Help hotdog

  • 01 Nov 2020 20:08
    Reply # 9338962 on 9327660

    Graeme!

    Anchoring my mast to the deck step is my plan. I remembered reading that Arnie had lashed his down in some maner witch sounded interesting. I like to lash things, hahahaha. I'm in touch with Zane and hope to plan a race once I get to Australia. His contessa looks amazing! The guy has some mad skills!


    Uele!

    I'm sold. I'm going with the 7/32" mast. There is a 6 month back order on it but it is made locally with makes me happy. Thanks so much for the advice. I was told that I need to have a 4-5 in well for the mast steep. I can only go down 3 inches below the original height of the floor. It's going to be tight getting around the 8 in mast as it is. Do you think I can get away with the 3" Barry or do I need to build it up?


    David!

    Thanks for the advice. That sounds like the easiest way to go about securing the mast. Wold you recommend a size hole for both the mast step and partner? (the mast is 8 in. OD) The mast will have fiberglass under it and I'm planning to epoxy the end grain in the wholes, but should I glass it as well? I have been told putting some Spartite into the mast step helps reduce squeaking noise. Sho I leave a little wiggle room to allow for the Spartite?


    Karl!

    I most definitely do not need my mast to rotate. I'm going to go with Davids advice on this one.why do you have yours rotate? Also, I'm planning on running my electronics through the bottom of the mast. The plan is to drill a 1 in hole down through the floor of the mast step and glue a funnel into the bottom of the mast to help direct the wire into the hole. The floor of the mast step will be floating 2 in off the keel to allow water and electric lines to move forward and aft of the boat. Also to keep standing water from contacting the plywood that the mast step is made of.

  • 31 Oct 2020 08:04
    Reply # 9337064 on 9327660

    Hi Jeffrey,

    As I mentioned before as a weekend and inland sailor beginner at age 74 I am no good to give advise to ocean sailors. I just gave my opinion which was very wrong with the idea of holes near the partner where some collegue mentioned that the mast needs to be very strong there.

    My collar is like a big hose clamp holding the mast very tight in position and I made it so that the mast can rotate which you most probably do not want at all. So once Your mast is raised , fix it just near the mast foot where you maybe need a hole for mast head lights wiring anyway, or is that done above deck together with the lightning cable ? You see the layman is at it again, so do listen to experienced sailboat builders and have fun building on.

  • 31 Oct 2020 08:02
    Reply # 9337048 on 9327660

    Jeffrey,

    The easiest thing for you to do, I think, is to make two L shaped brackets of 1.5" x 0.125" aluminium strip, or something close to that, screw them down to the mast step with two #14 screws each, and drill a hole that passes through both brackets and the mast so that you can pass a 0.5" dia aluminium bar through, with split pins through it to hold it in place. The bar can be fore and aft or athwartships, depending on what furniture gets in the way. This takes care of rotation and rising, and it's easy to withdraw the bar to unstep the mast, whereas if you screw to the mast, corrosion will make it difficult to get them out again.

    Aside from normal sailing loads, the worst a mast sees is a good shaking when passing through tidal races off headlands, that sort of thing. Out in the ocean, that doesn't happen. A knockdown or blow down to horizontal is possible, even likely if you sail in latitudes where storms stronger than gale force occur, and a good rig will take that in its stride; but a rollover is extremely unlikely to happen unless you go down into the southern Ocean, and if it happens, there is no way of ensuring that the rig can survive it - the forces are unknowable. Set that thought to one side, and concentrate on getting a rig that can take the day to day flexing over thousands of ocean miles that will cause fatigue in too weak a mast.

  • 31 Oct 2020 07:27
    Reply # 9337026 on 9327660

    hi jeffrey

    the 7/32" mast should provide a strength around factor three of the righting moment – looks good to me! and 150lbs is a little less than 3% of the boat weight. this looks ok as well.

    if you need a hole in the mast to keep it in place, drill it in the lower 6-8" and you will be fine.

    ueli

  • 31 Oct 2020 01:23
    Reply # 9336741 on 9327660
    Anonymous member (Administrator)

    My understanding is that the mast needs to be fixed at the heel, so that it can not rotate - and so that it can not jump out of the mast step, or even worse and punch through the bilge, due to violent pitching (as happened to David Lewis down here, many years ago).

    If you attend to that properly, and its fairly simple, how then can the mast ever move due to rolling, or even capsizing? 

    At the partner, or deck level, the mast needs lateral support - the partner/deck structure must be strong - and a detail to close the gap and prevent water leaking in such as spartite (or equivalent) - or wedges and a mast boot as described by Arne (or equivalent) - and nothing else except robustness. This also is the area where the mast needs to be at its strongest in regard to bending.

    Sometimes people have had to carefully work around a situation where holes have already been drilled in a mast tube, but you would want to think long and hard before doing it on purpose. Bolts or welds are not a "100% solution" where no fitting is called for - of all places, especially at the partners. At best they will add nothing to a mast which is already held in place perfectly well at the heel - and at worst are a quite possible cause of failure.

    With a little boat like Karl's things are a bit less critical and that sort of creativity is probably OK - but it seems to me that what you have been considering for your Contessa is the result of over-thinking and imagining too much, while ignoring an existing well-proven body of thought. 

    A Contessa with a split junk rig sounds like an exciting combination and I sure wish you were here ("down under") so we could see a match race with Zane's Pango (which sails beautifully). Your project is of great interest - best wishes and keep us informed.

    Last modified: 31 Oct 2020 05:08 | Anonymous member (Administrator)
  • 30 Oct 2020 23:44
    Reply # 9336618 on 9327660

    Ueli!

    Thanks for the heads up. Took a little searching around but I was able to find a slightly thicker pole. So now I am looking at one 8 in diameter with a wall thickness of 7/32" or .219" or 5.56mm. this would not quite get me 3x over my righting moment, but definitely closer. I got ahold of the manufacturer, and unfortunately they don't offer any weights on the product. Just a guess, but I would say that this is going to put me over 150lbs of mast. Is this of any concern??? 


    Karl!

    I agree with your 100 % aproch. I plan on doing some rolling around and it would be really nice to see the mast still attached at the end of it all. That cuff sounds perfect. Where ya find something like that? Is it like a hose clamp?


    David!

    I would like to get away without drilling any wholes into the mast if possible. Do you think I could get away with just a mast collar? I could have my friend Tig on some wings to bolt down the mast but then I have no options to removing it. Is through-bolting it the way to go? I feel like the weld's might weekend the mass more than the bolt  holes??? Ether way, I'll keep the connection as close to the heal as possible.


    Zane!

    I have an email for you that failed to send. Turns out there is something wrong with my e mail. I'll send it via my work email... I thought that you had a carben fiber mast! Watching that thing whip and bend as awesome! Looks fast! If you can find the yield stranth of the material the mast is made of you can plug it into Arnie's formula. I got the max righting moment of the contessa 26 at 1306KpM (this is my best guess)

  • 30 Oct 2020 11:43
    Reply # 9335350 on 9335195
    Karl wrote:

    Hi Jeffrey,

    On the the ocean you should go 100 percent sure by drilling a number 8 hole through the mast and insert a SS threaded bar sticking out 2 cm on each side locked with 2 nuts directly under the partner so the weight of the mast cannot gain momentum when falling towards the ocean bottom in case of turtle. If it is only 2 or 3 cm ( appr. 1 inch ) below the partner it also stays nicely in the 15 cm deep foot. Greetings from Karl


    Sorry, Karl, but I have to say that this is absolutely the most ill-advised thing to do!!! Never, ever, make holes in an aluminium mast near deck level. A hole at the most heavily stressed area of the mast leads to premature fatigue cracking and the loss of the mast. Not just a theory, it has happened.

    Holes near the heel don't cause the same problem, so by all means tie down the mast to the mast step with brackets and screws, or something similar.

  • 30 Oct 2020 09:47
    Reply # 9335256 on 9327660

    I too have a Contessa 26

    Mast is carbon fibre, 9.3m length, 135mm ID , with a 4.7mm wall.

    I guess I could measure the OD as the mast is currently out of the boat stored at the house.

    I wonder where my mast sits in the scheme of things compared to what is being discussed here for the same model boat.  



  • 30 Oct 2020 08:27
    Reply # 9335195 on 9327660

    Hi Jeffrey,

    My strap on collar just below the mast partner is made of 2 strong half shells aluminium and like traffic signs attached to their pole have 2 screws and nuts on opposite sides which pinches the mast very hard and my 6 kg mast would stay put in case of a rollover for sure.

    On the the ocean you should go 100 percent sure by drilling a number 8 hole through the mast and insert a SS threaded bar sticking out 2 cm on each side locked with 2 nuts directly under the partner so the weight of the mast cannot gain momentum when falling towards the ocean bottom in case of turtle. If it is only 2 or 3 cm ( appr. 1 inch ) below the partner it also stays nicely in the 15 cm deep foot. Greetings from Karl


  • 30 Oct 2020 04:19
    Reply # 9335010 on 9327660

    hi jeffrey

    i meant, i would like to have it a bit stronger than your 8"-5/32" pole with a safety factor of two times the righting moment.
    feel free to go for factor two. but i'm almost sure i would have lost a (bermudan) rigg in really rough conditions the northern atlantic ocean with this factor.

    for a 'go everywhere boat' i would search for something near three times the righting moment – but i may be a bit conservative in such things…

    ueli


    Last modified: 30 Oct 2020 04:20 | Anonymous member
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