Lifting Keels

[EssexAnne]

Have a question regarding the basics of lifting keels in a yacht

Is the lifting keel compartment always flooded with seawater?

How is dampness avoided in that lifting keel compartment and throughout the boat?

 

[Daverw]

On ours, kelt 29, the water level is the same as hull water line, not sure what you mean dampness as it’s no different to the rest of the hull. The keel box forms the saloon table base and is covered by headlining. Never seen and condensation on it.

 

[Kelpie]

There are several different ways of designing a lifting keel.
In our Deb 33, the keel pivots and fits in to a slot in a stub keel. Nothing protrudes above saloon sole level and nothing is open to the cabin so there is no damp.

 

[RichardS]

As mentioned, the sea-level line anywhere that is connected to the sea is always exactly the same everywhere throughout the boat. Provided that the cables/levers/rod for lifting the keel are sensibly designed, there should be no additional dampness in the cabin.

Richard

 

[Seajet]

My lift keel casing is open at the forward upper section but doesn't have anything to do with damp - it's fresh water like condensation one has to worry about for damp.

 

[Lon nan Gruagach]

On the only one I have seen the top edge of the compartment is above sea level, which is well defined even when heeling. The top cover (perspex for some strange reason) is sealed to the rest, so no chance of damp from that. The lifting rope exits to the deck without being exposed to cabin air, so again no chance of damp.

 

[DownWest]

Difference between lifting keel e.g. A22, and pivoting centre plate., like the Deb? Most plates are in sealed boxes and lifting in trunks with open tops that can be closed, or even go to cabin top level.

 

[Seajet]

Agreed, there are pro's and cons' to each, a plate will kick up if hitting anything but a vertically lifting keel won't - the Anderson has a large tufnol crash pad in the aft edge of the keelcase to prevent the tapered keel cheesewiring into the hull in a really hard impact.

Generally pivoted plates are lighter, sometimes working through a slot in a fixed ballast stub under the hull, as in Seal 28, Anderson 26 etc.

A vertical lift keel can have a ballast bulb on the end where it's much more effective - but engineering this above about 25' becomes difficult.

Vertical lift keeps the CLR Centre of Lateral Resistance in the same position longitudinally re the hull ; with a pivot plate it shifts aft as the plate is raised.

Pivot bolts and corresponding holes in plates wear oval in time due to wave action at the mooring / berth, easy or very hard to work on depending on the design.

What none of them do is contribute to damp in the cabin !

That's a fresh water problem due to condensation and / or window - hatch leaks etc, and if the furnishings get salt water from waterproofs or spray they'll forever attract damp.

 

[ProDave]

The lift keel boat we used to own, had a lead encapsulated keel that pivoted at the front and lifted up into a keel box that formed the base of the table.

The keel box was moulded in GRP as an integral part of the hull and yes it fills with water up to the water level but just like any other bit of the hull, the moulding keeps the water out.

It was lifted with a stainless steel rope that exited the top of the keel box and you pulled on in via a nut on a lead screw with a winch handle, 50 turns from up to down.

You could unbolt the table top to get access into the top of the keel box for inspection and servicing.

There seem to be as many variations on a "lifting keel" as there are lifting keel boats.

 

[Seajet]

ProDave,

I'm pretty sure the Seal 22 has a similar arrangement, I think the Seal 28 too; a good idea to have a removable plate on top of the keelcase to inspect the works.

The Anderson 22 vertical lifting keel ( 950 lbs with a large ballast bulb on the end, 2-4'6" draft ) is lifted by a braked trailer winch via a galvanised wire to a sheave at the internal deckhead.

I just have to undo a couple of screws to get at the works of the simple winch.

Some boats I've heard of ( I won't name but let's say French, quite modern ) have pivot bolts and mounts glassed in and inaccessible, a real pain for owners when the pivot pins or mounts wear.

 

[ProDave]

I never did actually see the pivot mechanism in mine. I fear like you suggest it was a pin through the front of the keel box and glassed in as there was nothing visible.

 

[AEMD]

I've had three lift keel boats, the Evolution 19 had a vertical lft keel on a cable worked with a Tirfor jockey winch in the forward cabin - we replaced the cable a couple of times and the actual winch too. The winch was a bit of a pain hung as it was over the forward berth.
This boat also had an A shaped frame which could be fitted inside the keel box once the keel was down using a weighty stainless steel rod with a bolt that passed through a hole in the top of the keel casing and the A 'frame' to very firmly lock the keel down and immobilise it tok so it didn't clunk around. Great little boat, very fast too.
Another was a lift keel Newbridge Venturer, they are quite rare. This boat had a substantial stub keel with a pivoting plate. The pivot bolt itself was easily accessible with the boat off the water, a very substantial stainless bolt run through the forward edge of the keel stub. When I got the boat, which had been badly neglected, I anticipated all sorts of problems with this, but the 20 year old bolt was in perfect condition, the nut undid easily and it never presented a problem. The original drop plate was very rusty and beyond rescue, but replacement was dead simple, just a sheet of steel the Rutland Sailing Club bosun cut for me for £20 !
The trailing edge of the plate had a hole to which was attached a stainless chain which passed through the hull in a glassed tube with I think a pulley inside at a point where there was an elbow bend. This exited via a keyhole slot at the forward edge of the cabin sole. You just pulled the chain and stoppered it in the keyhole slot. I got a tiny bit of leakage around where I think the pulley was, well above the waterline, easily repaired. Again, a clever system and a boat which sailed really well despite the reputation for being a 'caravan'.
Reluctantly we decided we needed a boat we could stand up in, so now have a Leisure 23SL, a good boat but a bit of a worry with bilge keels on a lake with very shallow areas.