Parker 275 - New Keel Hoist.
Prompted by the failure of my second Dutton Lainson electric winch, the desire of the owner of another P275 at our club to replace his Dutton Lainson manual winch, and the interest of Peter Copsey, the owner of a Parker 27 at the club, who has a specialist metal machining company, I developed some ideas I had for a hydraulic keel hoist to replace the Dutton Lainson electric winch.
The completed hoist has just been successfully tested on my boat, and the second system will be installed on the other boat as she completes her current refit.
The hoist uses a hydraulic ram to extend a 4 part purchase, the tail of which is attached to the keel. This means that the 390mm stroke of the ram will raise the keel from fully extended to retracted. The line used is 8mm Dyneema.
I did the design using 3D CAD software, from which Peter Copsey was able to machine the fittings that carry the sheaves, hold the ram, and secure the assembly to the front of the keel box. These parts are made in a marine aluminium alloy, and following the successful test they have been hard-anodised. The hydraulic power unit is a standard unit from a firm called Fluidlink, and the hydraulic ram was made by a local hydraulics company, Atom Hydraulics.
There are some photographs and video of the new hoist here, together with some of the old Dutton Lainson electric winch for comparison:-
https://www.dropbox.com/...hKggF0-0qXN0dLK90ma?dl=0 My apologies for the tractor being parked nearby while I took the external video!
The new hoist intrudes much less into the fo’c’sle than the Dutton Lainson winch. It should also need less maintenance, and should eliminate the issue with the lower wraps on the winch drum having the outer wraps pull through them.
The hoist raises the keel in about a minute, and lowers it in about half a minute. I have incorporated a limit switch, so that the keel will stop before it runs into the top of the keel box, the switch is also adjustable to compensate for any stretch or creep in the Dyneema.
I’ll be sorting out a casing around the hoist in due course.
If anyone is interested in further details, please get in touch.
Dick Garside
P275 No 36 - Dark Star