Lifting Keel Info

[dennism]

I was looking at some photos recently of a Jeanneau 35 and Beneteau 331 with Lifting keels.

I am interested in understanding how you sail with them. Does the Fin part need to be down when sailing a full rig or is it a matter of trimming it for the situation as one might do if sailing a dingy.

Are there any other posts / threads to read up about them anywhere please, or anyone who could enlignten me. Good bad or otherwise...thanks

 

[roblpm]

Well I don't know much about these specifically but as an owner of a Parker 275 lift keel I know a bit about the principles.

I think the key to your question is determining where the ballast is. In my particular parker most of the ballast is in a ballast plate in the bottom of the boat. So it is safe, and even designed, to sail with the keel up downwind.

Other boats have all the ballast in the keel in which case you need to sail with it down.

The other thing you need to bear in mind (seajet will be along in a minute to back me up) is that you need to maintain the lifting keel which means storing it out of the water with enough height to be able to drop the keel.

I think someone else on here has a Jeanneau SO 35 lift keel so should be able to tell you more.

 

[Seajet]

Lift keel boats of that size usually have a long ballast stub keel with a relatively light centreboard type plate going through it.

One only really needs to lower the plate to get a grip on the water when going to windward.

So do a thorough check on the stifness - stability in a blow, ballast ratio and where is it - and handling ; feel and response to the helm.

Like all lift keelers, have the boat inspected ashore, hanging in slings if necessary, with the keel down; if she doesn't come with high trestles or a cradle to allow keel maintainence, ask yourself and the owner if it has ever been done ?!

 

[Kelpie]

We treat our centreboard pretty much as we would with a dinghy. Early days with the current boat, but I would say there is a noticeable boost in downwind performance by raising it. However it does make the helm awfully heavy when raised.

 

[roblpm]

(seajet will be along in a minute to back me up)

I am psychic!

 

[EdWingfield]

I have a 331. Seajet's on it with the description, although 'relatively light' plate? Mine was disassembled March 2014 for renewal/repair of mechanism by engineers. I couldn't have lifted the plate.

The boat is sailed with plate up until wind comes forward of the beam, then plate is lowered progressively until close-hauled and full plate (2.2m draught)

 

[Seajet]

There is the point that a part raised centreboard moves the Centre Of Lateral Resistance ( CLR ) aft, which can affect handling, usually resulting in less weather - or even lee - helm and sometimes making a boat hard-mouthed, the reason why high performance dinghies like the International 14 have vertically raising daggerboards, to keep the CLR in the same place.

 

[aquaplane]

I have had both a Jaguar 25 and a First 18 with swing keels. It was possible to sail both with the keel up but windward performance suffered as you would expect.

Sailing the First 18 on the Broads through some thin water it felt odd with the keel up, a CLR problem I believe.

My Copland Harrier has all the fixed ballast in a verticaly lifting keel, there is no way I would sail it without the keel fully down and locked in place.

Boats >30' (or 25') are differnt beasts to trail sailers though.

 

[mrming]

I have had both a Jaguar 25 and a First 18 with swing keels. It was possible to sail both with the keel up but windward performance suffered as you would expect.

Sailing the First 18 on the Broads through some thin water it felt odd with the keel up, a CLR problem I believe.

My Copland Harrier has all the fixed ballast in a verticaly lifting keel, there is no way I would sail it without the keel fully down and locked in place.

Boats >30' (or 25') are differnt beasts to trail sailers though.

Swing keels are usually mostly outside the boat whether up or down, so the only reason to raise the keel is to reduce your draught. For example in my swing keel Beneteau 235, there's no benefit to lifting the keel downwind as there's no reduction in drag. I only lift it for creek crawling and for lifting in and out of the water.

 

[Seajet]

mrming,

surely there's slight frontal area resistance and probably more significantly wetted area drag with a swing keel in its lowered position.

 

[mrming]

mrming,

surely there's slight frontal area resistance and probably more significantly wetted area drag with a swing keel in its lowered position.

Hmm. Here's a similar swing keel for reference:

I had just assumed as there was pretty much the same amount of keel outside the boat, the drag must be about the same, but thinking about it, you're right - it would be like swimming with your arm hanging down rather than parallel with the surface.

One other effect of raising the keel is that it brings a lot of weight towards the back of the boat. Could be useful downwind in heavy weather with the kite up but to be honest that's when I'd rather have the keel down in case of a broach.

In lighter winds I get everyone out of the cockpit to get the transom out of the water, so moving weight further back would be bad news.

 

[Seajet]

My boat has a ( near ) vertically lifting keel, but when I sailed fast dinghies the effect of raising the board and changing the CLR was pretty clear, handy on the Osprey but not on the Express Dinghy, worst thing I ever sailed; downwind in a F4-5 the thing went into a death roll and no matter what we frantically tried re board position, we were going over...

The late Bob Salmon reportedly sailed his Anderson 22 most of the way to Antigua with the keel up to reduce drag, the boat is self righting like that but he's a braver man than me.

Once at Poole entrance in the A22 when I'd cocked up the tide and was fighting to get in against the ebb, we were static until we raised the keel, which just allowed us to make progress.

 

[dennism]

Thanks for responses

Sure the thoughts of having a swing keel with the longer length keel / section length bolted to the hull and less mass at the bottom seem to appeal to me. I look at bulb keels and wonder how they stay on with such a small section bolted to the hull and with such a mass at the bottom end, but no doubt they do.

The main point of post I suppose was to find out how lifting keels sail and whether the boat could be sailed fully with the fin up and without tipping over and being able to creek crawl and can dryout (incase I get in the wrong place at the wrong time)

Pros and cons of the lifting keel vs standard? Also do fin keels now come with twin rudders, or what year were the twin rudders were introduced on the J and B boats?

I have never sailed a lifting keel yacht, but quite fancy one...meanwhile as an armchair sailor, don't have any boat, but I enjoy the dreams.

Will try and attach photos of ones I was looking at...

 

[dennism]

photos attached (figured out how) ... Jeanneau 35 and Beneteau 331 - lifting keels

 

[Victoria Sponge]

I've sailed a Beneteau 323 with a lift keel and twin rudders. Having a lift keel is ideal if you want to sail in the Thames Estuary and other areas of the East Coast. There is a trade off though, twin rudders mean no prop wash in reverse and when sailing you need to reef much sooner.

I've also sailed a Beneteau 323 with a deep fin keel. It was much easier to sail and reverse.

Why do you fancy a lift keel?

 

[Seajet]

Dennism,

obviously I'm a believer in my boat's format as anyone is with theirs but I'll try to be objective.

A keel with the ballast bulb on the end makes for a much stiffer, more stable boat than one with internal ballast in the hull, this is a simple matter of leverage, righting moment and common sense.

I've not seen any efficient racing boats without their ballast on the keel end and efficiency usually translates to cruisers.

My particular 22' boat seems to benefit from a hydrodynamic ' end plate ' effect, with the veed ballast bulb keeping waterflow over the keel to give lift to windward.

Such a lift keel is harder engineering work for larger boats, so cruiser designers often go for stub ballast keels - with less righting moment and a light lifting plate going through them - a lot easier for the builders and operators on boats over about 25', it can enable push-button electric keel winches where my full-weight keel with ballast doesn't allow this.

One must also consider the engineering and hassle issues of maintaining the keel plate, which is often hidden by the housing on such a boat.

The only boats I've heard of letting their keels go were wooden swing keel designs where the pivot bolt wore through, apart from the grp Sailfish 18's which seem able to lose their light swing plate.

Personally I'd say once one gets beyond 25' where it's practical or economical to carry the lift keel winches etc, think about twin keels for practicality, getting in and out of marinas with sills or locks,or half tide moorings - so most of the Solent.

Personally having tried them over a few years I wouldn't bother with deep water moorings again, nothing but hassle as I mentioned in a recent thread, so either pleasant sheltered half tide moorings or a marina berth for me.

 

[TSB240]

photos attached (figured out how) ... Jeanneau 35 and Beneteau 331 - lifting keels

View attachment 48637View attachment 48638

A friend has a 343 clipper.

Keel and rudders similar to the 331.
I would describe it as extremely "soft on the wind" and it rocks over alarmingly in the dock with the slightest cross wind. Even with the plate down.

When new it was sold by Dickies to an owner who wanted to keep it on a drying mooring. He ended up with it on a free deep water mooring paid for by Dickies as it would not reliably stand up on its own keels and rudders.

I saw a similar design dry out in Sauzon Harbour .
https://dl.dropboxusercontent.com/u/79352891/IMAG0705.jpg

Mainly shoal draft but a mixture of Biquilles, Shoal and legs and shoal and rudders types....
https://dl.dropboxusercontent.com/u/79352891/IMAG0709.jpg

One fell over! at top left One didnt front right!
https://dl.dropboxusercontent.com/u/79352891/IMAG0710.jpg

My personal opinion is the design is too compromised to be of little benefit in comparison to the disadvantages it gives of a tender,uncomfortable sea motion, Limited shoal draft ability and unpredictable results if drying out.

I would have one of these for my old age!
https://dl.dropboxusercontent.com/u/79352891/IMAG0708.jpg

 

[PhilipH]

I have an OVNI 395 with lifting keel (swing) with nearly 40,000nm and a very good part of that was sailed downwind/wind abaft the beam and with the keel up. This is in winds ranging up to 35kts. The ballast is in the hull. We have found the boat tracks much better downwind with the keel up and stops any rounding up that can occur with the keel down. We have even sailed close-hauled with the keel up but leeway becomes significant and keeping on track problematic. Boat is delightful with the keel up and downwind/wind abaft the beam. Sometimes we only have the keel down when manoeuvring to lower or raise the anchor or when in marinas.