Unsteppjng Mast on 37c
- Thread starter BayMan
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Mark your stay adjustments before you disassemble....you will be glad that you did when you reassemble. Have fun!
I'm not sure it matters that much about marking things, you might want to find a cable-tension gauge, I think they're called a loudge gauge. That'll allow you to keep each side equally tight. Use a steel 50 foot tape measure to center the mast against the toe rail measuring at various points along the toe rail. Take measurements on port and starboard at equal intervals coming back along the toe rail. But that's all about putting it back. You might want to look at where your mast goes thru the cabin top. I have a 81 37C too, and after carefull analysis, I need to move my mast about 1/2 inch forward (I think, it's been a while since I've looked at it) and to move it forward, you have to move the mast step. My mast step is already slid as far forward as it could go and to do it right, I'm going to have to have a new one made. That should be pretty easy for most any machine shop. But besides that, inspect things as you go, hopefully everything will pull apart without too much force. I've had my mast out three times over the past 9+ yrs, and it's about time to do it again. This time, it won't be to move the boat, but actually work on it; new sheaves, step, paint, and lights. PS, I'm going back to incandescent bulbs, less likely to blow if lightening surge, cheaper too.
The other advice that's helped me is pictures of wiring blocks, putting pieces of 3m blue tape on things to mark what's what, have a small parts bucket ready (don't put parts here and there in piles, they'll disappear), and of course get input from as many as you can stand, make your choices and go... and welcome to the club. Next time you see a couple three guys take down a keel stepped mast out of a J24 while motoring back to the dock using a Gen-pole, yea, it makes it look easy. Oh, one last thing, I found that on the 37C specifically, make sure you pull the bolts going thru the mast at the cabin top outside, and down at the step ( yea, I bent one pulling the mast before she was free) and I took the settee cushions out and built a thing up using boxes and pieces of wood to hold the table up nice and high and out of the way. You'll probably have to dive down there to unhook some unforseen thing. The table will want to walk all over the place as the bottom of the mast is being pulled up, I had one guy outside and I was down below guiding the table up holding onto the table and pushing wires up after the base cleared the cabin top. After that, the crane operator should be able to set it down and the work begins. I hope you take pics and relay your experiences.
Thanks,
Kb
s/v Renasci
The other advice that's helped me is pictures of wiring blocks, putting pieces of 3m blue tape on things to mark what's what, have a small parts bucket ready (don't put parts here and there in piles, they'll disappear), and of course get input from as many as you can stand, make your choices and go... and welcome to the club. Next time you see a couple three guys take down a keel stepped mast out of a J24 while motoring back to the dock using a Gen-pole, yea, it makes it look easy. Oh, one last thing, I found that on the 37C specifically, make sure you pull the bolts going thru the mast at the cabin top outside, and down at the step ( yea, I bent one pulling the mast before she was free) and I took the settee cushions out and built a thing up using boxes and pieces of wood to hold the table up nice and high and out of the way. You'll probably have to dive down there to unhook some unforseen thing. The table will want to walk all over the place as the bottom of the mast is being pulled up, I had one guy outside and I was down below guiding the table up holding onto the table and pushing wires up after the base cleared the cabin top. After that, the crane operator should be able to set it down and the work begins. I hope you take pics and relay your experiences.
Thanks,
Kb
s/v Renasci
- Dec 30, 2009
- 680
If its deck stepped MARK THE STAYS, you will be glad u did. Its a good stsrting point even if you choose to re-tune. If it keel stepped mark where its landed, and take note of the shims at the deck pass thru, you may want to mark location, and mark them with letters or numbers, like on a clock face. Spring is a long way off, you will be glad, oh yea I second, take a bunch of pictures...Red
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Sail what you are referring to is a Loos Gauge. It will be needed after the mast is stepped to adjust the stays. There are three sizes and one you will require is dependent on the size of your stay. Adjusting the tension is the final step and one will be needed to complete the process.
This must be the year for H37C masts - I am planning on unstepping mine as well. I have always found it useful to measure and record the distance between the top and bottom clevis pins on each turnbuckle. Its always easy to get back close to your previous tuning using these measurements (provided you don't move the mast step, change stays, or otherwise modify the rig). Loos gauge or "plucking the strings" is for fine tuning, once everything is straight and even.
In addition to marking I also take a picture of each turnbuckle (all three shrouds terminate on a single chainplate on each side of my boat, so it's only a few pictures). The resolution is good enough on my SGS2 phone that i can blow the images up enough to count threads if needed.
I also needed a ladder on deck to position the lifting strap between the upper and lower spreaders (B&R diamond rig). I don't know if you'd have to do the same or if you can position the lifting strap from the deck or otherwise (likely not an issue if you have a single set of spreaders).
I also needed a ladder on deck to position the lifting strap between the upper and lower spreaders (B&R diamond rig). I don't know if you'd have to do the same or if you can position the lifting strap from the deck or otherwise (likely not an issue if you have a single set of spreaders).
I personally think you guys are wasting your time marking anything. Once you pull the mast, the hull is going to move so much it will take months for it to regain its old set. You will be constantly retuning untill this happens. It was more of a concern for me sisce I race my boat, but it is still a concern. If you pull the mast while the boat is out of the water it will move more. Plan on doing a crap load of corrosion control on the step and base of the mast. If you don't put the pin (bolt) thru the mast at the partners first when re-rigging it, you never will.
I was lucky enough to have a couple of the top factory guys from Tartan/C&C show me how to tune a mast. We did it out of the water, if you're not, you can't incorporate any keel offset, but you can still get it centered via the deck to hull seam. Oh yea, all of this negates having to mark anything, because you'll be putting the mast right where it needs to be, and this applies only to the H37C, which does not have a deck stepped mast. First, measure the same point on the bottom of the keel to different spots on the toe rail, and see where it lies. If it's centered, yea haw. If not, note which direction and how much. You'll want to have the top of the mast off set by the same amount and towards the same side that the keel is favored. Then, use a steel tape measure and center the mast from side to side, tightening the shrouds one at a time, a little at a time. The two lower inner shrouds can be tweeked a turn or two this way and that, to help pull any unwanted twisting. You'll want a straight mast with no rake backwards like a racer, or sideways lean. Then put your backstay and headstay on with about the same tension as the outter shrouds, you'll find tune them later. Both forward stays and the backstay should be tighted so that again, there's no twisting fore, aft, or sideways. Its easy to pull a bow into it with the staysail stay, I tweek the aft inner shrouds slightly tigher than the forward inner shrounds. The turnbuckles should end up pretty close to where you had them before. Now, you can do a final tweek once you're out sailing. If you have weather helm, move the top of the mast forward, if you have reverse weather helm, move it back. When 10 - 13 knots of breeze and the stay sail, jib, and main all out and properly trimmed, the helm should stay steady and shouldn't need a brake on it to hold it down, and the boat shouldn't try and round up. This initial sail is a good time to also see if the outter shrouds need another turn taken and made a little tighter. On the above mentioned sail, on a beat headed to wind, the leeward shroud should be fairly loose and the cable could swing 4 to 8 inches and be properly adjusted. Things stretch more than people realize and if you tighten the shround so there's nothing is ever swinging, then it's way to tight and you'll start the 'banana' the boat. You'll know when the swinging door to the head doesn't work anymore and the bulkheads get pushed out of their seats. The check stays only stablize the mast and stop it from pumping, so don't look at them as running backs that'll put power into a mainsail. Most importantly, don't skip proper retaining rings/mechanisms for the turn buckles as they're going to dangle loosely on the lee side, and wrap them so they don't bite feet and toes. Now, to the mast step. If there is just a tiny tiny little bit of weather helm (which is considered perfect) and the mast goes thru the deck okay, then you're set, if not, then move the mast step so things clear, then you might have to recheck and move the top of the mast again if the weather helm adjustment is lost, more than likely not. Then, because the H37C doesn't use shims, the collar on the cabin top is positioned/bolted and you should be done at that point.
But that's adjusting the mast. Since I last posted, I also thought to tell you to replace any questionable lights, you don't want to cause any more electrolysis than what's going to happen already. Yea, I had dimples in the bottom inside of the mast, I almost cut a couple of inches off, maybe next time.
Have fun,
Kb
s/v Renasci
But that's adjusting the mast. Since I last posted, I also thought to tell you to replace any questionable lights, you don't want to cause any more electrolysis than what's going to happen already. Yea, I had dimples in the bottom inside of the mast, I almost cut a couple of inches off, maybe next time.
Have fun,
Kb
s/v Renasci
Oh, and I knew I'd forget about how to adjust the tension on the forestays and backstay. On a similar type sail, when going downwind, the forestay shouldn't get loose like the lee side shrouds are supposed to be. You can tell the fore stay is tight enough because with the yankee cut jib, it should cause the fore stay to sag to lee by about 4 to 6 to maybe 8 inches in the very middle. If the fore stay stays straight when under sail and when looking from the bottom of the stay looking up to the top, then it's way to tight. It should sag some. The staysail stay can then have it's final adjustment, it should only have a little sag, less than the forestay, and the mast shouldn't bulge forward or aft at the point where the stay attaches to the mast.
I've had things way too loose where they where swinging wildly, and I've had things so tight that the doors didn't work and I bet it was a few inches shorter. I've also had fun tweeking the turn buckles a turn at a time, doing a pair at a time, trying to get the cables inside to not bang while sitting at the dock. Yea, when it blows somewhere around 14 to 18 at a slightly greater angle then head on, the mast pumps back and forth and the cables inside the chaseway rattle back and forth. The pumping action is only about a 64th of an inch if that much, but the cables rattle and the sound is magnifyed down below. I happens only very rarely now and I guess I'm going to have to pull is sooner than later. I'd give you the numbers off what my gauge says, but I would want to garuntee that they're wrong if compared to another machine. I use my gauge to check one against the other and get the tension the same, whatever the actual numbers are. Even then, I have to do small adjustments afterwards of course.
Happy sailing,
Kb
I've had things way too loose where they where swinging wildly, and I've had things so tight that the doors didn't work and I bet it was a few inches shorter. I've also had fun tweeking the turn buckles a turn at a time, doing a pair at a time, trying to get the cables inside to not bang while sitting at the dock. Yea, when it blows somewhere around 14 to 18 at a slightly greater angle then head on, the mast pumps back and forth and the cables inside the chaseway rattle back and forth. The pumping action is only about a 64th of an inch if that much, but the cables rattle and the sound is magnifyed down below. I happens only very rarely now and I guess I'm going to have to pull is sooner than later. I'd give you the numbers off what my gauge says, but I would want to garuntee that they're wrong if compared to another machine. I use my gauge to check one against the other and get the tension the same, whatever the actual numbers are. Even then, I have to do small adjustments afterwards of course.
Happy sailing,
Kb
You say:
"Then, use a steel tape measure and center the mast from side to side, tightening the shrouds one at a time, a little at a time"
Measuring from where to where? The higher up the mast the more accurate but how high is necessary ?
Wow. A lot of info. This is going to be a project.
"Then, use a steel tape measure and center the mast from side to side, tightening the shrouds one at a time, a little at a time"
Measuring from where to where? The higher up the mast the more accurate but how high is necessary ?
Wow. A lot of info. This is going to be a project.
I can't find fault with anything written here, but some folks put a lot more thought and effort into tuning their rigs than I do - I'm sure it rewards Blaise and SailH37 with a few more 1/10 of a knot boatspeed too! I could never keep up with them anyway with my 20 yr old sails...I tend to take an organic approach to tuning: I start by trying to get the mast straight side-to-side using a long tape measure hoisted to the top on a halyard and checked at the chainplates; my fore and aft is largely a matter of getting enough tension on the forestay (the bolt at the partners precludes much change anyway). After that I spend most of the summer just tweaking things. Every time I am out in heavier winds, I sight up the mast for bends, falling off on top, etc. and adjust things as necessary, always matching the # of turns on the turnbuckles port & starboard - this can mean "+/+" or "+/-" a turn on each side. Sometimes it takes a while, but my tuning is usually pretty good by mid season. I don't worry too much about how symetrical the keel, partners, chainpates, maststep, etc. are - that's just who she is (one of my ears is higher than the other and my nose isn't straight either!). Works for me.
Hey, thanks for asking, I should have tried to be more specific, but I'm always fighting the dreaded verbose monster. When centering the mast, yea, run the tape measure all the way up to the top, tie the end to a halyard. That way it's very acruate as the steel won't stretch like a halyard will. As far as where to on the other end, it works well to measure the toe rail coming back from the anchor up front, and make a mark perpendicular to the mast (right in line with the spreaders) then mark every couple of feet for about, say, ten feet. There's a point where you loose acuracy the further back you go, and you can measure to the toe rail going forward, but the tape ends up wrapping around the mast and it looses acruacy. You can re-launch the tape with a spin halyard and measure to the toe rail forward of the spreaders, but it's kinda redundant. When I start out, everything is hand tight, then I put on about 1/4 full tension on one upper shroud, then put on 1/4 tension on other, which adds up to half of full. Then I hand tighten the forward and aft lower shrouds watching the twisting in the mast. Which, looking for twist is easy once someone shows you, place your head next to the mast looking up and close the outside eye, using the one right next to the mast. Looks from the side to see forward and aft twists, look from forward and aft to see twists along that axis.
Also, to answer what I was talking about with moving the mast forward and aft, all this does is control weatherhelm. It is sometimes a trick to get the weatherhelm just right and end up with a forestay that is as tight as needed. As far as I know, there's no real tuning with the backstay, unless you're adjusting it while underway with block n tackle or hydrolics. If you've got that type of rig, then it kinda negates tuning the forestay. But, back to moving the mast. If you move your keel step all the way forward, and adjust your headstay turnbuckle all the way tight and have only minimun on the backstay turnbuckle, then you should have reverse weatherhelm. This means that when beating to wind, the helm will want to constantly turn so that the bow ends up going down wind. Moving the mast all the way back, will cause weatherhelm which is what we want, but probably too much which would cause the boat to want to constantly round up and tack. This is an incredibly slow thing, to have the rudder being dragged thru the water sideways. Somewhere in the middle is what is needed, so that the helm is mostly neutral, just a slight bit of weatherhelm. I find that the perfect amount for me on the H37C, is (and I can do this now because most everything is new in the steering department whereas if you have friction and the wheel doesn't turn freely, it'll be tougher ) is to have everything trimmed and set, then let go of the wheel, and it should track straight for at least a couple of 4 to 6 waves, depending on the conditions of course. You can really feel the weatherhelm and reverse-weatherhelm really well with a tiller boat. All the aqua engineers say that it's best to have just a tiny bit of weatherhelm because it helps with forces being applied and involved with the keel and the other aero/aqua dynamics. Backtracking here a second, the other thing to of course thing of when moving the mast fore and aft, is getting it to fit thru the cabin top and not bang against the inside of the hole wallering things out. Without the collar that we have, there's shims and rubber collars, but for ours, I'm still engineering what I think will work well. I'm open on ideas. I've used one of those rubber/plastic stair step collars and slid that one prior to stepping the mast. Some say, you can't stop the rain from coming down so feel comfortable having it minimalized, and I can see this with driving rain being forced into the top and at other openings. But, I know that with our collar, with everything being bolted well, it not only strengthens the mast, but the cabin top as well. There's old blogs of the first h37c's having problems with the top oil-canning.
Well, I think the verbose monster hit again, hope this helps,
Kb
s/v Renasci
Also, to answer what I was talking about with moving the mast forward and aft, all this does is control weatherhelm. It is sometimes a trick to get the weatherhelm just right and end up with a forestay that is as tight as needed. As far as I know, there's no real tuning with the backstay, unless you're adjusting it while underway with block n tackle or hydrolics. If you've got that type of rig, then it kinda negates tuning the forestay. But, back to moving the mast. If you move your keel step all the way forward, and adjust your headstay turnbuckle all the way tight and have only minimun on the backstay turnbuckle, then you should have reverse weatherhelm. This means that when beating to wind, the helm will want to constantly turn so that the bow ends up going down wind. Moving the mast all the way back, will cause weatherhelm which is what we want, but probably too much which would cause the boat to want to constantly round up and tack. This is an incredibly slow thing, to have the rudder being dragged thru the water sideways. Somewhere in the middle is what is needed, so that the helm is mostly neutral, just a slight bit of weatherhelm. I find that the perfect amount for me on the H37C, is (and I can do this now because most everything is new in the steering department whereas if you have friction and the wheel doesn't turn freely, it'll be tougher ) is to have everything trimmed and set, then let go of the wheel, and it should track straight for at least a couple of 4 to 6 waves, depending on the conditions of course. You can really feel the weatherhelm and reverse-weatherhelm really well with a tiller boat. All the aqua engineers say that it's best to have just a tiny bit of weatherhelm because it helps with forces being applied and involved with the keel and the other aero/aqua dynamics. Backtracking here a second, the other thing to of course thing of when moving the mast fore and aft, is getting it to fit thru the cabin top and not bang against the inside of the hole wallering things out. Without the collar that we have, there's shims and rubber collars, but for ours, I'm still engineering what I think will work well. I'm open on ideas. I've used one of those rubber/plastic stair step collars and slid that one prior to stepping the mast. Some say, you can't stop the rain from coming down so feel comfortable having it minimalized, and I can see this with driving rain being forced into the top and at other openings. But, I know that with our collar, with everything being bolted well, it not only strengthens the mast, but the cabin top as well. There's old blogs of the first h37c's having problems with the top oil-canning.
Well, I think the verbose monster hit again, hope this helps,
Kb
s/v Renasci
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