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Sailboat Diaries: Keel Conundrums

05/31/2017 12:46 PM

Sailboats utilize an underwater wing to prevent side slipping (literally being blown sideways) when sailing on a beam reach (perpendicular to the wind).

Small sailboats are typically given a centerboard and daggerboards. Larger and heavier boats are supplied with keels. My boat's keel is a retractable keel, providing a boat draft range of 9 in. to 4 ft. Made out of steel and with a large, bulbous ballast on the end, it pushes 350 lb.

Raising and lowering the keel is done via a wire rope connected to a ratchet winch in the cockpit. The wire crosses a standing block before being routed into the boat cabin and into the keel trunk.

The trunk houses the keel inside the boat and keeps it from view. Inside is a double tackle configuration, with the lower blocks attached to the keel wing via thick, stainless steel brackets.

Issue #1: Pulleys and cable replacement

The current 3/16 in. wire and 3 in. pulleys are rusting badly. I plan to replace all of these. The wire rope will be attached to an overhead bolt via a loop. (Point A in the picture).

I plan to use a thimble on the wire, but how should I reconnect the wire to make a loop? With a U-clamp or with a swage sleeve?

Issue #2: Splash-proof lubricant

The keel rests in wooden guides, located fore and after along the keel edge inside the trunk. Obviously this is a potential big source of friction.

The wood is currently rot free, likely due to the healthy quantity of yellow-brown and slightly sticky lubricating grease present in the grooves (point B in the picture).

I'd like to supplement or replace this lubricant with a splash-proof lubricant to help keep this area trouble-free--any recommendations?

Issue #3: Keel limiting mechanism

At the base of the keel trunk, there used to be a keel limiter bolt. Its job was to prevent the keel from extending below the boat (and thus becoming ineffective and potentially dangerous). It's former estimated location is point X in the second picture.

A previous owner removed this bolt, likely because it leaked somewhat. That owner also epoxied over this area and made marks along the wire rope to prevent extending the keel too far.

However, there was not a mechanical way to prevent the keel from dropping out below the boat, and I'd really like to implement one in case a friend is helping me do it one day.

Some ideas:

  • Size the wire rope to the maximum extension of the keel. This would eliminate extra windings around the ratchet winch.
    • Or install a sleeve on the wire rope that prevents a point in the wire from going through the first block, with the same purpose.
  • Reinstall a limiter bolt. However, I don't really know what I'm drilling into here. All I have for reference is pictures on the internet.
  • Install a wire rope leash. An extra line measured to size that prevents the keel from dropping too far. One click back on the ratchet winch would take the weight off the leash and back onto the pulleys.

This is the issue I need help with the most. How do I prevent the keel from extending beyond it's maximum 4 ft. extension?

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#1

Re: Sailboat Diaries: Keel Conundrums

05/31/2017 1:59 PM

1). Either or both will do the job. Question is do you have a crimper to set the sleeve.

Notice that there was only one clamp on the wire double them up. All so tape up the end so it doesn't untwist. Also a bit of safety there. That tape does not hurt anywhere as much as the sharp ends of the wire.

2). A Marine Grease its water proof.

3). Leash or replace the bolt. If the line would break or come undone then you have to go fishing for the keel. And getting 350 lbs up from say 30 feet of water will not be fun.

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#7
In reply to #1

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 9:51 AM

There are actually two U clamps on the current wire. The one has just rusted to blend in with the wood behind it. (It you look closely you can see it.)

I don't have a swager on hand, so I'd prefer to use some U clamps.

I'm leaning towards adding a leash or two. Part 2 of the keel project addresses a small leak where the limiter bolt used to be. I've found evidence that the keel was grounded at some point, damaging the bolt and its location in the fiberglass trunk. I'm going to need to fiberglass over this area soon.

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#11
In reply to #7

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 1:39 PM

I did look closely and see what you are refering to. It looks like the head of a bolt used for what appears to be an upper limit stop.

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#2

Re: Sailboat Diaries: Keel Conundrums

05/31/2017 2:47 PM

Well the obvious question, at least to me, is what type of seas you plan to encounter, and do you plan to sail in fresh or salt water, as this will dictate the materials and heartiness of the design required....I always used a rigger for any type of wire or rope connecting, they are specialists...When making any changes to the design it's best to have a boat builder to consult with....the steel cables have been replaced with ultra high strength synthetic line...

http://forums.iboats.com/Fiberglass-Boat-Repair/

http://forums.iboats.com/Boat-Building-Repair/

http://www.seawardyachts.com/retractable-keel-sailboats-how-they-work/

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#8
In reply to #2

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 9:56 AM

It's probably going to be 90% inland lakes, 10% coastal sailing (nothing open or blue water).

For the shrouds and stays I'd definitely have a pro rigger do that. But they're in good shape. This is a unique fix, I'm a solid 100 miles from a real sailboat yard, and I feel good about replacing a cable and some pulleys.

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#3

Re: Sailboat Diaries: Keel Conundrums

05/31/2017 3:10 PM

3.) Add an extra stainless steel bracket (or two) which will engage with the top of the waterproof keel housing at "C".

The housing may need to be reinforced with another bit of stainless steel.

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#6
In reply to #3

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 9:46 AM

Unfortunately this won't do. C in your picture is the top of the lower fiberglass trunk panel. The upper part is removable and sits flush with the rest of the trunk. It provides access to the blocks picture for servicing/replacement.

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#4

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 3:46 AM

If you're looking for a total rebuild

You could come at it from the the concept of a drawer(cutting board) use nylon and/or ball bearings for the edges to slide on, and you can use a motor or hand crank screw push with nylon pusher for up and down.

With switchs for eletronics stops top and bottom and thread stops for hand opperations.

Use a course thread rod and nylon pusher for a rapid deploy and recovery and flip flop switching.

Use a fine thread rod and nylon pusher for custom keel adjustments burst mode switch.

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#5

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 4:36 AM

Whatever you do... keep it simple and "takedownable" (yes that really is a word honest )
On no account use electrics or electronics... recipe for endless trouble.
Gravity is very reliable for getting it down and a "mandraulic" system for getting it back up is fine.
Del

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#9
In reply to #5

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 9:59 AM

Installed a manual bilge for just this reason!

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#10

Re: Sailboat Diaries: Keel Conundrums

06/01/2017 12:11 PM

#1 For starters, switch to stainless steel cable and fittings. I would swage myself, however, there are wedge lock type fittings available that have a tapered bore and wedge that locks tighter as the cable is pulled. they are reliable and don't require the swaging tool. Personally I hate U-bolts. They just add a stress riser.

#2 It's likely that the guides are lignum vitae or ironwood, which is a self lubricating hardwood commonly used in propeller shaft strut bearings and prop shaft packing glands in the old days. I would suggest you consider replacing the guides with UHMW plastic or fitting UHMW liners as they are very slippery and don't require any lubrication. There are legal issues with putting lubricants into water. I volunteer with the steamship Portland and we are severely limited in the lubricants we are allowed to use where the lubricants can end up in the water. I would suggest you avoid guide lubricant as much as possible.

#3 Use a stainless steel bolt, install a plastic or sheet metal cover over both ends and pot the cover full of silicon rubber RTV caulk. No leaks and lasts forever, but removable when necessary with a rotary wire brush.

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