Wing Keel vs Fin Keel . . . Confused . . .

[bob perry]

Wings to be effective have to have aspect ratio just like keels. Short, thick stubby wings may get the VCG down but they do very little for lift and drag. You can't fix a short stubby keel with short stubby wings.

Don is correct. I would warn against lumping all "wing keels" into one category. There are good wing keels and there are nad wing keels.

[ozskipper]

No one mentioned added the righting moment. Assuming the wing is an attatchment to and existing keel.

[Julie Mor]

Originally Posted by Cotemar

Velma,

Depends on where you live. In shallow water areas, sailors love Wing Keels.
If you have deep water around your area go for the Fin Keel.

Mark

Mark, in that first picture of the winged keel you posted, the wings are located aft on the keel. Ericson's winged keels have the wings forward. I know it probably makes no difference now but the original Ben Lexcen wings were located forward.

Does anyone know which location is more effective in producing a better sail-ability?

[thomm225]

The Wing Keel on production boats like the newer Catalina 30 and the Ericsons are for the advantage of a shallow draft. They will not point better than the deeper keel boats and are probably less stable.

On the Americas Cup racing boats however, the wing is added to the deep keel. The keel wasn't shortened at all. This is why the Australian Boat (with deep winged keel) in 1983 kicked the crap out of the US boat (deep keel no wing) and Dennis Conner to take the Cup which the US had held onto for like 130 plus years.

Also, lots of weight was added to the wing which was great since it was located near the bottom of an already deep keel.

I said they kicked the crap out of the US boat, but it was actually a bit closer than that due to mistakes:

http://www.youtube.com/watch?v=t-L3L_3dyOE

[jrbogie]

Originally Posted by Jim Cate

I have to agree with Paul L: in otherwise similar boats offered with either keel t ype, the deeper fin is faster to windward. Been proven repeatedly.

I suspect that the outbreak of wing keel designs in production boats stemmed from all the publicity given to Ben Lexen's successful America's Cup boat which had the first widely seen wing keel. Its success stemmed not so much from its inherent superiority but from the intricacies of the International Rule that rated the 12 Metre class which gave it an advantage over all.

To gather another perspective, if wing keels were faster, all new race boats would tend to have them. What we see is deep "strut and bulb" type fins, either fixed or canting. Obviously, such designs have disadvantages for cruising boats.

Cheers,

Jim

what he said.

[Suijin]

As others have pointed out, "winged keels", on production cruising boats, are exclusively a means of distributing more ballast as low as possible on a shallow draft boat. They don't have any performance benefit at all and will not go to weather much less anywhere else as well as a deeper draft straight fin keel.

But the advantage is obviously a shallower draft, and for some that can be a real benefit. Just yesterday a Farr 55 that had been sitting at the dock was hauled and I was shocked to see that she drew only 6' with a massive wing keel. So that boat draws the same as I do, which is pretty impressive given how large she was. It's all about how you use your boat, where you go, and what your priorities are.

[Polux]

Originally Posted by Paul L

I don't know where you are getting that wing keels go to weather better. Most wing keels are in place to reduce the draft of a deep fin keel. The boat is often offered with both options. Deep fin keel or shallow(er) draft wing keel. If you look at the PHRF rating for the two, the deep fin will be rated significantly faster. You can't beat a deep draft with shallow appendages when going hard on the wind. In my mind the advantage of a wing keel is the shallow draft. Since most cruising sailing is done off the wind, the wing will be as fast as the deeper keel version on the same boat. The disadvantage is they are often shaped like a bruce anchor and will be harder to get off in a soft grounding. Like anything else on a boat, it is just one of the trade-offs you have to accept.

Paul L
svjeorgia.blogspot.com

I believe you both are right. Probably the poster that said that a wing keel had a superior upwind performance was referring to swallow keels with the same draft, one a wing, the other a fin.

Off course you are right in what you say between a comparison between a deep draft keel and a swallow wing keel.

There was a time that even deep keel performance boats made experiences with wing keels (even on America's cup) but in the end, if the draft is big enough it seems not to bring an advantage, at least not with canting keel boats.

[belizesailor]

Originally Posted by s/v Moondancer

Unicorn is right about the advantage going to windward. However I used to own a wing keel boat and when she was aground getting her off was very difficult...

When aground you can get keel boats off by heeling them by pulling laterally/diagonally on the main halyard from another boat, a dinghy can do this because of the large lever arm, and reducing the effective draft and then motoring off or having another boat pull you.

Just putting all the sails up and getting the boat to heel will often make the difference.

When you try and heel a wing keel the draft increases so the only way off is a lot of power going forwards or backwards.

I am told they get deep draft boats over the Rio Dulce river bar by heeling and towing.

Wing keels are a poor choice for a cruising boat in the Bahamas.

Yes, we used to call wing keels "reverse danforths" because they can anchor a boat by the keel quite effectively. And limit the effectiveness of most of the traditional techniques for getting a mono off the bottom. [emoji30]

The wing keel designs for modern cruising boats have little to do with the original...which was a deep draft wing. It was designed to improve performance and did. Current cruising wings were designed to reduce draft and improve sales...which they did. At the cost of some performance...particularly to windward in moderate to heavy conditions.

[belizesailor]

Originally Posted by Unicorn Dreams

...

DISADVANTAGE Stay out of shallow water, not to sure how the wings would hold up to touching as they appendages sticking out to the sides of the keel and if a wave causes the boat to heel over at that time major damage.

This is just a personal opinion....

Most modern wings are plenty strong to handle normal loads. Though in theory would provide more twisting leverage if caught on the tip of a wing. The lever arm for a typical dead ahead grounding should be less due to reduced draft.

I used to work in a charter fleet that had some wing keels and raced in a fleet that had many. Ive not seen it be a problem and dont know of any hard data that exists.

[belizesailor]

Originally Posted by s/v Moondancer

...

I am told they get deep draft boats over the Rio Dulce river bar by heeling and towing.

...

Deep draft boats on the Rio (and many other places) are assisted by heeling them under tow. On the Rio, local fishng boats are usually enlisted to do this by taking a halyard.

Controlling depth over the bar is about 6' if on the correct course (regardless of what you may hear). So, a boat has to have significant draft to need a tilt. But I know of a few 7-8 drafts that have crossed the bar with assistance. One who decided to buy land on the Rio because it was too much trouble to get back out (partially in jest I think).

[belizesailor]

Originally Posted by Rex Delay

I have also had the anchor rode wrap a wing keel in the middle of a dark and stormy night. Took hours to sort it out. A wrapped rode will not hang up and a fin keel.

Yah, done that too...great fun!

[belizesailor]

Originally Posted by Paul L

I don't know where you are getting that wing keels go to weather better. Most wing keels are in place to reduce the draft of a deep fin keel. The boat is often offered with both options. Deep fin keel or shallow(er) draft wing keel. If you look at the PHRF rating for the two, the deep fin will be rated significantly faster. You can't beat a deep draft with shallow appendages when going hard on the wind. In my mind the advantage of a wing keel is the shallow draft. Since most cruising sailing is done off the wind, the wing will be as fast as the deeper keel version on the same boat. The disadvantage is they are often shaped like a bruce anchor and will be harder to get off in a soft grounding. Like anything else on a boat, it is just one of the trade-offs you have to accept.

Paul L
svjeorgia.blogspot.com

+1.

Current cruising boat wing keels have little to do with the original design. The orginal was on a deep draft keel and designed to improve performance...which it did. Cruising boat wings were designed to reduce draft and improve sales...which they did.

Take the same boats (with diff keel options) to windward in moderate to heavy conditions and the deep fin will noticeably out perform the shoal wing. The wing keel version will have significantly more leeway.

[UNCIVILIZED]

With some winged keels, the difference in performance vs. a standard fin isn't nearly as big as lot of folks think. Depends on the keel design. But ballpark, on a production boat you're looking at 10sec/mile (or less) vs. a standard keel. AKA less than the difference between a good, & a poor finish on the boat's bottom.

Part of this is due to the fact that winged keels can be designed to maximize the end plate effect, thus increasing the efficency of the fin section above the wings. So basically they trick the water into "thinking" that the keel is deeper than it really is.

The other design perk which comes with them is that they can be drawn so that the number & size of the vortices coming off of the keel are reduced. Which means less drag, & thus, better performance.

The next time you're traveling, take a look at some of the aircraft & see what's on the tips of their wings

[robert sailor]

Originally Posted by UNCIVILIZED

With some winged keels, the difference in performance vs. a standard fin isn't as big as lot of folks think. Depends on the keel design. But ballpark, on a production boat you're looking at 10sec/mile (or less) vs. a standard keel. AKA less than the difference between a good, & a poor finish on the boat's bottom.

Part of this is due to the fact that winged keels can be designed to maximize the end plate effect, thus increasing the efficency of the fin section above the wings. So basically they trick the water into "thinking" that the keel is deeper than it really is.

The other design perk which comes with them is that they can be drawn so that the number & size of the vortices coming off of the keel are reduced. Which means less drag, & thus, better performance.

The next time you're traveling, take a look at some of the aircraft & see what's on the tips of their wings

Yes aircraft wing tips can be designed to reduce the vortices caused by the high pressure meeting the low pressure at the wing tips and yes by doing so you do decrease the drag and increase the effective span but it hardly has the same effect at 6 knots as at 400 knots. A bulb keel with a flat bottom will be just as effective as 95% of the wing keels. In the end nothing beats draft when sailing to windward.

[UNCIVILIZED]

Originally Posted by robert sailor

Yes aircraft wing tips can be designed to reduce the vortices caused by the high pressure meeting the low pressure at the wing tips and yes by doing so you do decrease the drag and increase the effective span but it hardly has the same effect at 6 knots as at 400 knots. A bulb keel with a flat bottom will be just as effective as 95% of the wing keels. In the end nothing beats draft when sailing to windward.

We didn't routinely reshape the wings on the IACC boats' keels because it was fun to pour molten lead

And if my earlier posted figures on speed differences don't seem right, have a look for yourself via the racing handicaps of various boats. Where the rating in seconds/mile can be directly compared on a particular boat having the 2 types of keels. PHRF New England - Handicapping - Base Handicaps