MERLIN ROCKET FORUM

Topic : Slot gaskets and sticky boards

The boat is a Mk1 Winder and I'm pretty sure the board isn't tight in the slot and that we dont have to much friction on... but we are having trouble getting the board up and down.

Its only at when its nearly up or your only just starting to put it down so I guess its the gasket. Its still there (I know as I have to reach under the boat to push the last bit of the board in when coming a shore) but haven't looked any further.

What normally goes wrong here and what's the trick?

Thanks
Ian and Hannah
3581
Prologue


Posted: 09/11/2009 08:07:51
By: Ian and Hannah
mines the same 3563 also chris Martin has bought a mk1 around the same number and his is the same as well. we find a quick push on the top of the board with a foot solves the problem just as you come in.


Posted: 09/11/2009 08:17:33
By: Paul Hollis
Now that's impressive... 10 min and we already have a comment!

The problem is that the crew is only 50kg and she can jump and down on it, pushing it forward with her feet at the same time, all with no affect... I really do need to do something. Frustratingly its getting worse now that the water is getting colder :-s

Ian and Hannah


Posted: 09/11/2009 08:41:53
By: Ian and Hannah
I used a silicone spray on 3569 and that helped


Posted: 09/11/2009 12:17:47
By: Mike
I was a bit nervous of doing that as although we haven’t yet had to stand on the board... the time will come… and that sounds like a recipe for disaster. 

Ian


Posted: 09/11/2009 16:58:11
By: Ian
I recently changed my centreboard and the new board was terribly difficult to lower or raise,even the 11 stone crew couldn't make any impression on it.I just sanded the top layer of paint off when using "GT3" lubricant failed to make any difference ; works like a silky smooth dream now, but I was VERY careful.


Posted: 09/11/2009 17:15:08
By: Ben 3634
This seems to be a common issue. I now have control lines on mine, and it can be tight at the top if the board is dry (a good idea to wash salt out if sail on the sea.) I often spray some oil on the head of the board which really helps. Silcone based might not wash off as quickly as WD40?, but WD40 seems to work fine.


Posted: 09/11/2009 17:33:36
By: Ross
3581 was always terribly stiff. When Mike Anslow had it we tried numerous times to loosen it but came to the conclusion that the box was tight.

I remember after one race at midland Mike hooking the (detached) brake out of the box having not noticed any differance in the tightness of the board!

Prolube works in the short term but is a pain if you capsize.

3583 is tight for the last 4 inches, but otherwise fine and i've had to fit a brake to it.


Posted: 09/11/2009 21:39:44
By: Chris M
The raking board will be fitted to 3583 soon hopefully by the way. I'm doing mine myself, but i don't think it's that expensive to have done and solves a multitude of problems. I think the fittings cost about £70 and if you've got a boat to copy or good photos i reckon about 3 to 4 hours to do with the correct tools.


Posted: 09/11/2009 21:47:33
By: Chris M
Thanks for all the replies people... I guess its good to know that its not just us although its a shame that no one seems to have found a complete answer to the problem.

Has any one tried a new gasket, or indeed a different type to see if that helps...

Regards
Ian and Hannah


Posted: 09/11/2009 22:19:05
By: Ian and Hannah
I think the cases narrow at the front. I've never measured it but i'm sure that this is why. It may even be deliberate to stop the board dropping down whilst towing and wearing away the front. Yours was always the tightest i've known, i think Mike even had the board sanded down very slightly.

One solution - albeit expensive - may be a new board, 3565 has had a new board which has jap tape on it so for whatever reason must be looser.


Posted: 10/11/2009 07:16:52
By: Chris M
Is the case flexible enough to allow a fat wedge to be tapped into the front, to part the sides slightly? Or maybe that's a bad idea...


Posted: 10/11/2009 09:04:36
By: Mags
By way of reply to Mags, I wouldn't put any strain on the case at all - and the strain a wedge would impart is impossible to judge.  My guess is that would lead to more serious trouble in the long term.  Thinning the board would be the preferred way to go as it would always relieve the strain rather than add strain to the case as a wedge would do. Silicone is all very well in the right place but a devil to remove when required (see Katie Price)!!  Seriously, if you ever want to repaint you will find it's not just on the board but on the hull and everywhere and nothing will stick to it.


Posted: 10/11/2009 09:13:58
By: Garry R
�70 - that seems a little optomistic to me. I recon you need somthing like 18 blocks to do the job?


Posted: 10/11/2009 09:36:01
By: Dave
Yes you're right i'd missed a ey out! 2 in the top of the board 4 through deck 2 cheek 4 to route the lines 4 under inwhale and 4 to soak away.


Posted: 10/11/2009 10:55:02
By: Chris m
I'm not convinced that the board is binding at any point... it only seems tight at about 10 deg down, past this in either direction it free's up, and if I take out the bolt it is free to move in all directions at all points.

Perhaps the solution is to give up trying to fix the problem and to concentrate on making it easier to live with... maybe some form of up haul down haul is the solution.

I'll give it some thought... does any one have some pictures or a proven solution?

Regards
Ian and Hannah


Posted: 10/11/2009 11:43:43
By: Ian
A couple of these photos show the CB controls

http://www.merlinrocket.co.uk/gallery/default.asp?folder=gallery/rigging_guide/3683

Posted: 10/11/2009 12:48:02
By: Mags
I spent alot of time staring at the upturned hull of a previous boat trying to work out why the board was so stiff at the shallow angle, and it eventually dawned on me that due to a slight curve down the leading edge of the board, it is in contact along almost all of it's length with the slot gasket. If the gasket is firm or pretty rigid, it requires a fair bit of force just to get past that point- to burst through the slot gasket.
When the board is fully down / vertical, it has the least contact with the gasket and moves more freely.
I can't say that this is the cause of the problems described earlier - just that even with clearance in the case, there is still a gasket resistance to overcome at that shallow angle.
I was using a stiff mylar slot gasket which I wouldn't use again.


Posted: 10/11/2009 13:08:11
By: KM3548
Hi Ian.  I owned the boat from new and, as time went on, the board got more difficult to operate - particularly between halfway and fully retracted.  It had been stiff from the start and eventually it became necessary for the crew to jump up and down on the board to get the last quarter into the box.  As Chris Martin said, I did try Prolube, which was quite effective, but it became difficult to right the boat after a capsize with the centreboard like a skating rink!

We thought the board was a tight fit in the box and that it had nothing to do with the slot gasket. It might be worth having a word with Dave Winder to see if he has any advice.

Mike


Posted: 10/11/2009 20:34:29
By: Mike Anslow
I had the same problem - the board is in contact at a shallow angle over its full length - I spoke to David W and asked if it was OK to sand a bit off the board and he said it was no problem. I put the boat on its side (slot gaskets removed) As you lower the board it contacted both sides of the box at the bottom - a pencil mark and a light sand - try again - more pencil marks and after several very slight sanding off of the pencil marks the board was just tight enough - but easy to move again - dont suppose more than .5mm was sanded off - And David ws insure of why this had happened! Its a tedious job but well worth the effort - oh and removing and replacing the slot gasket is tricky - I can tell you how to do it if any wants to know


Posted: 11/11/2009 08:49:04
By: the gurn
Swelling do to water ingress? Osmosis in the GRP of the case?


Posted: 11/11/2009 09:41:41
By: ?
Link to Mike Macs guide about putting a slot gasket on...

http://www.wayfarer-international.org/WIT/maint.repair.ref/CB.rudder/Slot.Gaskets/MikeOnGaskets1.PDF

Posted: 11/11/2009 12:39:34
By: Blackie
Quite often fine particles get trapped in the gap between the surfaces causing a lot of friction. As a point of maintenance, I used to/do draw a pencil line along the board when stowed and another couple of lines (above case) directing through the bolt prior to removal. Then remove the board, rub down contacting surfaces with 800, 1200 and finally 2000 grit wet & dry and do any repairs to the board. Then using similar solutions to either yacht wax - UV systems or as used on cars, coat the board (make sure you reinstate the pencil lines) and refit the board. Also assists with the slot gasket issue. Assuming no major repairs to board, the whole operation should take no more than 1.5 - 2.0 hours first time and then less than an hour thereafter. For us it is in the most important jobs in maintaining or running up a boat towards a major regatta.


Posted: 11/11/2009 12:59:41
By: barnsie
removing the brass strips is the trick bit


Posted: 11/11/2009 18:41:36
By: the gurn
so how do you remove the brass strips without damaging them?


Posted: 12/11/2009 09:04:50
By: Interested
Depends how they are fixed to the hull. Assuming that they are used to hold the slot gasket on, they will have fixings through them, the gasket and into the hull. In most cases this is done with small brass screws - carefully unscrew to remove strip and then prise strip up very gently, using something like a wide wallpaper scraper, to avoid snapping it at at the screw holes. However, it might be held on with brass pins, which is a bit bit more fiddly. You'll need to get a small pair of pinchers whose jaws will get under the head of the pins so that you can pull them out. Be careful not to chop the head off the pin in the process. Or, again using a wide scraper either side of each pin, lever the strip up very gently until you can grip the pin head with the scrapers removed. 

The big thing to remember is that the strip will snap at the screw/pin holes if not treated very carefully.

If the strips don't hold the gasket down, there shouldn't be any need to remove them.

...or have I missed the point of the question?


Posted: 12/11/2009 11:30:49
By: Alistair
I would budget to replace the brass strips as your chance of being able to remove the strips without kinking them is pretty remote.  Most will be held on with pins and glue.  Good luck.


Posted: 12/11/2009 12:34:28
By: Andrew M
ouch! that sounds expensive if it needs doing a couple of times a season as Barnsie suggests - which I don't doubt. P+B charge £20 per metre for brass, and about £13.00 for alloy - probably 3 or 4 metres needed to do both sides?


Posted: 12/11/2009 13:17:29
By: ;)
I don't think that anybody is advocating replacing the slot gasket every/any time you take the board out of the boat. Unless you are particulalry ham-fisted, you should be able to get the board in and out without damaging the gasket.


Posted: 12/11/2009 13:37:21
By: Alistair
The maintenance I was refering to on the plate, was to avoid the stiffness, wear on the slot gasket and drag generated by the plate if not in the correct position or if damaged. Interestingly, I only ever had to replace a slot gasket once and that was due to issues with a trolley folding the gasket tape over. Maintenance should prevent the issue of replacement. If pinning into wood, make sure you either coat the pin end in varnish of epoxy to avoid ingress of water into the wood.


Posted: 12/11/2009 14:53:00
By: barnsie
Agreed but previous posts advocated replacement of the brass strip each time, not necessarily the gasket, as removal of the strip was likely to result in damage, and in my experience the strip does usually keep the gasket down. 
Am I missing some trick where the board can be removed without disturbing the slot gasket and strips that hold it down?


Posted: 12/11/2009 15:46:36
By: ;)
I haven't got a Winder but I have taken out the board a few times and have never replaced the slot gasket to do it, have always felt if it looked and felt OK it would cause more trouble to try and change it.  Pull board up into boat from fully down position once bolt is out.  Replacement as they say in the Haynes manuals is a reversal of the removal procedure - drop into boat and push straight down.  Magic marker lines radiating out from the hole are an enormous help in locating it.


Posted: 12/11/2009 18:13:10
By: AndrewM
I can get mine in and out without pushing it down through the slot (oh er missus). The lack of kingpost makes it easy.

As well as the lines pointing to the hole, use a mirror so you dont have to lean right into the boat with your face on the floor!


Posted: 12/11/2009 21:14:57
By: Mags
For what its worth.  Boat on its side.  Slide the board in horizontally from the inside of the boat with the hole in the board lined up as best as you can to the holes in the case. This also has the effect of pushing the gasket to the outside of the hull.  Use a wooden bodger with a bigger handle than the hole on the top hole of the case to locate and line up the holes, remove it without allowing the board to move and put the bolt in.  Not rocket (or Merlin Rocket) science.  10 min job.


Posted: 13/11/2009 00:14:04
By: Garry R
on my winder Mk 1 the brass strips are held in place with copper pins - about 18mm long - the sort that used to be used for nailing down hardboard over old floors. A pack costs about £1 from B & Q

If you make a tool with a V cut out of an old sharp chisel or similar you can tap it in from the side and prise the pins out. As the brass strip is very thin - maybe 1/4" and the holes are countersunk it is very fragile! It will break at the countersinking points - so essential to prise both sides at once. But I managed to remove mine and refix with new pins and a bit of glue - cant remember what type I used. This also allows you to reuse the holes reducing the possibility of extra redundant holes to absorb water.

You just have to be patient. I would be very difficult to make up new strips with the holes in exacly the right places and properly countersunk - DW does a good job!


Posted: 13/11/2009 07:23:12
By: the gurn
You could carefully Dremmel the heads off all the pins and then lift the strip off with no bending involved. You should then have enough of the pin shaft left to pull the pin out quite easily. This would negate the possibility of the strip snapping at the pinholes.


Posted: 13/11/2009 08:44:45
By: Alistair
Just an update really...

I gave up trying to work out why it was so tight and have just put a 2:1 uphaul on it. Hannah can now stand on the centreboard and pull on the rope and it comes up easily.

Not exactly problem solved but it is at least, problem moved to the side until I find the time to look into it properly.

Thanks for all the advice guys

Ian and Hannah
3581


Posted: 29/11/2009 19:38:47
By: Ian and Hannah
We've just fitted the raking board to 3583. Very good and removes the sticky last 3 inches.


Posted: 30/11/2009 08:16:35
By: Chris M
I recently replaced the gasket on my boat with Mylar. The board goes down fine but when I raise it I cannot retract all the board. With the boat on it's side it would appear the last section of board wants to invert the mylar with the mylar stopping the board from retracting fully. Any help or suggestions would be much appreciated. My crew is a very capable 72 year old sailor but I haven't the heart to suggest jumping up and down on the board! Thanks.


Posted: 01/10/2011 21:13:07
By: Richard Battey
spray some of that slippery aerosol stuff on it and in a while it will 'ride up with wear'


Posted: 02/10/2011 00:03:43
By: John
All sorted! Sprayed with WD40 now works a dream. Thanks.


Posted: 02/10/2011 20:23:47
By: Richard Battey
My light sanding as described above solved the problem andhave never needed any sprays or silicone again. It takes a long time to do it but its worth it


Posted: 03/10/2011 08:45:12
By: the gurn

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