Why would anyone get a twin keel if they could have a fin?

It's not possible to generalize about the performance of twin keel boats...

It depends on what type of hull they are attached to.., and on the geometry of the keels themselves.

RM are in the position of having built the exact same hull with twin and single keels, so they would have a pretty good idea of the differences. I think that on one of their videos there is a discussion of the performance trade-offs. The ORC website might have ORC certificates for single and twin keeled versions of the same hull - it would be interesting to see what the VPP predicts.

I think that as far as sea motion is concerned.., other things being equal.., a twin keel boat should roll less - greater moment of inertia, so the same effect as the tight rope walker with a pole.
 
fredrussell said:
An interesting article, but if all that is true you have to ask yourself why pretty much all racing boats are fin keel.
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Are they?
Open 60’s (before hydrofoils) had a canting keel and a canard/leeboards either side - one could argue they sailed in a twin keel arrangement.
 
HissyFit said:
Got to totally disagree with you on that one. You might not consider an extra 10 foot as being significant, but as the length increases you get a squared increase in the volume. This is what Isambard Brunel realised when justifying the economics of the Great Britain.
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Actually more like cubed, at least in theory. Since some of the volume is not especially useful, above shoulder height, we could settle for two and a half perhaps.
 
johnalison said:
Actually more like cubed, at least in theory. Since some of the volume is not especially useful, above shoulder height, we could settle for two and a half perhaps.
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Depends how tall you are! As someone 6'4" I really value height (and long bunks!)
 
On the OPs original point of taking a UK bilge keel boat to the Med, IMHO buy a locally popular model locally. The EU paperwork will be in place, there will be a proven track record for the class in local conditions, and local marine engineers will be au fait with it's foibles.
I bought a boat in the UK designed for the Solent and took it to the Northern Aegean, and it wasn't ideal for local conditions there. I had a lot of fun with it for the 10 years I kept it there, but it was more awkward to use than the kind of boats the locals preferred. (the only benefit was that the Greek port officer largely ignored a small British flagged boat with uk vat deemed paid, owned by a brit with all the paperwork and insurance issued by brit authorities and companies, because he assumed that as a brit I largely followed all the rules. A brit boat full time in the Med now can be a liability.)

When I wanted a yacht for the Bristol channel, I bought one that is reasonably common in the Bristol channel, suitable for the big tidal range and drying harbours, and the obvious choice was bilge keels.
 
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DangerousPirate said:
Are there any advantages except for the drying out bit that it can stand up?

It slows the boat down and they don't point so well, they also have a deeper draft. There is a boat close by that looks nice, but it's atwin keel and I am not sure if this boat could be the boat for me. I intend to sail to the meds with it, and live on it, too. So it doesn't have to be a racer, but performance towards windwards might come in handy for longer tacking sessions?

Also I am not sure if Fin Keels are more stable or not thatTwin Keels? Especially at sea.

Boat in question is a Mirage 28, but I am also asking in general because I have seen a few Twin Keelers now.
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my Bruce anchor is far, far better than the anchor on your boat. Discuss.

there. An anchor thread. Enjoy.
 
Maybe I am just overthinking this. The boat seem nice and roomy and comfortable to be in at sea. I won't encounter any major problems due to the twin keels when going to the meds, will I?

I just don't wanna buy a boat that i will regret to have bought later.
 
You would think that a bilge keel would have an advantage when heeled. One keel would assume something like the fin and the heeled fin boat losing grip. But it doesn't seem to work out that way.
 
DangerousPirate said:
Maybe I am just overthinking this. The boat seem nice and roomy and comfortable to be in at sea. I won't encounter any major problems due to the twin keels when going to the meds, will I?

I just don't wanna buy a boat that i will regret to have bought later.
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The only downside I can think of is if you do go aground in the Med , increased heeling will not get you off where the fin keel has possibilities .
 
It doesnt always follow that the bilge keelers are slower than the fin keel counterparts. I havea very distant memory of a PBO investigation in which they sailed 2 Sadler ?25s against each other, on fin one BK. There was not enough difference in performance to say one was the better than the other, except that the Bilge keeler was found to be a little faster off the wind than its fin keeled sister!
 
DangerousPirate said:
Maybe I am just overthinking this. The boat seem nice and roomy and comfortable to be in at sea. I won't encounter any major problems due to the twin keels when going to the meds, will I?

I just don't wanna buy a boat that i will regret to have bought later.
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Yes, you are. The boat is what it is and as I suggested earlier it is almost irrelevant what type of keels it has. It was not designed to live aboard, nor for the type of use you intend simply because that was not common when it was built. Indeed virtually no 28' boats are designed for living aboard so you have to take what is available and adapt it for your use and you are starting with a solid well built boat with reasonable space inside and reasonable sailing ability. In a sense those are a given, but to make the boat a good economical buy for use on a small budget you need to look at the key requirements I listed earlier. It is difficult for those who have never done this sort of thing to appreciate what is in involved and what features of the boat make a difference between success and failure. All 40 odd year old boats will have problem areas - engine, electrics, sails, deck gear or whatever and the knack when buying is to find a boat with the best in these areas. It is making a mistake in assessing the condition of the boat that will be the source of far more regret than the actual model of boat or whether it has one keel or two.
 
LONG_KEELER said:
The only downside I can think of is if you do go aground in the Med , increased heeling will not get you off where the fin keel has possibilities .
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You are in serious trouble if you go aground in the Med! Grounding (except maybe hitting the odd uncharted rock) and shallow water are very unusual. That is one of the reasons why shallow draft and twin keels are never seen except UK boats that the owners have sailed there!
 
Tranona said:
You are in serious trouble if you go aground in the Med! Grounding (except maybe hitting the odd uncharted rock) and shallow water are very unusual. That is one of the reasons why shallow draft and twin keels are never seen except UK boats that the owners have sailed there!
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Surely if you go aground with a twin keeled yacht then unless you were making 12 knots at the time you simply sit there and wait for tide to lift an extra 2 -or 3cm and then pull off, using your spare primary anchor.

But I don't understand this fascination for keel(s) design if you are going to live on the boat.

Tranona has made the case for buying something liveable - especially as you will spend factorially more time (10:1 - 20:1 ?), in a marina or at anchor, than you will ever do sailing. Even when you are sailing 'performance' will be way down your list of priorities as you will have no other yacht against which to compare and it simply does not matter (as a liveabord you will have some creature comforts, toaster, electric kettle and more and more + a couple of spare anchors and a spare rode) - that you would never dream of if your focus was performance.

But if you desire to live as a hermit - go for the poky little yacht - but don't expect any company to be uncomplaining.

Jonathan
 
DangerousPirate said:
Maybe I am just overthinking this. The boat seem nice and roomy and comfortable to be in at sea. I won't encounter any major problems due to the twin keels when going to the meds, will I?

I just don't wanna buy a boat that i will regret to have bought later.
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You certainly are over thinking this. As usual with questions like fin or twin keel, everyones experience is based on their limited number of boats they have sailed upon and in waters that are totally diffenet to the Med. There is virtually no rise and fall of tide, so no way you can use twin keels to dry out with, so discard all this "advice". Virtually every boat will sail to a better or lesser extent, so again keel choice is irrelevant.

You really need to understand some of the advice given to make sure you start again with the criteria that should be your starting point. Condition of the boat and its equipment is very important as this will save you money and time in repairing/upgrading. If you are planning to live aboard, then to minimize costs you will try and anchor most of the time. This means having large enough water tanks and the ability to recharge your large battery bank. Keeping food in a warm climate means some sort of refrigeration, preferable keel cooled for reduced electrical consumption. If you anchor and want to swim, then having a proper bathing ladder is a must to get out of the water. In warm climates then ventilating the cabin helps keep it cooler so that means plenty of hatches and windows that can be opened. Even things like vinyl bunk cushions should be a potential reject. Now think like you are in the Med and see if any boat you view is close to these criteria.

It may be simpler to buy in the Med as the boats are almost already suited for the climate. So instead of taking a lot of time and effort getting from the UK to the Med, you can start enjoying your new lifestyle immediately and save making the mistake of buying the wrong boat.
 
Just to add: a twin keel is not really an ideal ditch crawler for the canals, in spite of shallow(er) draft. In fact the keels, extending some way from the centre line can prevent you going alongside the bank, especially in the smaller canals. Trying to get out of the way of a peniche by scuttling to the side might also be difficult.
 
I miss having twin keels, especially in the mad current climate where getting overnight marina stays has been problematic. (A twin would have opened up lots more possibilities).

My twin keel Hunter Channel 31 was a very fast boat (& arguably comparatively faster than my current 40’). She rolled less downwind and made discernibly less leeway than my current deep fin. Tbf she probably didn’t point quite as high (but not by much) and a modern sail plan with blade jib helped a lot. I certainly wouldn’t be put off having another twin, at least not from a sailing / performance perspective.
 
Neeves said:
Surely if you go aground with a twin keeled yacht then unless you were making 12 knots at the time you simply sit there and wait for tide to lift an extra 2 -or 3cm and then pull off, using your spare primary anchor.
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Not if there is a swell & you tip over the leeward keel you do not. The boat is held at 160 degrees , thus throwing crew overboard, Puts massive strain on the bilge keel etc.
i saw my friend run aground & his boat tripped over. He was fortunate that the boat rotated a bit & a wave picked it up & it went back onto the keels. If the bank had been steeprt he would have been held there. As it was he had hull flex & movement of intrnal cupboards . Plus he had to re build skeg & rudder.
2 other 40ft+ boats that had grounded on the bank ( depth charted was 6 metres) needed lifeboat assistance. He managed to get off once the boat came upright as the swell bounced him. But he was there for a while
 
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