Pete Posted December 19, 2011 Report Share Posted December 19, 2011 My mast base and mast step have both been cut away giving me a heap of mast rotation. Even with my heavy bodyweight the boat flies downwind but is not so good upwind. Back in the day (late 70s/early 80s) we would cut the mast base so that the mast would approximately line-up with the side stay. Currently my mast lines up well forward of the side stay. I am using a full-cut Cairns sail. How much mast rotation are the good guys using these days? I am guessing the light guys would be using a lot more than the heavier sailors. Link to comment Share on other sites More sharing options...
Dr Peter Posted December 22, 2011 Report Share Posted December 22, 2011 mast rotation I did the same to mine and the way to adjust the amount of mast rotation is to play with the positioning of the mainsheet on the boom. I found the downhaul to be pretty useless afterwards as mainsheet tension tended to pull the boom down the mast track too. The vang is still handy for down wind work. Peter Link to comment Share on other sites More sharing options...
knobblyoldjimbo Posted December 22, 2011 Report Share Posted December 22, 2011 If your sail is full then you'd possibly want to flatten it uphill by i) using the downhaul and ii) getting mast bend with the mainsheet. Having the step cut away will assist this. If the sail is oldish then consider that the bolt rope often hardens and tightens over time. On my very old racing sail a sailmaker released the rope from the clew, trimmed the rope and then inserted a new piece about 6" long and tacked that back into the bottom. Result is that the old rope can move freely in the sleeve and I have good downward tension on the downhaul. On my last boat I had a very nice Eastwind main (cracked like a rifle and smooth as a baby's bum!) which was relatively flat - actually pulling it up put bend in the mast and pulling the downhaul down put more bend in the mast. Link to comment Share on other sites More sharing options...
korwich Posted December 25, 2011 Report Share Posted December 25, 2011 Jimbo Dr Pete has removed all of the stop from the bottom of his mast step, so can get infinite rotation,(in theory), he could even get the mast to have the sail track facing the bows if he was strong enough, (must be a secret Victorian method of winning the nationals in cat rigged) Link to comment Share on other sites More sharing options...
darcy1945 Posted December 27, 2011 Report Share Posted December 27, 2011 At 95/97 kg I do not have any increased mast rotation from original, and I can still manage to de power in strong conditions with downhaul (6 to 1) and main sheet. I believe that extra rotation is only for lightweights, 80 kg or less. Some of the early mast sections (still available?) were much stiffer with 4 vertical internal ribs, (take mast cap or base off to check, I have only found 1 in a dozen or so masts) these masts would require extra rotation to assist in mast bend. The ribbed masts may also have been used in Hydra masts (same section but longer). Link to comment Share on other sites More sharing options...
humungus2 Posted December 28, 2011 Report Share Posted December 28, 2011 I am not a light weight. I have a lot of mast rotation. It is not all about the de-powering. It is also about wind flow around the mast and on to the sail. There is a big difference I find in the taking of from a standing start. I personly feel you have a quicker take of because of better air flow, Link to comment Share on other sites More sharing options...
Pete Posted December 29, 2011 Author Report Share Posted December 29, 2011 Mike - how much rotation are you using? I use a system of 2 bolts and washers through the mast step to adjust the amount of rotation. I am just trying to get a ball-park idea of what is fast. My race sail is only 5 races old, and my mast is a 1981 original lightweight with no internal bracing. Sadly I am now the only Maricat left at my club - Paper Tigers have taken over. The standard is pretty high. Thank you for your comments. Much appreciated from the southern most racing maricat. Link to comment Share on other sites More sharing options...
knobblyoldjimbo Posted December 30, 2011 Report Share Posted December 30, 2011 at manno there are a couple of PT's and we can often keep up with them, they usually grumble about the Mari having 25% more sail area! I'd start with what one guy said here, rotate to the shrouds and see how that works. Next time I see Mick I'll have a sneaky peak at how much rotation he has. I've just cut a bit back from my step - I think that the lack of rotation was flattening the sail although more rotation logically means that you get the mast sideways and thus can get it bending to flatten the sail. I often think about the DN ice yachts, they bend their masts to leeward to flatten their sails, I guess we just don't go fast enough for that! Link to comment Share on other sites More sharing options...
humungus2 Posted December 30, 2011 Report Share Posted December 30, 2011 I have posted 2 photos of my rotation specs before cut out. go to the Maricat association face book page. Go to facebook then type in Maricat association NSW ACT Link to comment Share on other sites More sharing options...
korwich Posted January 1, 2012 Report Share Posted January 1, 2012 Mick Pirate Scotty and me all have about the same amount of rotation. Essentially we remove enough of the mast step rotation stops so as the mast sail track is pointing directly at the side stay. There are a number of ways to remove the stops, one way is to drill series of holes where you want the cutout, then join the drill holes with an old wood chisel, bit by bit, clean up with a file and the chisel. Or you can use what I used, a die grinder fitted with an aluminium appropriate rotatary burr, its fairly quick but easy to overdo it if you are'nt carefull. Oh and I'm using trap, super sloop, and this amount of rotation seems OK to me. Phil Link to comment Share on other sites More sharing options...
Scuttlebutt Posted January 1, 2012 Report Share Posted January 1, 2012 I would point out that Donna won the Nat a couple of years ago and has a bog standard mast base with no cut outs. Maybe the advantage is all in your head??? Link to comment Share on other sites More sharing options...
Pointed Reply Posted January 2, 2012 Report Share Posted January 2, 2012 I have been really struggling with the new foam boat and radial sail for the last year. Way over powered in anything over a gentle breeze. Yes Mick/Phil I know I am only light ! I have been gradually filing away at the mast step and stopper. It is now such that the mast will point in front of the side stays, which allows the sail to be flattened. While I am not at the front of the fleet, I am getting closer and at least I can control the boat. The old glass Pointed Reply (in which Zac and I beat every Maricat afloat) was also set up like this. So I don't think it is just in my head. Also lots of downhaul and outhaul. Link to comment Share on other sites More sharing options...
knobblyoldjimbo Posted January 2, 2012 Report Share Posted January 2, 2012 http://catsailor.net/forums/album.php?albumid=9&attachmentid=259 Rodney, afraid you'll have to invest in an Eastwind sail - if you can see the attachment pic - Dave made three, one for me, one for Brenton and one for Darcy. Brenton tried Darcy's the other day and liked it much more than his, mine (#37) is flatter and if I was able to sail properly would do well with it. I'm sure that Dave has the exact dimensions of all three sails (Dave doesn't do random, cut here and see what it shapes up to be!) The nice things about it is that it's cross cut so few seams and made with a dacron that is smooth as a baby's bum and cracks like a rifle. When up, it put bend into the mast and with a heave on the downhaul would bend the mast more and flatten it up but also would let the top third fall off slightly. Me, I got too scared when hit with gusts so tended to flatten the sail too much with the downhaul which then made it harder to tack. I sold #37 sadly so am still trying. Link to comment Share on other sites More sharing options...
knobblyoldjimbo Posted January 3, 2012 Report Share Posted January 3, 2012 Rodney, sorry - should have told the truth - its the boat, get rid the POS - clearly not up to scratch - keep the sail. Tell you what, I'll swap - how about - ooh $500 plus my boat but you can keep the sail. Link to comment Share on other sites More sharing options...
Pete Posted January 7, 2012 Author Report Share Posted January 7, 2012 Thanks for the comments. This forum is brilliant for those of us living out in the sticks. I think I will go back to limiting the rotation so that the mast is in line with the side stays. Link to comment Share on other sites More sharing options...
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