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prestonrockstar
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Joined: 12/7/20
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Mast Pumping

Hi all,

I've owned my Catalina 36 MKI for a year now. Previous owner had just had the rig inspected. in 10+ knots of wind at anchor or at dock I get mast pumping and I can't imagine that's normal. Is it though?

I wrapped two spare halyards around the lower mast below the spreaders which aleviated pretty much all of the issue. But is there something more permanent? Is the rig just not tuned correctly?

Thanks,

Preston

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Sojourn
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Posts: 63

Preston,
The mast is out of tune.  On relatively calm day at the dock, loosen the rig.  Then tighten the lower shrouds to keep the mast vertical fore and aft and side to side.  Then tighten the head and back stay to center the mast and keep it vertical.  Then tighten the upper shrouds to keep it vertical side to side and fore and aft.  The should be no deflection to any thing by simply applying finger tension to stays or shrouds,  

Then go out for a sail in modest weather.  On  a beat, sight up the mast and correct any deflection on the stays or shrouds to keep the mast vertical.

Lou Bruska
Sojourn
1985 C-36 MK-1 hull 495

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Sojourn
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As a follow up, check mast wedges for loseness and/or missing wedges which could cause the mast move in the mast collar.  Also check to mast step and the base of the mast.  Damaged or malformation there could be the problem.  Lastly, look for evidence of the mast step moving.  Some of the boats in the past reported rotting under the mast step.  Look for cracks around the step and softness or sponginess there.    I have two friends that have had that problem.  One on a C-36 and the other on C&C-39.  If all is well, tuning may be the solution.

Lou Bruska
Sojourn
1985 C-36 MK1, hull 495

prestonrockstar
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Thank you for the replies! There are 3 wedges I can see from below. Two are tight, one is loose as all can be. Mast isn't centered in the hole, it's aligned to the left. I'm guessing that's no good. I assume it aligns properly when tuned properly. How scary is it to tune on your own for the first time? No special tools required just loosen and tighten and visually inspection the mast?

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Sojourn
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Preston,
Three wedges is not enough, they should surround the mast, at least six.  As for tuning, at dock is the start.  On the water is the fine tuning with mast under load.  Both are important, start with mast vertical, keep it that way under load.  It takes a little practice, but your eyes won't deceive you.

Good luck!

Lou
 

prestonrockstar
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Joined: 12/7/20
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So...I think I fixed the mast pumping. At the dock I can make the mast pump with ease if I yank on any of the stays. So I literally just tighted them all up...A LOT. until it's quite difficult for me to make the mast pump by hand. I wonder how "hand tight" the stays should be as I'm cranking. The backstay is pretty hard to turn now, whereas it was super easy when I started.

Also, nothing I did moved the mast side to side or forward to back. Inside, you can see it still sits port and aft in the deck hole. See photo's. Is that just normal?

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Chachere
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From the pictures it looks as if you are missing some of the wedges that keep the mast centered in the opening.

prestonrockstar
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Posts: 10

Ok...so it is definitely supposed to be centered then. Has anyone had to tackle recentering? I ordered the rubber wedges from Catalinadirect already, now reseaching and planning ahead. But no articles really go into any detail that I can find. I supposed you have to remove the mast boot, and then I guess just loosen every stay there is to allow the mast to be pushed or pulled into center so you can then hammer those wedges into place all the way around? I'm a little worried about loosening stays because I've never done that before, atleast not enough to allow the mast to move. Or will it still be too heavy to move? Do you just have to start wedging and by hammering in the wedges it centers the mast? Maybe you don't loosen the stays at all?

I truly appreciate all the replies. I'm tring to do the research myself,  just not finding much on this topic.

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Chachere
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Prestron -- you wrote "I guess just loosen every stay there is to allow the mast to be pushed or pulled into center so you can then hammer those wedges into place all the way around?"
You may find that you don't have to loosen the stays to do this.   I have had a wedge or two come out, and the mast was loose in the opening, and I was able to nudge the mast over and hammer the wedge back in. 
Either way, you'll probably want to check the mast afterward for alignment/trueness, and if necessary adjust the stays.

 

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Sojourn
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Basically, you got it.  As long as the threads are fully engaged in the turnbuckels all's well.  Loosen the back stay and all the rest of the shrouds.  The head stay may be covered up by the furler, it's no a big deal.  Yes, the mast boot needs to be loosen and raised.  One tip is: before tightening anything use a level below deck on the mast in two planes fore/aft and side to side.  This is the basic check to see if the mast is in vertical between the mast shoe and mast collar after the shims are in.  If the mast is vertical below deck, but off to one side, the shoe and collar might not actually be aligned.  Once everything trues up below deck, you can tune the mast at the dock, per above.  

Lou Bruska
Sojourn
1985 C-36 MK1, hull # 495

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Clifford Bassett
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Posts: 23

That advice from my friend Lou is what you need to do.  After you pull the boot up out of the way.

1.  Loosen all shrouds and the backstay.
2.  Put your wedges in, starting on the side that is in contact with the collar. 
     Make sure that the wedges only contact the collar, NOT the hole in the deck.
3.  With all the wedges in.  As many as you can get in the opening. 
     Make sure they do not contact the hole in the deck, they should only contact the collar. 
     You should adjust the upper shrouds to hand tight.
     Then take the Main Halyard and adjust it to just comes into contact with the outter genoa track on the port side.
     Then, using the same tension on the Main Halyard it should touch the outter track at the same point on the starboard side.
     This will center the mast head.
4.  Now you can adjust the lower shrouds uniformily, keeping the mast in column. 
     You can check whether straight by siting up the Main Sail Track,
5.  It has been my experience that the shrouds on a Catalina need to be quite tight.
6.  You can now tighten the Backstay. Very tight.
7.  You can check your tension as Lou suggested by going out for a sail and site up the Mast Main Sail Track.
8.  The Mast should stay in column under load.

NOTE :  The photo showing the wedge in the opening, that wedge is inserted incorrectly.  It appears to contact the opening in the deck.  That is a NO NO !  It should only contact the collar.

I hope this helps,  

Captain Cliff

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