Wing keel vs fin keel

[NormanS]

Wing keels are far better than fin keels. -- at catching creel (pot) lines.

 

[DJE]

One practical point to watch is that the underside of the wings becomes an important surface for the generation of lift to windward when heeled. But anti-fouling this surface and keeping it clean can be very difficult with some designs.

 

[TSB240]

Wing keels are far better than fin keels. -- at catching creel (pot) lines.

I must be doing something wrong as I have never fouled a line with my pot catcher.?

Is your opinion formed from statistically valid evidence or bar room banter?
Should I be concerned as I take part in the annual Welsh pot dodging slalom championship through Bardsey Sound this afternoon.

 

[[2574]]

Many thanks all, particularly Laminar Flow, for very helpful feedback. It assists the boat buying process considerably.

 

[Graham376]

Wing keels are far better than fin keels. -- at catching creel (pot) lines.

I also wonder whether a careened wing keel boat would float or fill with water when tide comes back, due to increased heel.

 

[[2574]]

I also wonder whether a careened wing keel boat would float or fill with water when tide comes back, due to increased heel.

Not a worry for me as I start to panic in less than 10m as generally, in Scotland, it’s either 100m or zero metres - and not much in between.....

 

[DJE]

I also wonder whether a careened wing keel boat would float or fill with water when tide comes back, due to increased heel.

Doesn't seem to be a problem.

 

[Laminar Flow]

I also wonder whether a careened wing keel boat would float or fill with water when tide comes back, due to increased heel.

It is a possibility. Deeper twin keel designs might suffer that fate if they fell all the way over. Many traditional, narrow designs are subject to down flooding. From personal experience: a Folk boat will not come back up if dried out on her bilges.

 

[Graham376]

Doesn't seem to be a problem.

Do you have a relevant photo of a boat refloated after being careened?

 

[Stemar]

Doesn't seem to be a problem.

I was waiting for someone to post that

One possible disadvantage that I don't think has been mentioned is the stress imposed when refloating if you dry out in deep mud.

If it's a problem, it would preclude the use of my club pontoon, where deep fins dry out quite happily, floating on the mud. Yes floating is the right word. I made the mistake of taking the log impeller out at low water once. I won't be doing it again...

 

[TLouth7]

Aircraft design has developed into putting fins on wingtips to eliminate tip turbulence and improve lift, perhaps there's a connection.

Aircraft do this because they have limits on their wingspan in order to fit into terminal gates. Winglets are always higher drag than if the equivalent area was added to the end of the wing.

In the same way, the area of a keel wing would be more efficient if it was simply used to extend the keel, with the added disadvantage that you need wings on both sides of a keel, unlike an aircraft.

 

[flaming]

If you run aground in a wing keel I have found the best draft reducing method to be to take the dinghy and anything else heavy but easily portable, and all the crew, to the bow. This often has the effect of reducing the draft.

 

[Sharky34]

If you run aground in a wing keel I have found the best draft reducing method to be to take the dinghy and anything else heavy but easily portable, and all the crew, to the bow. This often has the effect of reducing the draft.

How?
Draft doesn't reduce, all that happens, is the bow may tip forward, with boat still attached to the bottom, which may allow reverse to pull it off, much like a bilge keel.

 

[flaming]

How?
Draft doesn't reduce, all that happens, is the bow may tip forward, with boat still attached to the bottom, which may allow reverse to pull it off, much like a bilge keel.

On a lot of wing keel boats draft does reduce. Especially if the leading edge of the keel is a little bit shallower than the trailing edge, which is often the case.

Certainly used to work well on the wing keeled Legend 336 that my Dad had a while back.

 

[Sharky34]

On a lot of wing keel boats draft does reduce. Especially if the leading edge of the keel is a little bit shallower than the trailing edge, which is often the case.

Certainly used to work well on the wing keeled Legend 336 that my Dad had a while back.

It changes the point of contact with the bottom, but can't see how it reduces draft.
Might also make leading edge dig in further.

 

[flaming]

Might also make leading edge dig in further.

Only if the centre of buoyancy is significantly further aft than the keel, which would be rare...

Like I said, it worked and became our SOP for getting off the mud.

 

[TSB240]

If you run aground in a wing keel I have found the best draft reducing method to be to take the dinghy and anything else heavy but easily portable, and all the crew, to the bow. This often has the effect of reducing the draft.

Yep it works.
Chucking the heaviest in the race crew over the side and getting them to push also works in less than 1.5m of water and is much quicker!?

 

[flaming]

Yep it works.
Chucking the heaviest in the race crew over the side and getting them to push also works in less than 1.5m of water and is much quicker!?

Ah, with a 2m keel and being the only crew member over 6 foot tall, I'm not keen to suggest that one.

I prefer not hitting the bottom these days....

 

[Frogmogman]

Aircraft design has developed into putting fins on wingtips to eliminate tip turbulence and improve lift, perhaps there's a connection.

Aircraft do this because they have limits on their wingspan in order to fit into terminal gates. Winglets are always higher drag than if the equivalent area was added to the end of the wing.

In the same way, the area of a keel wing would be more efficient if it was simply used to extend the keel, with the added disadvantage that you need wings on both sides of a keel, unlike an aircraft.

Hmmm. Catalina's version of this is closer to my understanding of the reason for vertical winglets at the wingtips of modern aircraft.

If I may quote to you from an abstract in an article in the International Journal of Naval Architecture and Ocean Engineering

"The endplate causes a blockage effect on the flow, and an additional viscous effect especially near the endplate. These combined effects of the endplate significantly reduce the magnitudes of the velocities under the lower surface of the wing, thereby enhancing aerodynamic performance in terms of the force coefficients. The maximum lift-to-drag ratio of a wing with an endplate is increased 46% compared to that of wing without an endplate at the lowest clearance. The tip vortex of a wing-with-endplate (WWE) moved laterally to a greater extent than that of a wing-without-endplate (WOE). This causes a decrease in the induced drag, resulting in a reduction in the total drag."

 

[dom]

Hmmm. Catalina's version of this is closer to my understanding of the reason for vertical winglets at the wingtips of modern aircraft.

If I may quote to you from an abstract in an article in the International Journal of Naval Architecture and Ocean Engineering

"The endplate causes a blockage effect on the flow, and an additional viscous effect especially near the endplate. These combined effects of the endplate significantly reduce the magnitudes of the velocities under the lower surface of the wing, thereby enhancing aerodynamic performance in terms of the force coefficients. The maximum lift-to-drag ratio of a wing with an endplate is increased 46% compared to that of wing without an endplate at the lowest clearance. The tip vortex of a wing-with-endplate (WWE) moved laterally to a greater extent than that of a wing-without-endplate (WOE). This causes a decrease in the induced drag, resulting in a reduction in the total drag."

The yellow duck seems to be the forum expert on this type of question.

Wld be interesting to hear his thoughts.