mast base adjustment on 33
Moderator: Jim Walsh
mast base adjustment on 33
I have a 1981 CD 33 and the mast is raked aft but it is also set against the forward portion of the mast opening in the salon roof. Is the base, where the mast meets the keel, adjustable somehow? I need to move the mast base aft in order to straighten out the mast.
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mahalocd36
- Posts: 591
- Joined: Feb 5th, '05, 10:51
- Location: 1990 CD36 Mahalo #163
- Contact:
Rigging tension....
Before you go to drastic measures, you might want to try moving it by adjusting the tension on the stays. I doubt CD messed up so badly as to put the mast step in the wrong place on the keel.
Cape Dories are not meant to have a large rake in the mast.
On our 36, one could get the result you have by overtightening the backstay, and maybe uppers, and not having the proper shims around the mast in the opening in the roof.
Are there shims around the mast? Ours are just wedges of wood (originally pine, now teak) but there should be something there.
First, get back to "ground zero" and loosen all the stays significantly. Then align the mast in the hole, and put shims all around it. If you have a pin that goes through the collar, insert it. Then tighten the rigging as described on many other threads on the board. Do one side, then the other, a little bit at a time, always sighting up the mast to ensure it's straight fore/aft and side to side and doesn't have any funky bends in it. We work our way "up" doing lowers, intermediates, then the top.
A rigger's gauge is helpful to ensure you don't have anything too tight.
Cape Dories are not meant to have a large rake in the mast.
On our 36, one could get the result you have by overtightening the backstay, and maybe uppers, and not having the proper shims around the mast in the opening in the roof.
Are there shims around the mast? Ours are just wedges of wood (originally pine, now teak) but there should be something there.
First, get back to "ground zero" and loosen all the stays significantly. Then align the mast in the hole, and put shims all around it. If you have a pin that goes through the collar, insert it. Then tighten the rigging as described on many other threads on the board. Do one side, then the other, a little bit at a time, always sighting up the mast to ensure it's straight fore/aft and side to side and doesn't have any funky bends in it. We work our way "up" doing lowers, intermediates, then the top.
A rigger's gauge is helpful to ensure you don't have anything too tight.
Melissa Abato
www.sailmahalo.com
www.sailmahalo.com
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s.v. LaVida
- Posts: 310
- Joined: Feb 9th, '05, 07:10
- Location: LaVida is a Cape Dory 33, Hull#40 Homeport of Olcott,NY
33 rake
I agree, you need to readjust your standing rigging first.
Unless the PM relocated something or has done something crazy, everything should line up.
Mike
CD33
LaVida
Unless the PM relocated something or has done something crazy, everything should line up.
Mike
CD33
LaVida
How much rake?
The amount of rake on your mast can be determined easily providing your boat sits on her designed waterline. You'll have to remove all the tension from all shrouds and stays and remove the boom from the mast. See how far the main halyard hangs behind the mast when measured on a calm day. If you have a lot of weather helm, maybe the halyard will be too far back, say 10-12 inches. If so, you can adjust the mast step and get the mast in column again so that the halyard hangs maybe 2-4 inches aft of the mast. If the halyard isn't long enough to almost reach the deck, attach some type of plumb bob so that it does. Sailing will test the adjustment.
It's not rocket science to move the mast aft at the mast step. There are 4 nuts that may be loosened (after all tension has been removed from the shrouds). But there is a 6-fold magnification of masthead displacement for each unit of adjustment at the step. If you move the mast base 1/2 inch aft, the top of the mast will move about 3 inches forward assuming the mast at the collar is tightly fixed.
If you sense too much weather helm, try a small adjustment and measure the effect. Remember, a small amount of weather helm is desireable.
It's not rocket science to move the mast aft at the mast step. There are 4 nuts that may be loosened (after all tension has been removed from the shrouds). But there is a 6-fold magnification of masthead displacement for each unit of adjustment at the step. If you move the mast base 1/2 inch aft, the top of the mast will move about 3 inches forward assuming the mast at the collar is tightly fixed.
If you sense too much weather helm, try a small adjustment and measure the effect. Remember, a small amount of weather helm is desireable.
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Leonard Lookner
- Posts: 74
- Joined: Mar 17th, '05, 07:54
- Location: Cape Dory 36 mariposa hull #3 Camden Maine
mast rake
To be honest I know very little about tuning a rig, however I am surprised that the mast partners were not mentioned as part of the solution. With the heft of a cape dory mast it would probably pull up the chain plate before you could create any significant rake.
Angled, not bent
Thanks for all the replys. The mast is not bent aft, but rather angled aft. As the mast is all the way forward in the opening in the coach roof and still angling aft, adjusting the shrouds will not solve the problem. If I set the mast in the middle of the coach opening, the mast would be angled aft even more.
What are mast partners? There are some wedges around the mast but I gathers this is not the same as partners.
Actually I have not had a chance to actually sail the boat yet. She is an insurance salvage (was named Grace) and I have been making repairs lately. I figure I will sail her first before making any mast adjustments. She may be fine as is.
What are mast partners? There are some wedges around the mast but I gathers this is not the same as partners.
Actually I have not had a chance to actually sail the boat yet. She is an insurance salvage (was named Grace) and I have been making repairs lately. I figure I will sail her first before making any mast adjustments. She may be fine as is.
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Al Levesque
- Posts: 295
- Joined: Feb 6th, '05, 09:00
- Location: Athena CD33 #94 Salem MA
As Ed Haley mentioned, our CD33s also have a bolted base that the mast fits into. I don't know how much adjustment that allows but it would be the place to start. I don't know how much support we get from the mast collar as opposed to the old wooden partners of wooden boats but I have been inserting the wedges to support the mast with the assumption that the collar is well secured to the coach roof and therefore as valid as partners for supporting the mast.
Access to the mast base requires lifting the two filler sectionswith the mast hole cutout in the sole. They may be tight and may need to be pried out if they haven't been out lately.
Access to the mast base requires lifting the two filler sectionswith the mast hole cutout in the sole. They may be tight and may need to be pried out if they haven't been out lately.
The 33 should have a very straight mast measured from the toe rails and also from the waterline. This problem sounds odd to me as if there is either a different mast section in place or some serious change was made.
If it is as you say, a salvage boat, I wonder if there may have been a severe wrenching to the system that would set it aft that way.
Anyway, I would also start with the rigging as was said with the addition of checking that the mast is actually straight in a continuous column THROUGH the deck. A string should do the trick pulled through to the mast step.
Good luck with this. With the mast raked aft noticeably, I cannot imagine that the 33 would balance well under sail. You may find that you will need to move the step aft some.
Paul
ps The mast partners is the area where the mast goes through the deck. I believe it refers to the actual deck section surrounding the mast as in, " The deck must be very strong at the mast partners."
If it is as you say, a salvage boat, I wonder if there may have been a severe wrenching to the system that would set it aft that way.
Anyway, I would also start with the rigging as was said with the addition of checking that the mast is actually straight in a continuous column THROUGH the deck. A string should do the trick pulled through to the mast step.
Good luck with this. With the mast raked aft noticeably, I cannot imagine that the 33 would balance well under sail. You may find that you will need to move the step aft some.
Paul
ps The mast partners is the area where the mast goes through the deck. I believe it refers to the actual deck section surrounding the mast as in, " The deck must be very strong at the mast partners."