Foremast rake and sheeting angle

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  • 18 Nov 2014 18:38
    Reply # 3153644 on 3143435
    Deleted user
    That's it! I'm going to build a raised patio, complete with BBQ, palm trees and a hammock, overhanging the stern of my boat! Problem solved!! - So it sounds like if there is more mast windage aft than forward it isn't an issue. Shipping and unshipping a mast at anchor doesn't sound like much fun unless it was carbon fiber or a very small mast.
  • 18 Nov 2014 12:18
    Reply # 3153371 on 3143435
    Deleted user

    'In the literature' concerning traditional junks mention is often made of just that effect - that the high sterns of junks caused them to lie much more quietly into the wind - both at anchor, and when lying 'a-hull' in adverse weather.

  • 18 Nov 2014 10:35
    Reply # 3153336 on 3143435
    Anonymous member (Administrator)

    Ancoring with a mast at the bow

    I haven’t got that much experience with anchoring with a sloop JR, but my first junk, the 7.1m/23' Malena, at least, tacked about badly when anchored from the bow, so I later anchored from the stern (protected water, no current). It is at such occasions I wish I had a yawl.

    Still, I have (safely positioned in my armchair) wondered if one or two methods could be helpful when anchoring from the bow:

    Offset anchoring
    As this diagram shows, a second line is attached to the anchor rope (or chain). By cleating it from a point at the cockpit, one can adjust the offset angle just enough to prevent the boat from going about. Remember, the anchor chain and this second line form a bridle, which in effect extends the bow. The shown offset angle is probably (hopefully) wider than what is needed to tame the boat.

    Bucket or drogue
    Another armchair idea is to tie a big bucket or drogue to the anchor chain and let it sit just below the water surface. On small and light boats, this could possibly stop the boat from yawing about. 

    I bet the Chinese, those who had the forward positioned centre-board, dropped it and raised the rudder to get the same weather-cock effect. Could it be that their tall sterns also were built to help weather-cocking when at anchor and when sitting hove-to?



    Last modified: 18 Nov 2014 14:10 | Anonymous member (Administrator)
  • 17 Nov 2014 19:31
    Reply # 3152917 on 3151934
    Ben wrote:Is it the raked foremast that contributes to the boat searching at anchor, or just any mast in the bow of the boat?
    It's just the windage up forward.  Cutters with two roller-furling headsails have the same problem.  Being able to lower that foremast would be a huge relief when anchored in hurricane-force winds.  Particularly hurricane-force gusty winds.  If you had three masts, you'd get a doubling of advantage, because you would now have the windage of the mizzen helping to keep you head to wind.  On the other hand, lowering a big mast, even at anchor, if you're single-handed, could be very, very interesting.  One of the reasons why Small is Beautiful!
  • 15 Nov 2014 21:34
    Reply # 3152033 on 3143435
    My thoughts too Ben. Schooners and 1 masters have slightly raked masts at or near the bow. It probably has a lot to do with hull shape, displacement and type of keel. Shoestring is shoal draft, so the long keel might help it stay settled.
  • 15 Nov 2014 15:00
    Reply # 3151934 on 3143435
    Deleted user
    Is it the raked foremast that contributes to the boat searching at anchor, or just any mast in the bow of the boat?
  • 15 Nov 2014 14:20
    Reply # 3151925 on 3143435
    Deleted user

    Back on the boat again, starting the metalwork, beginning with the mainmast tabernacle. When I get to the foremast, will arrange things so I can lower it as easily as possible, crowded, windy anchorages are unavoidable sometimes and a boat that's squirrelly on the anchor can be a very bad thing. The foremast is fairly big but not too heavy, should be able to manage raising and lowering it.

    I've ruled out using the foremast for MOB, thanks for pointing out the fuzzy logic in that idea. Wandering off topic here, but anyone know of a good design for a sturdy davit that wouldn't interfere with my mainsheets, or anything else?

  • 15 Nov 2014 04:46
    Reply # 3151821 on 3143435

    Re the sheeting: My battens are all the same length, but a fan shape. With a raked mast, the higher the sail is on the mast, the more space you have for sheeting. That's another reason I wanted to extend the mast.

    I copied some photos of traditional junks and hung the foresail so the leech was nearly vertical. It means the boom is almost balanced on the mast. I think that is what makes it  so light and responsive. It also means that the sheeting is at a better angle and shouldn't catch on the battens when gybing or tacking.

    If your main mast is too far forward, you'll probably have to try double sheeting.

    I drew a scale plan of the boat and masts on a sheet of A3 and cut out scaled paper sails. I moved them up and down the mast and changed the angles of the sails to see what fitted best and how much sail area I could get.

  • 15 Nov 2014 03:18
    Reply # 3151805 on 3143435

    Hi Ben,

    Yes, I if I keep my main mast in the same position, I would love to try the taller rig with mizzen and foresail. Ideally I'd make the smaller masts out of lighter material so they can be lifted out. I want to play around and see what works best.

    Also thinking of shifting the main mast forward by a metre and using a tabernacle. If that is the case I'll probably have an off set mizzen sail. That's the beauty of Carbon Fibre. It is light enough to move without major upheaval, just so darn pricey!

  • 14 Nov 2014 21:35
    Reply # 3151697 on 3143435
    Deleted user

    I must be missing something in my drawings.

    The forward rake of the foremast along with the decreasing batten length appears to provide less angle for the sheets and hence, more clearance of the mainsail.

    If  I draw a foresail with battens of the same length, sail area of nearly the same amount, and little or no mast rake then the sheeting angle increases to near vertical and crowds the mainsail.

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