Big Block on my Swan 38 deck
Thanks Professor, but what is the right way to move the center pin? There is a special movement? Have I to un screw in a special way? I don't want to brake something. Thanks.

Check inside the base under the block whether there is a nut on the center pin lower end. If not, the pin is held by the little screw in the rectangular plate on the upper side.

By removing the nuts on the lower ends of the other bolts the block can be removed from the base.

Kind regards

Lars

I am under the impression that the professor's answer was a bit short (sorry Lars!). I personally have been fighting with these blocks for a few years as they had never been dismantled, and the sheaves were far from turning freely on our Swan 41 from 1975.

So this was my solution.

1: Undo the four nuts under the aluminium plate where the blocks are supported. To do this you might have to cut a wrench, as there is not much place inside the aluminium support, and the four srews are probably stuck by corrosion inside the blocks.

2: undo the small screw holding the top stainless steel plate. You might need an impact screwdriver (indispensable on our vintage yachts!), and the head of the screw will probably break, so drill it to the point of being sure it will not interfere when you turn the stainless steel plate.

3: The stailess steel plate mentioned above is welded to the axle of the sheaves, and this axle is sitself threaded, and screwed to the bottom part of the block. At least on our boat, there is no nut on the underside to hold this axle. Then comes the "horrible" work! The block beeing upside down, you have to clamp as hard as possible the stainless steel plate in a strong vice, and using a good wooden hammer, unscrew the aluminium block. It is most probably stuck by corrosion and heavy hammering is needed. So be careful not to hammer in weak places, and use a mallet, not a hammer.

As far as we are concerned we take off these blocks evry year when winterizing, and also have added nylon washers so as to isolate the block from their supporting plates.

I hope this was not a too long story! Best regards.

Ph. Vidal 41/022

Dear Philippe

Thank you for your thorough explanation. Contrary to me you have access to the fitting in question, and this enables you to evaluate matters much more in detail.

Best regards

Lars

I am under the impression that the professor's answer was a bit short (sorry Lars!). I personally have been fighting with these blocks for a few years as they had never been dismantled, and the sheaves were far from turning freely on our Swan 41 from 1975.

Hello Philippe,

On my 41, I just removed the footblocks still attached to the aluminium base. Indeed there is very little space to remove the bolts. The bolts of the footblock itself are stuck, I guess due to corrosion.

The sheaves are turning badly, I wonder what you have done to get them work properly. Did you replace the sheaves for ball bearing ones? Or something else?

Thank you in advance for your reply.

Best regards,

Maurice van der Loop

41/030 Spica

Dear Maurice

here is what I did on my own ones.

once I got the sheeves out of the blocks (that was easy following The Professor's instruction), I have sanded them on top and on the bottom with very smooth sandind paper attached to a plat surface, so I did not consume them but just cleaned the very very properly. Now they are working absolutely free.

Fair wind!

Matteo (38/067 Only You)

Dear Maurice,

I also have been thinking of buying new blocks, but look at the price for similar size blocks: not worth it a minute!

On our 41/022 we have been undoing the blocks from the aluminium support undoing only the nuts, as the screws where stuck fast in the blocks by corrosion. Undoing the nuts requires thin hands and a short (IE: cut) wrench as explained. But its relatively easy. Be patient enough!

After that, the really difficult bit is to unscrew the axles if they are made the same way as ours. That is if there is no bolt underneath (the stainless steel axle has a thin thread in the bottom aluminium flange of the block). In that case you have to do as explained above, being especially careful at where you hit the block with the mallet, as it's obviously not designed to receive such a treatment!

When everything is dismantled, you will find that dust, and probably salt are responsible for the mess. Rinsing with fresh water does the trick, no problem at all, they will work like brand new ones.

Now we take them away from the aluminium support every winter, rinse them thouroughly, and leave them inside the boat.

Sorry I mised another point.

After undoing the 4 nuts under the blocks, you might also have to use a mallet to separate the blocks from their aluminium supports which have to be bolted to something strong (in our case: the deck). Hitting them alternatively on each side should do the trick.

Sorry for this long story!

Kind regards, and happy sailing.

Philippe V 41/022

Dear Philippe and Matteo,

Thank you very much for your input. It is a great help. Finally, I got the axles out and cleaned the parts thorougly. I noticed that there is al lot of space (app. 1 mm) between the plastic (delrin?) bearing and the stainless bushing on the axle. This space make the sheave tilt and touch the aluminium housing. I pressed down the plasic bearing a bit to compensate. I wonder if this is normal and if Nautor can provide new bushings. If not, do you know of what material the bearings are?

Thank you again for your help and happy sailing to you too!

Maurice 41/030

Maurice,

There should be only minimum play between the delrin and stainless steel sleeves. Perhaps yours are worn out, which was not the case for us, and you should have new ones manufactured which should not be too difficult (leave sufficent play as nylon takes a bit of water). Also there should be large tufnol (the usual brown phenolic impreganted fabric used by Nautor in lots of places) washers on each side of each aluminium sheave which should prevent what you mention.

Kind regards.

PhilippeV 41/022

Dear Philippe,

Thank you again for your information. I will have new delrin bushings produced. The tufnol washers are ok.

Maurice 41/030