To bilge keel or not to.

[Pete7]

I have owned fin and bilge keel. The phrase, horses for courses does count- even if Chay Blyth tried to sail a bilge keeler around the world in the Golden Globe - he turned back of course - but went on to achieve a lot in other areas of sailing.

He did make it to Capetown, not bad in a 30ft yacht.

I commented on the other thread that I couldn't notice the difference between our bilge keel yacht and a week spent on a fin keeled charter yacht.

Memsahib and I both like exploring and creek crawling, so bilge keels for us.

Keyhaven quay, a lovely spot with a very friendly YC we regularly stop at.

For Pete, if your regular cruising destination is the Scottish Western Isles, then I could see bilge keels being useful for many of the small drying harbours and beaches up there. Moody made a series of 33, 34, 35 and 36ft yachts over the years with bilge keels in a number of different styles from stern cockpit to centre cockpit and pilot house etc.

 

[Pete7]

It's said the aerofoil shape of keels provides lift.

Can see that working for an aeroplane wing where it can be asymmetrical, so the top surface shape pulls upwards more than then bottom shape pulls downwards. But a boat keel is symmetrical or it would only work well on one tack. So how does that work?

With twin keels we have an 'upper' keel and a 'lower' keel, so we're back to asymmetry and we can play with splaying and toeing in, to maybe equal or beat fins?

I believe but might be wrong, that a modern aerofoil keel is sailed slightly offset which creates a pressure difference and therefore lift to windward. This is only a few degrees but enough. I think most of us have some minor weather helm going to windward so the rudder is slightly to leeward to maintain a course. Does this cause the keel to also be slightly offset? Happy to be corrected.

Our keels are aerofoil shaped. Are they symmetric? not sure I need to carefully measure them at some point.

Pete

 

[RogerJolly]

I believe but might be wrong, that a modern aerofoil keel is sailed slightly offset which creates a pressure difference and therefore lift to windward. This is only a few degrees but enough. I think most of us have some minor weather helm going to windward so the rudder is slightly to leeward to maintain a course. Does this cause the keel to also be slightly offset? Happy to be corrected.

Our keels are aerofoil shaped. Are they symmetric? not sure I need to carefully measure them at some point.

Pete

Ah, yes. Was being a bit simplistic there Pete7. Must be some sort of slight 'angle of attack' caused by sail's pressure.

 

[MisterBaxter]

I think a fin keel is said to have lift because the boat is actually moving at a slight diagonal through the water due to leeway, so the keel has a small angle of incidence, like an oar being slid sideways through the water while twisted a tiny bit. The foil shape of the keel minimises turbulence while moving at various different angles of incidence.
With bilge keels, I've never been clear on the forces involved when a bilge keel boat with splayed, assymetric keels is sailing well heeled. Does the leeward keel provide any lift? I suppose the net of the lift from both keels is always downwards, so when the boat is heeled there's a slight lift to windward?

 

[Frogmogman]

As mentioned by others, RM make some pretty fine twin keelers (I hesitate to call the high aspect ratio bulbed fins that the use “bilge keels”).

I have been delighted with my lift keel Sun Odyssey 349. It draws 1.25m with the keel up, making it easy to sneak in and out of the many ports around where I sail in Brittany a doddle, and 2,55m with it down, giving it excellent upwind performance. It will happily dry out on its beaching legs, although I don’t know that I would want to leave it on a drying mooring on a permanent basis.

The sailing performance and displacement are identical to the deep keel version (as tested by a German yachting magazine).

 

[Aja]

He did make it to Capetown, not bad in a 30ft yacht.

I commented on the other thread that I couldn't notice the difference between our bilge keel yacht and a week spent on a fin keeled charter yacht.

Memsahib and I both like exploring and creek crawling, so bilge keels for us.

Keyhaven quay, a lovely spot with a very friendly YC we regularly stop at.

For Pete, if your regular cruising destination is the Scottish Western Isles, then I could see bilge keels being useful for many of the small drying harbours and beaches up there. Moody made a series of 33, 34, 35 and 36ft yachts over the years with bilge keels in a number of different styles from stern cockpit to centre cockpit and pilot house etc.

I do remember one Moody 346 on the west coast. Called Elizabeth 'A' she was for sale for a while at Largs and eventually went elsewhere, suspect to the English east coast.

As far as I'm aware, people don't go creek or ditch crawling here in the west coast. You're either sailing or you have hit a rock

 

[Bodach na mara]

My current boat has twin keels because it was the last Westerly Seahawk on the market when I was looking for one. I don't need bilge keels and didn't really want them but I now don't mind them. Particularly when it comes to laying up. Where I get lifted out single keel boats must have the mast removed where twin keel boats don't. This saves me a considerable amount every year.
But I do hate applying the antifouling between the keels.

 

[Supertramp]

You need to get the opinions of people sailing twin keel boats and happy with them. I have sailed a lot in twin keel Westerlies but not as large as you are considering. The later Fulmar sails very well, and holds its own with similar size fin cruisers. There is some "slap" between windward keel and hull in small seas/fresh wind. The earlier Westerlies were less lively, didn't point very well but were capable. They sailed downwind with less rolling than fin keel boats. They allowed access to shallow anchorages but in practice drying out was rarely done. Touching the bottom at LW without worry was more common.

Gsailor at #20 says it well - you will probably hardly notice the difference unless racing competitively but it might open up new harbours and anchorages.

 

[justanothersailboat]

The whole "bilge vs fin keel" "debate" seems a bit daft to me. You either mostly do the kind of sailing where they help, in which case you need one; or you do the kind of sailing where you don't mind a deeper draft in return for performance, in which case you probably don't want one; or you do kinds of sailing where it doesn't make much difference in which case buy either based on other criteria, unless a bilge keeler works for you logistically, in which case buy one. I suspect a lot of people are in the "doesn't make much difference" category really.

As a creek crawling East Coast non racer, mine points well enough for me; it's enough that I can sail where I want to go and don't feel the need to motor upwind like some seem to. I wouldn't trade her for a deep fin unless I became rich enough to move to a Solent marina or west of that and also had flexible enough work and old enough kids to sail for months rather than days at a time. That's not looking likely! Maybe bilge keelers being so well optimised as "working family's coastal weekender" doesn't do their image any good?

 

[B27]

The whole "bilge vs fin keel" "debate" seems a bit daft to me. You either mostly do the kind of sailing where they help, in which case you need one; or you do the kind of sailing where you don't mind a deeper draft in return for performance, in which case you probably don't want one; or you do kinds of sailing where it doesn't make much difference in which case buy either based on other criteria, unless a bilge keeler works for you logistically, in which case buy one. I suspect a lot of people are in the "doesn't make much difference" category really.

As a creek crawling East Coast non racer, mine points well enough for me; it's enough that I can sail where I want to go and don't feel the need to motor upwind like some seem to. I wouldn't trade her for a deep fin unless I became rich enough to move to a Solent marina or west of that and also had flexible enough work and old enough kids to sail for months rather than days at a time. That's not looking likely! Maybe bilge keelers being so well optimised as "working family's coastal weekender" doesn't do their image any good?

I'm sure I'm not alone in looking around at moorings etc and thinking, ' I could get a fin keel boat, keep it there and it will cost me x, or a bilge keel boat and keep it somewhere else at a cost of y.
Or I could get a trimaran keep it somewhere suitable etc etc.
Then I weighed up what sailing I'd do in either case, convenience factors and the package as a whole.
If I'd plumped for the fin option, I'd probably do a different mix of sailing.
Actually there are variations of bilge and fin, because going smaller or bigger would change the mooring options and the mix of sailing I'd do. I could have bought a bigger boat but that would mean keeping it further away, or a smaller boat and kept it further up the river and joined a different club.

I might one day want to change the mix of sailing I do, then I might change type of boat. Or just go bigger or smaller?
I also sail other people's boats and do some dinghy racing.

 

[Pete7]

unless I became rich enough to move to a Solent marina or west of that and also had flexible enough work and old enough kids to sail for months rather than days at a time. That's not looking likely!

Until a couple of years ago we were paying £25 a night for 31ft in a marina berth. This year we stopped occasionally in marinas, priced between £36-38 a night. However, much prefer more traditional harbours like Lyme Regis and a new one for us, West Bay averaging £23 a night. Or going all the way up the Dart and Salcombe estuaries and drying out.

 

[RogerJolly]

We pulled into Lyme Regis once, plumped for the plastic floating pontoons. Went right up to the shore end to avoid the bouncy walking.

Woke up in middle of night wondering why we were dead still. Tide had gone out leaving us sat on our bilge keels hard aground with the mooring ropes bar taught. Managed to untie and reset ourselves no problem.

We'd never thought to check the depth - shallows at shore end of pontoon (landsmen's expectation to be coddled with warning notices everywhere).

Not sure what would have happened with a fin...

 

[jwilson]

In some places like the Bristol Channel where I spent many years sailing, bilge/twin keelers are by far the most versatile option: anything else including many centreboarders are dubious for some little but quite interesting little harbours. (Porlock/Lynmouth/Ilfracombe/Clovelly/Instow etc on the S coast and many of the nicer little harbours in Pembrokeshire Solva/Saundersfoot/Tenby/etc round to Porth Gain and up into Cardigan Bay).

On the East coast there seems to be from my limited experience of the area actually more soft muddy bits where you can use a not too deep fin-keeler.

Now I have a deep fin keel based in Falmouth, and even there I occasionally think that twin keels would be nice - though deep and efficient ones! On the west coast of Scotland you may as well have a deep fin keel.

 

[James_Calvert]

We pulled into Lyme Regis once, plumped for the plastic floating pontoons. Went right up to the shore end to avoid the bouncy walking.

Woke up in middle of night wondering why we were dead still. Tide had gone out

Not sure what would have happened with a fin...

To answer your question, we have a fin. We touched bottom and heeled over a bit on one occasion. The bottom was hard sand. There was more of it than there should have been. Dredging for the summer season hadn't happened that year.

I'd realised we would probably touch and stayed up just in case.

The following morning I checked around with a sounding stick. Not much difference in depth further in on that occasion.

 

[doug748]

Until a couple of years ago we were paying £25 a night for 31ft in a marina berth. This year we stopped occasionally in marinas, priced between £36-38 a night. However, much prefer more traditional harbours like Lyme Regis and a new one for us, West Bay averaging £23 a night. Or going all the way up the Dart and Salcombe estuaries and drying out.

Sounds great. You could spend a summer in France and spend very little on moorings, some of these places you could sit out a hurricane in safety and not spend a penny except on wine. Too late for me but I sometimes have a day dream about it, so to answer the question, right now I might well go for a twin keeler










Surprising that twin keels are not more popular in Northern France.


.

 

[Pete7]

Sounds great. You could spend a summer in France and spend very little on moorings, some of these places you could sit out a hurricane in safety and not spend a penny except on wine. Too late for me but I sometimes have a day dream about it, so to answer the question, right now I might well go for a twin keeler

Surprising that twin keels are not more popular in Northern France.

That's the plan, just need to retire first. Not sure were to go first, Scottish Western Isles, Baltic or Brittany.

 

[Frogmogman]

Surprising that twin keels are not more popular in Northern France.

Oh but they are. Check out any of the drying harbours; they’re full of them.

The Bi-Loup bilge keelers are great little boats, and popular in Brittany. In fact the bi-loup 10.2 which is 33ft, but quite roomy for its size might fit the bill for the O.P.

WRIGHTON BETHUNE 62 SLOOP BI LOUP 102

 

[Tranona]

Sounds great. You could spend a summer in France and spend very little on moorings, some of these places you could sit out a hurricane in safety and not spend a penny except on wine. Too late for me but I sometimes have a day dream about it, so to answer the question, right now I might well go for a twin keeler


Surprising that twin keels are not more popular in Northern France.


.

There are, but not quite in the same way as popular in the UK 30 or 40 years ago. Mainly smaller boats, although Jeanneau made many 25-30/ twin keelers (there is one in our club) before they settled on lift keel boats. Also many long keelers with bilge plates for drying out or legs. Mostly, like here primarily to use moorings in drying harbours rather than regularly drying out just for an overnight stop. Also, just like here by the late 80s boat size started to increase and more and more deep water moorings became available, particularly on the west coast so the attraction of twin keels except for smaller boats declined.

 

[Skellum]

Have you thought of a wing keel? You don’t get the drying out ability, but you do get more shallow draft access. Starlight 35 and Sigma 36/362 were made with them. I’m sure there are others too.

The RM looks an interesting boat.

 

[B27]

Have you thought of a wing keel? You don’t get the drying out ability, but you do get more shallow draft access. Starlight 35 and Sigma 36/362 were made with them. I’m sure there are others too.

The RM looks an interesting boat.

Shallow draft in itself, without the ability to reliably dry out, does not seem to be that much of a benefit when the tidal range is 5 metres.