig wisdom I have of Haslers book Practical Junk Rig but he talks of the whole mast rotating. I think I will glue it in the middle and transport it on top of the cabin roof. Yes Graeme the outside pipe is the one you quoted while for the inside pipe I bought this:

    0371CTPP5046-1 Carbon Rohr 50x46x1000mm
    Außendurchmesse : 50mm
    - Innendurchmesser : 46mm
    Länge : 1 meter- Gewicht : 465g/meter.
    Aufbau : PRE-PREG TECHNOLOGY, Epoxitharz.


    I think the pre-preg technology is the better quality produced carbon pipe as it is also a third more expensive. I will test the bending of the whole mast in my boat shed by putting pressure at the mastheads position and have it fixed at mast partner and shoe position and in addition I will find out the exact bending force specifications from the French supplier. My gut feel so far is that the 3 meter pipes are as stiff as steel and practical the same as my yard and boom which I made myself out of a combination of fiberglass and carbon sleeves and epoxy. Some leftover carbon sleeve I will use at the joins of the mast at the head and in the middle and if I got some left I will strengthen the mast with it at the partner. My next report will hopefully be with pictures of what I have done besides juggling the ideas in my head.

    Greetings from Karl




    Last modified: 03 Aug 2019 11:30 | Anonymous member
  • 29 Jul 2019 00:02
    Reply # 7800705 on 7799739

    Hi Karl it seems that wind surfer masts are usually made from carbon fibre, small diameter tubes with an internal sleeve join. This one is 4.5 metres when assembled.


    Mind you, I think they are supposed to be quite bendy, you won't be wanting that much bend. The point is, the join detail does not seem to be a problem.


    I presume this (below) is your outer tube?

    0372CTW550510-2Carbon tube 55x51x2000mm Outerdiameter: 55 mm-Innerdiameter:51 mmLength: 2 meters- Weight: 533 g / meter.Construction:pultrusion, inner fabric 80 ° + single direction + outer fabric 37 °, epoxy resin.

    Since you have already bought the tubes, why not just give it a go?  If it breaks at the join (or at the partner) you can fix it, and make it stronger.

    Last modified: 29 Jul 2019 00:19 | Anonymous member
  • 28 Jul 2019 23:18
    Reply # 7800670 on 7799739

    Hi Karl,

    carbon fiber tubes are made mostly of unidirectional material with little material binding it together to stop it from bursting. When sleeved over the lower section your upper section of pipe will experience significant pressure that is liable to split the pipe at the join. A glued joint with a binding of CF around it would be much more likely to survive the forces at the joint. I suggest that you contact the supplier and verify the layup of the pipe, and its actual bending strength for the purpose that you are putting it to. I have doubts that it is strong enough where it passes through the deck. A rough calculation of the expected force is the sail area in square meters multiplied by the wind force of approximately 5 kg per square meter at 15 knots of wind, applied at a distance of deck to center of area of the sail plan.  Once you have calculated this force multiply by at least two for a safety factor. Then compare to the bending strength of the pipe. The manufacturer should be able to give figures for this.

    All the best with the project, David.

  • 28 Jul 2019 20:53
    Reply # 7800523 on 7799739

    I think the amount of overlap (bury) is 30cm and therefore within the approximate 10% which is regarded as a minimum for tabernacles, so in theory the join itself should be as strong as the rest of the mast, in bending. However there is still the problem that the halyard and yard will put a rotational force on the top of the mast. It would be interesting if the top section of the mast was able to rotate. I  have never heard of that being done, (though I have seen on other more simple rigs, rotating masts where the entire mast is allowed to rotate in the partner.) I suspect that with all the running rigging which is usually carried on a junk mast that rotation of the top part would be unacceptable, but I don't know from experience. Maybe the top part, if not glued, would need to be secured in some way so as to prevent rotation, but I am not sure the best way for a carbon fibre tube. Hopefully someone else who knows more than me will chime in here. 

    I had a sailing dinghy a few years ago, in which the mast came apart simply, in two parts. It was no problem, quite convenient in fact, but it was a very simple sail.

    My own thought would be to glue the mast fully and just accept that when trailing the boat, the mast will need to be carried over the top of the cabin and will protrude forwards and aft, a little, which is the usual way for a trailer sailer.  However there is room for some other ideas here. Your little boat is very interesting and when you get her sailing, some more photographs and a description would be very good.

    Last modified: 28 Jul 2019 21:30 | Anonymous member
  • 28 Jul 2019 11:54
    Reply # 7800130 on 7799739

    Hi Graeme,

    Thank you for this idea. I want to try not to glue the top half of the mast at all just slide it over the glued in and cured 30 cm sticking out of the lower mast half and put it together for sailing and when the boat is on the trailer I can store both mast parts in the hull. Please do let me know what you think of that.

    Greetings from Karl

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