RobbieW
Well-Known Member
My Rival 41 has what I think of as long fin with a skeg hung rudder, dont know of any other name for it
Why are keels on boats so different?
- Thread starter Nostrodamus
- Start date
My Rival 41 has what I think of as long fin with a skeg hung rudder, dont know of any other name for it
Twister_Ken
Well-Known Member
Like several trends I think it started with Sparkman & Stevens, in this case their Clarionet design from 1966.
You can see how the shape derives from the full keel - essentially it is a full keel cut away aft to reduce wetted surface area, then coming back to support the rudder.
RobbieW
Well-Known Member
That looks a bit smooth and folk boaty, the Rival is more like this...
with a keel thats about 1/2 lwl
with a keel thats about 1/2 lwl
LittleSister
Well-Known Member
I would call that arrangment a long fin, like wot my old Hurley 22 had.
Woodlouse
Well-Known Member
You forgot wing keels which are for winning the Americas cup.
AndrewfromFal
Well-Known Member
I spent some time sailing on a GK29 that has been retrofitted with a Wing Keel (of the Warwick Collins Tandem variety). It was a rather wet boat but the way it handled in a steep seaway was impressive; - in terms of the smoothness of the ride, the damping motion of the wings worked splendidly and meant the boat was as comfortable as long-keeler in such conditions. The wings also meant that the boat was very stable downwind, with none of the 'death rolling' normally associated with that sort of 1970s IOR-style hull shape.
I think it's a shame that wing keels went out of fashion so quickly, having seen the benefits first hand.
KellysEye
Well-Known Member
My Rival 41 has what I think of as long fin with a skeg hung rudder, dont know of any other name for it
That's it thank you.
That's it thank you.
jimbaerselman
Well-Known Member
Ok. Try "evolution". Next time you're in an airport, study aircraft wing tips.
They are designed to do the same job as keels - to create a force at right angles to a fluid flow, whilst creating the minimum possible amount of drag. Except airplanes aren't designed to stand on their wing tips.
Concord looked a bit like Ken's S&S keel. Tiger Moth biplanes remind me of bilge keelers. Early wing keels imitated plates on the end of wingtips. Then planes realised that flow was always one way, so they did away with the bottom half of the plate. Now they do a smooth curve upwards at the end, rather than an abrupt right angle. Planes even do ballast - carrying fuel tanks at the wing tip, so the wing doesn't bend too much when the ship's full of fuel.
This evolution matters when performance is the issue. But just think how impractical some keels are. 4m deep, narrow chord, shaped ballast wings at the bottom . . . how few harbours you can enter, the height of lift needed to come ashore.
So you're looking at a spectrum - performance vs practicality. And every buyer is going to make a different judgement. So every seller is going to make a different keel - to match the buyer's whims. And actually it makes b** all difference, since one design racing is far more fun. And when cruising, what matters is pub door to pub door, so your real performance issue is likely to be the speed of your tender. Or the time taken to manouevre into that berth. Close to the pub, club or bar.
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Nostrodamus
Well-Known Member
Jim that is the best explanation of keel design I have heard in a long time. I wonder how many buyers put on their list of desirable options the shape of the keel!
Tranona
Well-Known Member
It certainly was an influencing factor in my recent new boat purchase where there were 4 types of keel available on my short list - with one of the boats having 3 options. The options were Boat 1 deep fin, shallow bulbed fin; Boat 2 deep T shaped keel, shallow bulbed fin; boat 3 deep fin, shallow bulbed fin, long shallow fin with centreboard (and twin rudders!).
Being based in Poole Harbour and enjoying the shallow harbours of the Solent my choice was shallow bulbed - which kept all three boats in the frame, so final decision was on other criteria. One of the advantages of buying new is having this choice whereas buying used can reduce the options depending on what is on the market when you want to buy, so you are stuck with a choice out of other peoples' earlier choices.
harry potter
Well-Known Member
http://forum.woodenboat.com/archive/index.php/t-18934.html
If you want an efficient keel this blog will help.
If you want an efficient keel this blog will help.
[70521]
Well-Known Member
Why are there so many different designs of motor car? You can take a Land Rover round Brands Hatch, but try taking a F1 car over a field.
