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How to check condition / for excess play in the pivot of the RL28 keel
I have a knock eminating from the keel of my RL28 when anchored in a swell with the keel down. I'm interpreting this as possibly being due to loosness in the keel pivot pin - or perhaps there's another cause.
Either way, I guess at some time I will need to check the keel pivot.

Some questions:
* is it accessible - and if so how and where?
* is it related to the formed fibreglass bulge just outside the bathroom above floor level on the centreline?
* what maintenance is appropriate for the pivot pin?
* (on a slightly different topic) the leverage exerted on the lift cable when close to the top of its travel by 400kg of keel must be very high?
* any other related thoughts / experiences from RL28-ers?

All comments appreciated....

Phil Gardam12-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
A knock when anchored is quite normal because of the clearance around the pivot bolt. This happened in mine from new. Just raise the board one third and it generally stops.
Not sure about the "bulge" but it sounds like it is in the right place for the bolt. Mine is not covered but is completely smothered in silicon sealer. It is simply a very large diameter stainless steel bolt but I have never removed it.

There would be considerable pull from the centreboard and most are fitted with a stainless bar from the hydraulic slave cylinder to the centreboard rather than cable. However, I fitted a cable with a loop from the hydraulic cylinder mounting bracket so that when the board is fully raised, I can put the loop around the horizontal pin and take the strain off the hydraulics. This seems necessary because my boat is stored in the water with the board raised and I didn't want the hydraulics to have to hold the board weight constantly.

Keith Merkley12-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
The downward pull on your hydraulics is approx 800k and the pivot bolt which in your case is under those bubbles has an UPWARD load when the keel is raised of approx 400k. The bolt was designed as a pivot only and takes no side load as it has a 3mm less diam than the hole in the keel. All load when heeled is taken on the solid material in the keel and heel, when the keel is raised the case sides restrict the movement. IMPORTANT , if your keel bolt is not leaking, leave it alone. Regards Rob Legg.
Rob Legg.12-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
Thanks for the info and thoughts Keith and Rob - I will rest easier at anchor and will not be tempted to tinker with the pin! The pin and keel loadings are interesting and there are certainly no leaks evident near the pin.
As an aside, I do feel less aprehensive in an RL28 in shallow water knowing that the keel can pivot if needed - as opposed to some other drop keel trailer-sailers. Obviously I try to avoid bumping things if possible but I also enjoy cruising over relatively shallow banks.

I should have flowcharted my process for attaching a temporary line and raising the keel when the lift wire broke at Peel Island. Not a trivial task. 1) Drop Sinker on fishing line down centre-board case 2) dive under boat get sinker 3) tie line to rope 4) pull rope up through case 5) tie spanner to safety line 6) remove keel shackle 7) tie rope to keel... etc OK for Jacques Costeau, but I'm no Kieren Perkins!
I'd be very interested to hear (if Rob has a chance) whether in the design years of the RL28 he needed to experiment with lots of different keel weights / placements / shapes / angle when fully down? Were scale models part of the design process? I would love to hear details if we can encourage you, Rob to lend us an hour or two?
Phil Gardam14-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
CORRECTION ---- Sorry Phil The weights in my previous response should read Lbs not Kgs, They were taken off the origonal calculations and at that time material strenghs and costs were still rated that way.
Rob Legg15-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
My rl28 has an exposed bolthead in the passage and in the shower with a large stainless nut and big washer on each side. Under the washer is an O ring. When I got the boat it was dry and in a marina. I found after getting it here to SA it started leaking after raising and lowering a few times. I replaced one of the o rings which had broken but the size was a guess and the correct specification o ring would make me feel happier. So far I have not managed to get the both sides to seal properly and stay dry,also the bolt seems to rotate with the keel, This tends to undo one side. I have now tried threadseal tape to try to lock the nut onto the bolt and used marine grease to allow the washer to slide over the o ring, I will let you know if this succeeds. The bolt is very firm when the nuts are off and if there is 3 mm play in the hole through the keel, I can just hope that if the weight was taken off the keel it would become free in case I ever need to get the keel out, unless the keel has rusted onto the bolt. Could I ask rob to outline the proceedure for keel removal for future reference and also to elaborate on the O ring size. The side which seems to leak is into the shower. I assume this side should not be able to leak down into the bilge, mine does and I have ended up with wet carpets after a week in the water. Is is possible to get to the sump on the shower and reseal it and the connections so water can be pumped out into the keelbox rather than ending up in the bilge?
mike barnden26-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
Mike. We never used O rings but sealed with Silicone. It sounds like your keel has a build up of corrosion caused by a lack of use over a long period ( this is unusual) I would loosen off the nut and give the bolt a good whack with a hammer then try turning with a spanner. when free re seal under washers with silicone. It sounds like your boat may have been finiahed off from a kit, as the shower should pump out directly from the shower recess. IMPORTANT Do not over tighten the pivot bolt nut. Let me know how you get on.
Rob Legg27-Apr-2005    Edit    Delete 
Re: How to check condition / for excess play in the pivot of the RL28 keel
Thanks Rob for your prompt reply. Something is not standard on my boat I guess. The keel bolt is not a bolt but a stud with thread in both the passage and shower sides. It seems to revolve with the keel in what appears to be a glassed in metal bush. Each side of the stud has a groove in it suitable for the O ring which is what I found under the washer on both sides. When I pull it up on the trailer next I will attempt to free the stud within the keel but obviously I have to be careful not to damage the thread on either side. I guess a solid brass drift and a 3 lb hammer may do the job. At the moment the boat is dry no leaks but I have yet to drop and raise the keel. If the washers rotate on the o rings and the nuts stay nipped up it may stay dry. If the design had a bolt with a bolthead a good twist would free it if it has rusted in the hole through the keel particularly with a bit of persuasive shock. There is not enough thread to put a pair of nuts onto one side or the other and lock them together so that I could rotate the stud. It may be a few weeks before I pull the boat up onto the trailer next to try out some techniques to free the stud within the keel. If you have any other thoughts I would be greatful for them.
Mike Barnden2-May-2005    Edit    Delete 

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