peter lowry
2020-12-06T07:30:34Z
A Lift Keel Misadventure

“Dawnchild” is a Parker 285 fitted with an electric winch to raise and lower the keel, controlled by relays and two buttons in the cockpit. Her home mooring is a marina at Brundall off the River Yare, which is part of the Norfolk Broads system. A mile or so down river two channels lead into opposite ends of Rockland Broad. The broad is heavily silted and shallow apart from a dredged channel between the two entrances and Rockland village. After sailing on the river we often go into the broad for a quiet tea. We set the keel at rudder depth and leave the channel until it feels the mud, then lower it fully to “anchor” and lift it to leave without bringing mud on board.

On a sunny day last September we set out for a sail on the river, but decided to have lunch on Rockland Broad first. The tide was unusually high and we got a hundred feet from the channel and close to shore before feeling the mud and “anchoring”. We enjoyed a quiet lunch watching a large flock of Canada geese gliding round the broad. The wind was off the shore so all we had to do was raise the keel and we would blow back into the channel, but when I pressed the button there was a horrible crunchy bang, followed by whirring with no movement of the keel position indicator flag. Removing the keel box cover revealed frayed ends of a broken lift wire. So there we were half an hour before an exceptionally high water with half a metre of keel already embedded in the mud and no possibility of raising it. Visions of having to hire a costly floating dredger to get out went through my mind! Putting the engine on full power and rudder hard over screwed us round to face the channel and waggling the rudder we slowly moved forward ten feet before sticking. Sheila phoned the marina and asked them to send their workboat quickly to add a tow. After a few minutes it occurred to me to reverse back along the groove already cut and surge forward. With a slight bump we cut through the stiff bit and slowly regained the channel, just in time to phone the marina and stop their workboat setting out. We motored back without further incident and into our berth at high water, where we would again be stuck in the mud at low tide.

The winch is an American made Strongarm, originally sold as a trailer winch complete with 5 mm diameter flexible stainless steel wire. Bill Parker increased this to 6 mm for extra safety, no doubt thinking of the disastrous consequences of dropping a 700 lb keel from fully raised. I think the 6 mm flexible wire was too stiff to turn comfortably onto the one inch diameter winch shaft; the first layer was badly crushed and permanently coiled when removed. After consultation with Jimmy Green Marine I obtained from them 6 mm Dynice made up with a hard eye splice and new shackle. This high tech rope was stated to have a breaking strain of 6000kg, but was much more flexible than the wire and easily wound onto the winch. On a convenient high water “Dawnchild” was lifted out and lowered onto hard standing to push the keel back into its box and allow connection of the new cable.

“Dawnchild” was launched in April 2001 and regular inspections showed a few prickles appearing on the wire by November 2009 when I replaced it. I confess to my shame I had made no recent inspection before it broke. I suppose some force to pull the keel out of the mud was added to keel weight and the winch end of the wire was in much the worst condition, so perhaps we were not quite as close as we seemed to the ultimate disaster of dropping the keel from raised. Nevertheless the need for regular inspection including removal of the winch cover has definitely been relearnt.

Paul Ashford

Ken Surplice
2020-12-06T22:57:34Z


Hi Paul. Many thanks for sharing your story. I’m on my third winch now but have a modified Strongarm model that I expect to last a lifetime. Like you, I chose, or rather I was advised, to switch from wire to dyneema. The more I see using it the greater my peace of mind 😁.

The real reason for my reply is to share a little more advice. As I was buying my dyneema and checking it fitted comfortably in my metal pulley that goes above the keel, there was a sharp sucking of teeth by the rigger supplying the rope. “Did that pulley used to have wire on it?”. “Er, yes”. “You’ll be needing to have the nicks smoothed out or it will cut the dyneema”. With that, I toodled off to a nearby machine shop to empty my wallet.

Converting your winch from wire to high strength rope? Only smooth pulleys need apply.

Ken Surplice
Paul Gray
2020-12-07T14:41:48Z
Thought I would follow-up with another cautionary tale………….

Indianna is fitted with a Dutton Lainson winch on deck immediately above the keel box. The winch cable is 10mm dyneema.

According to the previous owner, the existing cable was fitted to Indianna approximately 5 years ago. During the 3 years that we’ve owned her, we have periodically inspected the cable and it always looked in perfect condition so we decided to keep an eye on it but not replace it. This inspection regime followed on from ‘expert’ advice that the condition of dyneema cables can be determined by examining the outer sheathing; if it is intact, there should be no problem.

However, this summer we discovered that the outer sheathing of the cable was damaged over a short length adjacent to the root diameter of the winch drum. With the cable subsequently removed from the winch drum we noted a number of raised welds covered in surface rust where the side-plates of the drum are welded to the central core.

By winding the cable over the drum from fully extended, it was evident that the damaged area of the cable was just at the point where the initially unloaded coils of cable, having been loosely wound around the core, would then tighten up as the full weight of the keel tensioned the cable. It was exactly at this point that the cable came into contact with the rusty welds.

During this initial take-up of the full keel load, the cable would be dragged under quite high loadings around the rusty welded area which acted as a very effective abrasive. Not surprising that this action abraded the cable sheath at this point.

The cable was subsequently replaced by another dyneema cable purchased from Jimmy Green Marine. The cable was manufactured by Marlow Ropes, designated ‘Marlow 8mm D2 Racing 78’ with a specified minimum breaking load of 3140kg. This should give a decent safety factor with a 300kg keel.

In slow-time, we plan to remove the winch, file down the excessive welds, and re-paint the drum parts.
Thankfully, we spotted the damage before the cable failed catastrophically. However, we now feel that it would be prudent to replace the cable every 3 years even if there is no apparent deterioration visible.

When we bought Indianna we gleaned from previous PSSA forum posts that this design of winch has another well-known point of failure; i.e. that the drum can progressively seize on its axle until the original D-shape location in the side plate becomes rounded and the axle turns in the casing. There is a well-publicised mod for the problem but we are hoping that, by regular inspection and application of aerosol-grease to the ends of the axle, we can lubricate the axle sufficiently to stop the drum seizing on it. It was only because we have been inspecting and greasing this area every few months or so that we noticed the cable damage.

In conclusion, these winches are definitely not a fit-and-forget item!

Paul Gray
P275 Indianna
Ken Surplice
2020-12-08T15:37:53Z
HI Paul,
Good update, thank you. My keel rope is dyneema without the outer sleeve. I will share how that behaves over time, even if I am unable to check the sleeve for damage as there isn't one.
Cheers-Ken
Ken Surplice
philip linsell
2020-12-17T17:13:12Z
Hi
Just a thought to upset you dyneema/electric winch users; could the dyneema be bringing more salt water to the drum than the wire did, so increasing the corrosion problems?
I also use dyneema, but on the 26 it just goes through a few blocks on the cabin top!
Philip Linsell
rascal 26
Paul Gray
2020-12-17T18:49:34Z
Good thought Philip but we understand that dyneema is hydrophobic so hopefully would only bring a small amount of 'surface water' onto the drum from the lower part of the rope. Shouldn't therefore be any worse than the wire equivalent???

Regards,
Paul
P275 Indianna
2021-02-20T22:56:36Z
Although we don't have electric winches on my P235, I have done some work on a couple of these winches where the drum has seized on the main spindle and I would definitely endorse Paul's advice to regularly spray this area with aerosol grease, which will hopefully work it's way in to lubricate the drum, once it's seized it is a big job to free it.

Generally I think the winch is well engineered and it is surprising that this vulnerable area was not provided with proper bearings, and so gives the winch a bad reputation.

Another important point I would like to mention is that the electric motor on these winches is very powerful, so it is important to stop the winch before the keel reaches the top of it's travel and doesn't just stall the motor as this puts a great strain on the cable, whether s/steel or dyneema. Now the original manual says there is an overload protection in the switch but has this been incorporated in the switches on our boats? In any case it is rarely necessary to raise the keel right to the top and even when drying out it is good practice to leave a bit of keel projecting to help prevent mud and pebbles being forced up into the box.

Most boats have a tell-tale of some sort, to show the position of the keel, and this should be watched carefully when retracting the keel, and not just relying on a change of note from the winch motor stalling.

Peter (Zephyr)
Phill
2021-02-23T09:34:37Z
I am a committed convert to Dyneema but would offer this cautionary tale regarding the power of the motor. I initially installed 8mm Dyneema with a core and separate cover. Over time, with repeated passing over the pulleys the Dyneema cover wrinkled up to the point where it jammed in the pulley block above the keel. Despite having the overload protection fitted, the winch motor then proceeded to snap the Dyneema! I now use 8mm Dyneema core.

Regarding the old chestnut of the drum seizing on the axle. I would consider that to lubricate the drum reliably the axle would need to be removed, inspected, lubricated and refitted at least annually. This is not too difficult and would only take an hour or so.

I appreciate that I have got a bit boring about this but the modifications that I carried out on my winch about five years ago have proved to be 100% reliable and are not difficult to replicate (see my post 'Keel Winch Modification').

Phill
Phill
2021-02-23T09:36:59Z
  Winch Modification.docx (1,042kb) downloaded 14 time(s).

Some photos of the modified winch.