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F30 CK Centreboard movement

PostPosted: Sun Aug 25, 2019 5:49 pm
by AndyLamble
I own Tusitala (ex Freedom Freya) a F30 CK built by Fairways Marine in 1980. I have found that it is easy to rock the CB from side to side when it is in the raised position and on blocks (the boat is out of the water). I can move the trailing edge about 40mm from side to side by pushing sideways at the lifting tackle attachment point. What level of play is typical and/or to be aimed at when the bearing and pivot have been refurbished?

Andy
F30 CK Tusitala

Re: F30 CK Centreboard movement

PostPosted: Mon Aug 26, 2019 8:45 am
by Castaway
I replaced the bearing and, later, the rubbing pads on Castaway's centreboard, but it still moves, and bangs about in a seaway, just as it has done since we bought her. If you find a way to stop it, please let me know.

On the plus side, it's no worse after another ten years, and the boat continues to sail as well as ever. On the UK F35, the shape of the slot in the bottom of the boat matches the lowered CB quite closely, and that prevents any significant rotation of the board, which would be bad. Any lateral tilt is minimal and can have no effect. I expect the F30 is similar.

Replacing the bearing is quite a task; you have to be able to lift the front of the CB about 6", remove a pin at the top of the casing, then lower it all 6" below the keel to reach the pin and sleeve. Unlike the F40, the pin does not go through the hull, but is held in a yoke which slides up and down. On the F35, that is also held in place by bolts through the CB case above the waterline.

One other caveat; if you replace the pennant lifting the board, don't use thicker line than 10mm, because it binds on the sheaves and makes raising more difficult. 8mm Dyneema or the like might be better.

Regards,

Gerald

Re: F30 CK Centreboard movement

PostPosted: Mon Aug 26, 2019 5:18 pm
by AndyLamble
Gerald,

Thanks for your reply, my gut feeling is to leave it and monitor for any deterioration. The F30 doesn't seem to have any rubbing pads but as you say the CB case is quite closely shaped to match the lowered CB. I am considering putting in an illuminated inspection window in the CB case top so I can see what is going on as well as worry about the noise from any slamming... The original lifting tackle had 14mm polyester braid on braid and a 3:1 purchase which seemed to not run freely and was too heavy to winch easily so I have put in a 6:1 system and dropped to 10mm line. Another improvement will be to put a pin through the CB case and the CB lifting pennant attachment so that I can lock the CB in the raised position and relax the load on the pennant when she is at her mooring.

Andy
F30 CK Tusitala

Re: F30 CK Centreboard movement

PostPosted: Mon Aug 26, 2019 7:15 pm
by Castaway
Andy,

Be sure you can waterproof the pin mounting holes; the water sloshes back and forth in the CB casing in a seaway. I often hear the huffing sound of air blowing through the pipe carrying the pennant up to the deck as the boat pitches slightly.

The inspection window sounds useful. We keep so much stuff on the top of the case, it would rarely be visible. Again, waterproofing will be vital, especially since spillage at this point collects under the floor boards instead of draining straight into the bilge.

Gerald

Re: F30 CK Centreboard movement

PostPosted: Sat Aug 31, 2019 2:26 pm
by Goose13
If it makes u feel better, my Center Board knocks in most sea states when it’s down. It takes a little while to get use to the noise while on passage. But I’ve never seen any damage to the trunk when I’ve had it pulled for a bottom job.

Re: F30 CK Centreboard movement

PostPosted: Mon Sep 16, 2019 4:52 pm
by andygc
The F30 bearing is easier to get at than the F35 bearing. The yoke is held by bolts only - there is no pin to remove before lowering, so no lifting needed. The only difficulty might be the degree of violence needed to persuade the yoke to descend - we had to use a club hammer and a block of wood on top of the yoke. Yes, no rubbing pads, and the slot is a very close fit to the lowered CB. One thing to get right is the length of the limit strop - I've seen photographs of other F30s ashore with the CB lowered too far.

PS. You aren't likely to need to replace the bearing in your boat, which is a similar age to Feronia. She had a hard life with the original owner, sufficiently hard to break a mast and both wishbones, it appears, and a lot of long distance sailing, but the bearing has no slop in it.