Jump to content

Retractable Keel Locking Mechanism

Recommended Posts

Ok may have mentioned this earlier but my 830 was originally designed for and sailed in Lake Taupo.

Apparently this required it to built with a ballasted retractable keel/centerboard ala Ross780.

Fast forward to the refit and it has had a new set of foils made, with a bulbed reasonable draft keel. The bulb is a permanent fixture, and the bottom of the trunk/case was made around the foil. It appears to be a carbon/graphite type arrangement. This was then fitted to the boat and an outer case formed to take it to the cabin top.

Therefore, unlike other boats I have seen, the keel needs to be fitted from underneath, not dropped in the top. This means it can't have a tapered top that would lock it tight once fully down.

The shaped/strengthened trunk comes up to bench height, above that seems fairly light.

Lifting mechanism will be rope/block/cabintop winch.

Bulb weight 450-480kg I am told.


I am looking for ideas on how to fit a positive stop to the top of the keel that will ensure the weight is taken off the lifting mechanism when fully down, I'm not too worried about side to side as it is a very snug fit in the case as you will see in the pics but possibly some kind of tapered wedge on the sides could be advantageous.


All I want is keeler type performance with trailer sailer like abilities when it comes to Weiti river entrances, handy to shore moorings and the best anchoring spots in the Gulf - surely it's not too much to ask?








Link to post
Share on other sites

Go have a look at a Noelex 30 /Farr 940 same idea. I cannot remember how it was done, but the keel on mine seemed to lock down pretty well - felt it move when sailing. It could also be locked up or down with a "grid pin" - a large SS pin through the keel and case. Apparently strong enough to support the whole boat on a conventional keeler cradle.

Link to post
Share on other sites

Hi Nigel, on the T750 it was also loaded up from the bottom but then had UHWMPE wedges screwed on that located the top of the keel when down - mated up with similar wedges on the inside of the case. Originally had a plate & four wingnuts to lock down, but this had ended up with a dyneema lashing. I'll see if I can find a photo.

Link to post
Share on other sites

A decent sized dynex strop spliced to the right length to something bolted across the top of the case was what I had on Energy the E7.4. 


In theory the case and the umpwe guides and shims are a pretty close fit but invariably in certain sea conditions (usually upwind) you can get an annoying and disconcerting slop as the fin moves ever so slightly in a fore and aft swinging motion. I ended up putting some e-glass pads in two places either side of the fin on the outside of the case just above waterline and thru bolting it with 2 x M16 SS bolts.


It only took another minute to unlock with two spanners and  not only locked against the sides of the holes but only a little tension took up the slack on the shims inside. Was solid as.

Link to post
Share on other sites

Funlover, Many of the boat sailed out of Fremantle in WA have this type of lifting keel and the two I sailed both had 2 x large horizontal pins that were pushed through the case and top part of the keel when it was down, locking it in place. And yes some water came in, but not much. Actually the positive fixing is required by the rules so it can not retract during a severe knockdown. To hold it up a webbing strop could be attached once it was fully raised (the head came out of the deck into a sort of house) but often wasn't, they just relied on the hydraulics to hold it up.


Cheers tb

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...