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Possibly very different keel hydraulics (Read 354 times)
Fredster
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Possibly very different keel hydraulics
12.04.2022 at 18:25:36
 
Now my attention is starting to come round to the keel hydraulics.
Something I have no experience with at all.
At the moment I see no raised locking mechanism to rake the strain off the piston and valves etc.
itís going to be different to what you all have as but I expect the principles are the same. In this setup the piston contracts to pull on a heavy steel cable running over a block (just under the cabin table) and down a stainless steel tube to the keel housing. There the strap must be attached to the keel. Itís attached very high up the keel but I have not seen where so I donít know the distance between the purchase point and the pivot point. I donít know the load values involved.
My questions I donít think can be answered but I hope that by asking I might learn enough to know how to proceed next.

How many pumps of the handle are needed to raise your keels?
What sort of maintenance is needed for the hydraulic system and how often?
Can the piston sit for extended time (weeks or months) in a loaded state?
What else do I need to figure out about such a system? Possibly, what questions do I need to ask a hydraulics expert?

And thanks for what input you have time for.
https://pin.it/4FqNwus
https://pin.it/PUC7W9G


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Paul
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Re: Possibly very different keel hydraulics
Reply #1 - 12.04.2022 at 21:12:38
 
We all have a steel pin 15 to 18 mm which holds keel in raised position. Ours goes thro the central keel casing and a hole in the keel.

Any loss of hydraulic pressure allows pin to retain keel in up position.
Have you a hole in your plate case? It would seem logical.

I would assume the lift wire attaches to rear side of keel not too far from pivot so cable doesn't go below hull.

I think Nautibuoy needs around 60 full pumps but theis will depend on size / make of pump. If engine in well pump arm limited so quite a bit more..

Within the harbour we often sail with keel part lowered in shallow areas and it doesn't cause hydraulic problems.

I always keep the pressure on as it maintains lubrication of seals. You may find a little loss of pressure over time but this is often a sign that you need a small oil top up.

The hydraulics will be very simple and parts available via any hydraulic engineer. I expect yours is like ours based on lorry cab tilt set up.

Occasionally you may need to replace the seal in the pump which is straightforward and cheap to buy.

Good idea to check wire rope is in good condition . As we have a pin if wire †breaks keel will drop but will come up when tide goes out and we can put pin in to retain in up position while repairs carried out. Only used this once when pump seal failed 15 yrs ago

Paul
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Fredster
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Re: Possibly very different keel hydraulics
Reply #2 - 12.04.2022 at 21:41:40
 
Thanks Paul.
After reading that Iím a little less concerned. I will work on a locking system. As far as I can see it will probably require a wedge going from some sort of pin at the cable eye / piston arm end and then up to the underside of the sheave housing just above.
Iíll also be looking for a way to put the mainsheet in there as a manual backup too.
Then there is the electric option I have seen others mention. One thing at a time.
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Jonathan
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Re: Possibly very different keel hydraulics
Reply #3 - 13.04.2022 at 16:58:53
 
Hi Fred,

I cannot help thinking there must be some means of locking the keel in the raised position but it sounds as if it must be well hidden. At least I now understand why the cable doe not show on a simple diagram I have of the 250 - it does not emerge from the hull.

The pump mechanism is pretty reliable - in my case also about 55-60 pumps once the load is on. Depending on age it might pay to check the state of the hydraulic hose and certainly the cable if you do not know how old it is.
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Fredster
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Re: Possibly very different keel hydraulics
Reply #4 - 15.04.2022 at 00:40:06
 
Hi Jonathan,
From what I have gathered so far, there are fixed keel versions of our boats. The T250. Is that what you have a diagram of?  
All the others have ďdagger boardĒ type lifting keels, except one single exception. As far as I can tell ours is the only swing keel one built. If itís a diagram of this one then please do share.
And yes. It seems strange that there is no retaining pin for the fully up position.
I have reached out to the original owner to enquire about it. I may not be a priority, which I fully understand, so I might not hear back.
Something will be figured out.
I have also been thinking about using a bottle jack as an emergency keel lifter if hydraulics fail.
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Jonathan
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Re: Possibly very different keel hydraulics
Reply #5 - 15.04.2022 at 14:27:31
 
Hi Fred,

This link https://ibb.co/qpT0QY1 will take you to the diagram I have. Actually it is for the TS250s but I guess the s simply denotes swing keel. I inherited this with some papers and brochures when I bought the boat. Goodness knows how many were actually made. You may well be right that yours is the only one. Somewhere on the old forum it was stated that only about 40 boats in total were built and the 250 was an attempt to improve the appeal of the accommodation to partners who may be less interested in performance. Maybe you have to actually sail one to realise  what thoroughbreds they are - race horses - not for pulling milk floats. See some of Alam Lambton's  old comments.
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Fredster
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Re: Possibly very different keel hydraulics
Reply #6 - 15.04.2022 at 20:58:24
 
Ahh yes. I know the image. I picked it up from here possibly a year ago. Most likely from you I expect. So, thanks on both counts.
As I understand it, the TS in the naming is to signify Trailer Sailor. Though really they must be right at the top end of the Trailer Sailor size in terms of classical Trailer Sailing practicality. †The T could be for Trapper too !

Models I know of:
TS240 - Trailer Sailor with vertical lifting keel. (Initial copy of the starflash hull)
TS250 - Trailer Sailor with vertical lifting keel and a larger coach roof than the TS240. (This one, interestingly, is not listed on Sailboat Data so I possibly have this one wrong!! )
T250 †- †same as the TS250 but with a fixed keel so even more useable cabin space. Not quite a trailer sailor either. †
T250S - Same as the TS250 but with a swing keel. (Sometimes I see it written as TS250S and sometimes itís written as T250S. Though itís not written about much at all) Like the T250, it enjoys the extra cabin space since the keel stays outside the hull. The minimum draft is an extra 25cm deeper than the vertical lifting counterparts. Apparently it sails reasonably well with a raised keel too. It still has the same keel area in the water, just converted into a long keel. I donít know if the extra draft disqualifies it from being a trailer sailor. Either way the trailer needs to accommodate the keel.

There is at least one TS250 or TS240 in the area here. Iím not sure where Tis went to! Anyway it will be interesting to compare and see how the keel differences change the sailing characteristics.
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« Last Edit: 15.04.2022 at 21:05:50 by Fredster »  
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