Ken Surplice
Hi Folks, it has been a while since keel roller and the rear keel shock block have been discussed. As Vol-au-vent is on land at present I am looking into both and would like to pool tips.

I refer to the front roller in the hull opposite the bottom of leading edge of the keel. Fortunately my roller assembly was easily removed with a ratchet and socket applied to the two hex head machine screws with captive nuts embedded in the hull. The bracket and roller popped out without fuss. Unfortunately, although I had replaced the plastic roller some years ago, there was a large flat on It. It is the same as other rollers pictured here on older posts and the same as I saw in another 275, Sophia. I have a rollerthat doesn't roll. I read earlier posts suggesting to use acetal instead of nylon but I expect They will go he same way.

Idea: replace the plastic roller with a metal roller then apply paint mixed with grit/sand to encourage the roller to turn against the keel. I also received advice to soak the assembly in melted anhydrous lanolin to prevent marine growth from preventing rolling. That said, my roller did spin freely, just not when the keel moved against its flat. A stainless roller is being made and I will share the result in a year.

I refer to the plastic block in the hull opposite the bottom of the trailing edge of the keel. This block was split after gently introducing the keel to some rocks during a spell of highh pressure. Live and learn. This block is mounted with two countersunk slot head machine screws. There are two captive nuts. So far so good. Unfortunately getting a purchase in the slotted heads was tricky and one of the captive nuts has become a free range nut. The thread turns but does not withdraw.

Idea. Replace the slot head machine screws with hex head machine screws. The extra drag will be minimal. Any thoughts on this?

Question. With the keel raised, no problem even with the front roller removed, I will reach around the spinning ex-captive nut and try to secure it. But how do I secure the nut permanently once more? Grease the thread and apply epoxy round the nut? All advice readily accepted.

Idea.3D print a replacement block. I don't have a 3D printer but read that such printers can accept acetal filament. While shaping a new block by hand is not difficult, the thought of 3D printing appeals to me. Did anyone try it?

philip linsell
Hi Ken
The 26 does not have a roller, just a block, similar to the rear.
As your block is not turning it's acting in the same way as the 26 block.
If the keel goes up and down OK why not fit a block and stop fretting about non-turning rollers!
I know your keel is significantly heavier, but if it works.....
I don't see the need for grease etc, it's all water lubricated.
Ken Surplice
Hi Philip,

I get your point and appreciate that my non-turning roller is effectively already a slider block as you describe. As I have already ordered a metal roller I feel compelled to at least try that for now. Thanks for sharing your thinking and definitely food for thought for haul-out 2019!
Ken Surplice
Source of plastic block for aft keel buffer

I investigated where to buy a block of plastic to replace my aft keel buffer after it split during a grounding. Of all suppliers, a company trading on eBay offered by far the best value for money. 20mm thick white Delrin sheet cut to 80mm by 100mm cost £7.42 including postage. Delivery was prompt. 

Martin Watson
Hi Ken, I would urge caution in introducing two different metals under the water, ie, the stainless roller and the iron keel. Bi-metallic corrosion is very likely. If you have been using Acetal for the previous roller, you are aware that it swells in water? you should be using Delrin which was developed for use in water and is why it is widely used in the marine environment. As Phil has said, if it was working fine without turning, why not fit a fixed block a'la Super Seals and P27s and have done with it. It works for us so there is no reason it should not work for you. Ensinger in Waterlooville have offcuts of Delrin for only a few pounds if you go down to their warehouse, you are bound to find a suitable piece. I bought two large pieces as engine bearers for my boat because the engine mounts I was using were 30mm shorter than the old ones, they charged me £10. they were 30mm X 60mm X 400mm each. They have racks and racks of offcuts of all sizes, but you do need to visit, they don't sell offcuts by mail. Happy sailing!
Martin Watson
Martin Watson
PS, Ken, just saw you last post regarding source of Delrin, I think you'll find Ensinger is considerably cheaper than you were charged on Ebay!
Martin Watson
Ken Surplice
Hi Martin, you are a mine of useful advice and information. This comes at a time when Vol-au-vent has finished her time ashore and is once more afloat 😉. Despite spending a good while on insulating the stainless steel bolts from my aluminium rudder stock, it did not occur to me to be on the alert concerning a stainless roller and the cast iron keel. While the paint on the leading edge of the keel inevitably wears away, leading to stainless to iron contact, I do recall that the keel clears the roller when it is up. We will see how it has progressed at next crane out.

Thanks for the tip on Delrin. I don't know what was in my roller before. I just know that it developed a flat. So in effect it was a slider and I could simply leave it to wear away further.

I'll be very interested in your experience with the s/s roller.

When I first removed my roller it had the flat you describe. I removed the tack-welded axle, made a new axle with a removable retainer, and a Delrin roller [Delrin is Acetal Homopolymer, Acetal is normally the copolymer, so they have quite similar properties - Nylon is the stuff that swells in water].

Since then I have replaced the roller again after it developed a new flat, and expect that this may be required periodically. The loading on the roller is very high as the keel approaches the fully down position - from memory about 1.5 tonnes according to my sums. So the other problem is that the super paint coating on my keel disappears from the top 9 inches of the leading edge.

I also needed to replace the aft block. I couldn't remove the screws as the captive nuts rotated - it required much work with a Dremel to remove the block from around them and cut them. I them had to Dremel away all the stuff around the non-captive nuts. I cut a piece of 5mm stainless to fit around the back of the keel and against the inside of the keel box with two tapped holes for the retaining screws, and epoxied that in place. I got 20mm Delrin as you have, and with much patience and a profile gauge made it fit. I haven't tried to remove that since it was installed a few years ago. I have tried to be more careful about running into things though.

Dark Star P275 No 36
Ken Surplice

I will be happy to report on my stainless steel roller around October when Vol-au-vent is craned out. I raise the keel manually, via winch, and it does seem to be a little easier than it was with my delrin roller with flat. I'm hoping electrolytic action is minimal as the keel is clear of the keel when the keel is fully raised.

It took me ages to fit the rear block. The final shape wins no prizes for fit and elegance but it seems to work. Like you, I found the captured nuts were rotating. With a combination of isopon and specially purchased right-angle pliers I managed to get the bolts to hold. And also like you I am a tad more sensitive about running aground.

My 275 /34 is now out at PYC. The Keel roller dropped out as we hauled her out. I have the roller. I find the bolts were held in with Sika and cant seem to find the captive nuts, no matter how much prodding. I could do with your advice on what you did when you fixed yours. And if you are about Parkstone at any stage that would be even better. Many thanks. Liam
Ken Surplice
Hi Liam,
Alas my annual visit to Parkstone was for the recent curry night and I recall chatting with you there. If I may be permitted a second “alas”, it has been a while since I prodded around the keel roller area, especially as it has worked so well. From memory, I think I also struggled with the captive nuts. Only one was in place and I ended up slathering a load of Isopon (the thick one with fibres embedded) to strengthen the area and stick in a new nut.

As Peter Lowry went through a similar exercise more recently than I did, but using a bushed delrin roller, I will speak to him tomorrow and ask if he can offer some advice here.

In this era of camera phones, I must get into the habit of photographing anything I do and sharing the photos in this forum.
Many thanks Ken. I will dig a bit further.
peter lowry
Hi Liam.
Yes I had the a similar problem with the captive nuts.
I put new nuts and bolts onto the roller and offered it in place.
Leaving about 2 turns yo tighten up hard.
I mixed up fibral,,,, its a upol product of chopstrand glass fiber.
I packed the area inside the keel box and left it yo harden.this encapsulated the nuts once hard I was able to remove the bolts for permanent fitting of roller .

I hope this makes sense .if u are in any doubt, give me a call.
Peter Lowry
275 Sophia
Thanks Peter.
After a bit if digging around, I found one of the nuts, still captive and secured the plate with a longer bolt. I replaced the other nut and epoxy'd that in place and was able to get a bolt in there also. So hopefully now all set.

Click to View Image1 View(s)

Well my keel woes continue. After haul out, bottom scrub, polish, new decals, resecuring of the front keel roller and keel wire with Dyneema and relaunch, the keel appeared to be working well. However, 1 month in and the keel has jammed yet again. I did nudge the mud a couple of times and am wondering if this has canted the keel backwards and jammed it in the slot. The Delrin shock block at the rear of the keel slot was split when I hauled out and I did not replace. Is it likely that as a result the keel has become jammed and I should replace this?
Please ignore above. All resolved. Applied a bit more force to the winch handle on the Electric Winch drum and got it moving. Appears the clutch may need adjusting and a bit of Waterproof grease in the box.
Ken Surplice
Hi Liam, fingers crossed that you reach a stage where you are fully confident with your keel setup.

Two things for you:
1. When raising the keel it is important to keep tension on the telltale line so it doesn’t flop down the side of the keel and create a jam
2. My electric keel winch occasionally does not want to lower. If I apply a dab of up and then immediately down it works. I’m sure this is clutch related but have kept putting off giving it a clean with isopropyl alcohol or similar. Now I’ve read your comment I will be sure to get around to it.

By the way, I’ve never encountered a jam due to mud or stones entering the keel box.