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post #31 of 99 Old 07-31-2019
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Re: What Kind of a Keel do you Have

Just as a further point of reference, this is a Karma, a recent Mills design.
Heeled Mills Design-E

I think you can visualize how narrow, symmetrical and low wetted surface the submerged hull would be even at this small heel angle. (BTW for the record, I am not a big fan of the current crop of wide beam boats.)


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post #32 of 99 Old 07-31-2019
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Re: What Kind of a Keel do you Have

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Originally Posted by Arcb View Post
Thats sailing upwind I am thinking you like her a bit flatter when running?

I think you are right though. We aren't really talking about the same thing. I am talking about strictly hull form, but with your boat its almost impossible to contemplate your boat without the context of a keel. Its part of the package.

I am thinking more along the lines of maybe a Michael Storer design where the hull itself can be reallistically considered without any board/keel what soever. Long, narrow, hard chines, and very much a modern design.
Two separate topics, the first had to do with a boat being squirrelly when sailing down wind. I chose the two photos of the boat with a pinched stern and a boat with a wider stern to illustrate why a boat with a pinched stern would be squirrelly due to the shape of its water plane as it rolled from side to side. I thought that the pictures sailing upwind would be the best way to illustrate the shape of the water plane in a way that would make it easier to visualize the change in shape as the boat rolled.

Topic 2: I am a big fan of Michael Storer's Viola 14 design with the batwing rig. I have no use for lug rigs. In my mind they offer no useful advantages and come with a real problem of excitation rolling downwind.

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post #33 of 99 Old 07-31-2019
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Re: What Kind of a Keel do you Have

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Off topic, but what the hell is the guy with the pole doing?!?!

Catalina 22
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Re: What Kind of a Keel do you Have

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Off topic, but what the hell is the guy with the pole doing?!?!
He is flossing the rudder. (Cleaning weed off the rudder) It was standard operating procedure before boats started coming with kelp cutters.

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post #35 of 99 Old 07-31-2019 Thread Starter
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Re: What Kind of a Keel do you Have

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Off topic, but what the hell is the guy with the pole doing?!?!
First mate dropped the Grey Poupon.
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post #36 of 99 Old 07-31-2019
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Re: What Kind of a Keel do you Have

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Some multi hulls can feel like they are tracking on rails. Multiple, long skinny hulls provide for much of the directional stability.
Actually, catamaran sterns are quite fat in relation to the hull form - many are at maximum beam. And not all of them are "skinny" - a Lagoon 400 has a hull BWL equal to our previous Columbia 40, but with a much fatter stern than the C40. The L400 tracks and behaves much better down wind than the narrow stern C40.

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Re: What Kind of a Keel do you Have

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He is flossing the rudder. (Cleaning weed off the rudder) It was standard operating procedure before boats started coming with kelp cutters.

Jeff
It looks like the rudder is against its stops and completely stalled. How is that boat even moving forward?

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post #38 of 99 Old 07-31-2019 Thread Starter
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Re: What Kind of a Keel do you Have

Right, skinny sterns, mileage may vary

Heres a clip of mine sailing down wind. Narrow stern by most definitions. Boats overall beam to length ratio is about .29 vs .32 for an Alberg 22 or .35 for a Catalina 22 vs .39 for a First 21. So narrow, but fundamentally different than the pinched stern above. Plus its rounded.

Back to the keel question. This boat uses 2 unballasted bilge boards, which are basically off centre fibre glass centre boards. I attribute much of her handling characteristics to the many options available with the boards. Both about 2\3 of the way up works nicely on a run.

I realise there are no waves in this clip, but this is typical of her downwind performance. Pretty solid. Two situations she can get squirlly in. Too much sail or too much weight on board. But normally she jus kind of skips along. She is double reefed in this clip (kids on board).

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Re: What Kind of a Keel do you Have

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Originally Posted by colemj View Post
- many are at maximum beam. And not all of them are "skinny"
Sure, no doubt there is more than one way to skin a Cat My Catamaran hulls are skinny at the stern. About 4 inches.

She she has no boards, and tracks pretty straight provided she isn't over canvassed.

Disregard the trailing line


Last edited by Arcb; 07-31-2019 at 10:04 PM.
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post #40 of 99 Old 07-31-2019
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Re: What Kind of a Keel do you Have

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Originally Posted by aeaston View Post
I have just a basic fin and a skeg hung rudder.

My dream is a Southerly with a lifting keel. The ability to explore with one of those would be smashing.
My Clearwater 35 has a weighted swing keel, like the Southerlys, but it also has a swing rudder. With the “landing gear” retracted, as shown in the thumbnail, the draft is 2 ft. With the keel down, the draft is 6 ft and the rudder draft is about 3’ 10”.

This boat has inboard shrouds, allowing tighter genoa sheeting angles, and with the elliptical keel, she goes to weather with the best of them. This boat is not tender, due to form stability, weight discipline in the design, and 5000 lbs of lead ballast. Half of the ballast is glassed into the slack bilge and the other half is encapsulated in the leading edge of the keel.

The headroom under the coach roof is 6’3”, but the keel trunk goes all the way up to the coach roof, splitting the main cabin.

So, there are some compromises in the design—primarily in the location and size of the keel trunk, but the advantages of variable, shoal draft are downright addictive. Harbors are larger, shortcuts are available, and gunkholing options are greater than with the traditional 35 footers.
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