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Old 12-03-2016, 22:36   #16
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Re: Twin v. Single Keels

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I think all boats are designed for a purpose and a locale. If I were cruising in northern latitudes where there were shallows and big tidal flows, I'd probably look for a boat with bilge keels so I could do this without spilling my coffee or Sheep Dip:
I can see that being a huge advantage too not having to get a haul-out to look at your bottom sides, or having to dive on it to clean it.
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Old 12-03-2016, 23:20   #17
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Re: Twin v. Single Keels

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So, twitn keel or Catamaran that is the question?
If I were to switch to a cruising multi-hull, it would be a trimaran. There used to be one called a Ama 35 which I thought looked good many years ago.. don't know how many actually ended up getting built. A quick google and I don't find any, but the Dragonfly 35 looks nice, I'm sure it's pricey.

oops, found it... yeah it has been a few years...
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Old 12-03-2016, 23:22   #18
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Re: Twin v. Single Keels

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If I were to switch to a cruising multi-hull, it would be a trimaran. There used to be one called a Ama 35 which I thought looked good many years ago.. don't know how many actually ended up getting built. A quick google and I don't find any, but the Dragonfly 35 looks nice, I'm sure it's pricey.
Why a trimaran?
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Old 12-03-2016, 23:37   #19
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Re: Twin v. Single Keels

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Why a trimaran?
As opposed to cats? OK so this is coming from someone who only sailed Hobie Cats as a teenager, but to me tris just made more sense in terms of safety and use of space. The main hull is the living space like a mono-hull, the location of the rudder and the auxilliary, and as long as the space between the main hull and amas is open and air is allowed to pass through, there is less chance of air getting under there and trying to capsize it. I defer to all multihullers for a critique of my reasoning though. I still really like that Ama 35 design though as a compromise between cruising space and speed.
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Old 27-03-2016, 12:46   #20
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Re: Twin v. Single Keels

Twin Keeler's are slower and don't point into the wind as much as single keels do, I myself have owned both and I'm not in a hurry to buy another bilge. Also the handling is slower and less responsive in a bilge. Imho.
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Old 27-03-2016, 14:40   #21
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Re: Twin v. Single Keels

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Twin Keeler's are slower and don't point into the wind as much as single keels do, I myself have owned both and I'm not in a hurry to buy another bilge. Also the handling is slower and less responsive in a bilge. Imho.
Welcome here, and BTW I had not seen a Van de Stadt 34 Legend before: very nice design! Great size and she looks like she sails very well!
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Old 27-03-2016, 16:43   #22
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pirate Re: Twin v. Single Keels

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Originally Posted by nzyotti View Post
Twin Keeler's are slower and don't point into the wind as much as single keels do, I myself have owned both and I'm not in a hurry to buy another bilge. Also the handling is slower and less responsive in a bilge. Imho.
Some are crap.. however that's a design fault by lazy designers.. others that have more thought applied are quite speedy and can give their fin sisters a run for their money off the wind.. Westerlies, Hurleys, Sadlers etc.. as a cruiser they have benefits that more than compensate.
But that's just my0.000000005 centimes
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Old 27-03-2016, 18:32   #23
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Re: Twin v. Single Keels

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Originally Posted by nzyotti View Post
Twin Keeler's are slower and don't point into the wind as much as single keels do, I myself have owned both and I'm not in a hurry to buy another bilge. Also the handling is slower and less responsive in a bilge. Imho.
Not all twin keels are equal. It seems you have owned one that was not a good sailing boat. Some will point better upwind than most older designs and as well as some new designs, depending on the draft. For the same draft (if that is not a really deep one) a twin keel can be designed to perform at least as well.

I bet this one points well:


Lerouge, the designer explains why some think that a twin keel boat is a pig upwind:
"Bilge keels have unfortunately often been fitted to poor hull shapes, which spoiled their reputation. However a VPP study proved that this solution promised a good potential provided that the keels had decent aspect-ratio and that their tip were optimized to reduce induced drag and interference.
....
After designing several bilge keelers with bulbs whose handling was quite good, the opportunity to go further arised.
One of our clients commissioned us to convert his 36' ULDB with over 7' draft into a cruiser able to dry out without losing her sparkling performance!
After many different appendages tested in a VPP, twin winged keels obtained the best result, the LEROUGE Twin Keel System was born.

Ballast weight was slightly increased to keep the same stability although draft was reduced by 2' 6" and a small increase of wetted surface area had to be supported.
Performance prediction was similar windward performance in a breeze and less speed of the wind in light weather, which was easily cured by an increase of the fully battened mainsail.
Test sails proved the calculations. Steering seemed even improve in strong winds with the reduced heeling arm of the keels.
Drying out was obviously very stable.

Delighted by these results on a boat, which was never designed for such a small draft, we decided to continue our work.
The results are even more interesting on our hull shapes designed from the start for shoal draft with good low angle stability.
Our VPP simulations showed that there is a limit of draft under which performance are rapidly lost.
These same VPP even proves that a Twin Keel System is faster that a single keeler of similar draft!"
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Old 27-03-2016, 19:08   #24
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Re: Twin v. Single Keels

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Some are crap.. however that's a design fault by lazy designers.. others that have more thought applied are quite speedy and can give their fin sisters a run for their money off the wind.. Westerlies, Hurleys, Sadlers etc.. as a cruiser they have benefits that more than compensate.
But that's just my0.000000005 centimes
Quite agree, in fact if you were to sail two identical yachts I doubt you would be able to tell the difference unless you were racing around a circuit. Blown out sails would have a bigger impact, as would crew experience.

In big tidal areas like PNW, NW Europe they offer some real advantages, Less so for the OP if he sails the US great lakes unless shallow draft helps. For us they are definitely a boon.
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Old 28-03-2016, 19:03   #25
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Re: Twin v. Single Keels

Around 2000, Sailing Today tested two Hunter 290s, named Legend 290 in Britain and manufactured in England, , one with fin keel and another with twin keels. The final review that the performance was essentially the same and the only real difference was the helmsman ability. Design had progressed that far. I think the biggest complaint was that the twin keel model's rudder was too long compared to the keels but was manufactured with the bottom being a break away section.

http://www.yachtworld.com/boats/2002...United-Kingdom
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