Deep Fin with bulb and wings

[apward]

I'm considering a boat with a deep fin racing keel and bulb. The original design of the keel had wings attached to the bulb, but these have been removed. Why?
What's the advantage of having wings attached to the bulb or I guess disadvantage seeing as they have been removed?

 

[TimBennet]

I'm considering a boat with a deep fin racing keel and bulb. The original design of the keel had wings attached to the bulb, but these have been removed. Why?
What's the advantage of having wings attached to the bulb or I guess disadvantage seeing as they have been removed?

For about 10 years after 1986, you couldn't sell a boat without wings. Everybody wanted them and every boats sprouted them.
Then people realised that often the only 'thing' wings did for a boat was increase the wetted surface area and hence slow the boat down, especially in light airs.

Where 'wings' have worked, it's only been where a racing rule has limited maximum draft and wings have been a rule insensitive addition, but then only after hours of test tank trials.

So, along with mullet hair do's, wings went out of fashion and were given the chop.

 

[Rossynant]

Theoretically wings give a bit better sideforce when heeled, in shallow draft versions were used for this reason; also they act as bulb does, i.e. give possibility to put more weight down there.
Disadvantage is more friction drag on every point of sailing, more important though - they bury in very effectively on grounding, which is a bit inconvenient when somebody ordered this to have smaller draft for some purpose

 

[Tranona]

Are you saying the keel originally had wings or that the design originally had wings but your keel has a bulb instead?

The claimed advantage of wings was that they made the keel more effective by stopping endplate losses of flow, and kept the ballast lower down so that draft could be less but performance not lost compared with a straight deep fin. Idea never really caught on although those who had them seemed to be happy.

 

[bitbaltic]

For about 10 years after 1986, you couldn't sell a boat without wings. Everybody wanted them and every boats sprouted them.
Then people realised that often the only 'thing' wings did for a boat was increase the wetted surface area and hence slow the boat down, especially in light airs.

Where 'wings' have worked, it's only been where a racing rule has limited maximum draft and wings have been a rule insensitive addition, but then only after hours of test tank trials.

So, along with mullet hair do's, wings went out of fashion and were given the chop.

I have a wing keeler and I'd agree with that. They give no performance advantage over a bulb and have a number of drawbacks in comparison.

The only rider I have is that on my boat they are intended to give shoal draft and if the mass of the wings went into a bulb then the draft would be slightly deeper.

If my boat was designed with wings and they had been removed, though, I would be concerned about the effect of that but much more concerned about any other modifications a previous owner felt confident to make.

 

[Resolution]

For about 10 years after 1986, you couldn't sell a boat without wings..

To be extremely pedantic, I think the key date here is 1983 not 1986, and it was all kicked off by Australia finally beating the US to win the America's Cup. To extract from wiki:
"Alan Bond arrived at Newport with Australia II, billed as one of the biggest threats to American dominance of the 12 Metre class. The boat was designed by Ben Lexcen and skippered by John Bertrand. The revolutionary winged keel of the Australian yacht was a subject of controversy from the outset of the challenger series, with the New York Yacht club alleging that the winged keel boat was not a legal 12 Meter, and that the keel design itself was the result of Dutch engineers, and not by Lexcen. This second point would make Australia II illegal under the requirement that the boat be "designed and constructed in country" as the Deed of Gift that governed the competition stipulated. The boat was ruled a legal 12 Meter, and she was allowed to participate in the regatta. The speed of the new contender, along with the controversy and protests intensified international media attention to the series."

 

[Daydream believer]

A chap in our club who has crossed the atlantic quite a few times says the most comfortable ride he had was in a boat with a winged keel. He felt this seemed to help motion.
Do not know if it is correct. Perhaps the " wingers" amongst you would like to comment

 

[bitbaltic]

A chap in our club who has crossed the atlantic quite a few times says the most comfortable ride he had was in a boat with a winged keel. He felt this seemed to help motion.
Do not know if it is correct. Perhaps the " wingers" amongst you would like to comment

Difficult to say I reckon. How do you factor out east-west, west-east and the different conditions on different trips to come to a conclusion about keel configuration that is statistically distinguishable from coincidence?

 

[Phoenix of Hamble]

They also screw up any efforts to get off the putty by heeling the boat over!

 

[TimBennet]

To be extremely pedantic, I think the key date here is 1983 not 1986 . . .

Mea culpa - the mind is going!

 

[fishermantwo]

They also screw up any efforts to get off the putty by heeling the boat over!

Also a bit awkward when slipping and antifouling.

 

[dunedin]

Worth knowing the type of boat as many different type of "wing keels" we're fitted.

Many of the comments here sound like they apply to the more cruiser oriented designs, where a wide wing like keel base was added to a conventional cruiser style fin - typically to lower the centre of gravity and increase "grip" on shallow draft versions.
If the OP is talking about a more race oriented design it could be a narrow chord keel fin, with a torpedo weight on the bottom - and some racers then had narrow chord lightweight wings added to the sides of he torpedo. I am not a naval architect, but suspect removing these winglets would have minimal impact on ballast / righting moment - and may have been dropped to optimise rating, or simply after getting fed up of catching every piece of weed or rope they passed.

Need piccies

 

[apward]

i am talking about a more race oriented design with narrow chord keel fin, with a torpedo weight on the bottom - lightweight wings added to the sides of the torpedo.

it also has a canard fwd of the keel for upwind performance.

 

[dunedin]

i am talking about a more race oriented design with narrow chord keel fin, with a torpedo weight on the bottom - lightweight wings added to the sides of the torpedo.

it also has a canard fwd of the keel for upwind performance.

Yes, thought it might be - though plus canard it must be pretty tasty design, if needing to be sailed carefully. Sounds like racing rules optimisation, but would need a racing design expert to advise properly. Perhaps the rating office could advise when removed

 

[bbg]

i am talking about a more race oriented design with narrow chord keel fin, with a torpedo weight on the bottom - lightweight wings added to the sides of the torpedo.

it also has a canard fwd of the keel for upwind performance.

In that case the wings were there to stop endplate losses as Tranona says. Like the winglets you see on many modern airplanes. Few race boats are designed with them these days, so I suspect they were added when it was fashionable to do so, and removed because it was found they didn't improve performance.

 

[Sybarite]

In that case the wings were there to stop endplate losses as Tranona says. Like the winglets you see on many modern airplanes. Few race boats are designed with them these days, so I suspect they were added when it was fashionable to do so, and removed because it was found they didn't improve performance.

I always thought that they were potentially dangerous in the case of drying out. If the ground weren't level there might be a situation of initial stability followed by a much more severe falling over. Also if the boat were on its side it would risk being much further over ie the mast virtually horizontal.

 

[bbg]

I always thought that they were potentially dangerous in the case of drying out. If the ground weren't level there might be a situation of initial stability followed by a much more severe falling over. Also if the boat were on its side it would risk being much further over ie the mast virtually horizontal.

I suspect the wing in the OP's case were tiny. Virtually no structural integrity and no ballast. Purely hydrodynamic.

I agree with you for the cruising-type wings, though.