Bow Wing

[Andrew Evans]

The Vendee Globe boat "Ocean Planet" added a bow wing to stop the boat from diving when surfing. Look at the photo at: http://tinyurl.com/86d3g
Bruce said it worked very well.

I'm considering doing the same thing on my Olson 30 before sailing to Hawaii. Does anyone have experience with this, or just comments?

Andy Evans
Foolish Muse
Victoria, Canada.

[dougfrolich]

Trade the olsen in for a moore24 and you wont need the wing, and you wont crash either. but if you want wings, check this...

[usa2]

the wings on AAPT/Grundig are there to prevent lazy spinnaker sheets from getting sucked under the boat during gybes.

[Andy P]

Int moths used bow wings ~ 1970 ? in early UK Magnum designs.
But when nosediving, the extra drag of the wing caused more pitchpoling instead of less. The wing angle had to be set high ( and therefore high drag in most situations of a moderate nosedive) , because if the angle of the dive was greater than the angle of the wing - the wing force was down = superfast pitchpole.
The 1990's and later moths use the foil on the rudder ( T foil ) which is self regulating, and very efficient.

[mistral]

pitchpoling is a sudden and impulsive process. Once that you have entered into it, you have a great inertia to deal with, i don't think a violent pitchpoling could be stopped by some dozens of lbs. of displacement placed in bow wings.
May it would be wiser to trim the boat to avoid nosediving.
Inertial water ballast at the stern: have you consiedered them??

fair wind
Mistral

[yokebutt]

Concur with Doug, the Olson 30 is certainly a fast boat, but not forgiving enough to be a really effective singlehander. Don't get me wrong, I know at least two guys that have done the SHTP with them, but the Moore is a lot better behaved near the edge, and the power is much easier to modulate without having to crawl up on the foredeck.

Yoke.

[D'ARTOIS]

It is just a sprayrail of some kind. No effect in heavy seas whatsoever, more a gimmick than a uasable item.....

[gonzo]

Added-on foils and other appendages are usually an indication of poor design. It is a fix for an unforseen or badly calculated problem.

[Doug Lord]

Thats a pretty broad statement with the evidence of how well "foils and other appendages" work on real boats. Like the t-foil on the(pre-foiler) Moth and Biekers version of a T-foil on an I14. The banana boards on Patient Lady and the same on the Orma 60 Tri's. The fixed wings on IACC boats and the fixed wings on Andy Dovells canting keel boats used to generate lateral resistance. Not to mention the foils on all out foilers like the Moth, Rave and Hobie trifoiler.
I think "foils and other appendages" are in the early stages of applications in both mono's and multies to allow changes in hull design, righting moment and/or wetted surface impossible without them. In my opinion, there is a bright future for all sorts of variations on this theme as an intrinsic part of sailboat design....

[cyclops]

As a non racer, and reading all the statements. It is obvious you surface sailboaters are starting to over power your boats in calm and storms to the point that the boat now is being forced below the surface. Race ONLY in calmer conditions OR, get a hell of a lot better in the diving characteristics of submarines. If you try to have one hull do both conditions, IT will look like a complete freak of a boat. The cost of equipment destroyed and lives murdered in the uncontrolled need for more speed is really that of a very sick mind. You are about at the PRACTICAL limits of SAFE sailboating. Hard to admit ,but you are there. Rewrite the classes in danger to values that provide 1/2 the speed and danger. Racecars have done it to stop the murdering of the car drivers. It is now time for sailboating to do the same.

[Doug Lord]

I think there is a lot more potential for improvement in speed ,handling and seaworthiness by learning more about "foils and other appendages" and their applications. And far from operating under the surface the tendency appears to me to be moving above the surface to one degree or another.
No where near the practical limits of safe sailboating!

[cyclops]

Pitchpoling at 5mph is painfull. At +25 mph, its deadly due to the stonewall effect of water at that speed slaming a human body into wire stays, masts and all the other nonflexing parts of a racer. It is a instantanous slaming into all of the boats structure. It becomes a meat grinder for the crew. Has any builder designed that condition out of the race boats. Some examples are needed. All hands on deck is crap at 50 mph. There is no hint of giveing a crap about the human beings safety at speed. Against the solid water coming at him. I have seen what is left of bodies that are pushed along the decks of WWII destroyers at 53 mph and leaning so far over with full rudder that salt water was found in the smokestacks. The bodies had arms and legs ripped off by impact on anything that did not give. +50 in a sailer or a destroyer causes the same injuries.

[gonzo]

I am referring to foils and appendages added on to correct problems instead of those that are part of a design.

[John Perry]

As Andy P has said above, if a bow wing fails to prevent a pitchpole in the early stages it could easily start to develop downforce and actually make the situation worse. One way to overcome this problem might be to have a bow wing which is self pitching. I can envisage a tube through the bows a little above the waterline, with needle bearings in each end of the tube supporting an inner rotating tube to which wings are attached. The wings would have a vee shape looking fore and aft, i.e. the tips would be higher than the roots. They might even be 'gull wing' shaped, that is with steeper vee angle near the root than the tip. With this kind of geometry I think it should be possible to get the wings to stay at a constant angle of attack to the local water flow in much the same way that the blades of an 'Autoprop' propeller pitch automatically. This way the bow wings could maintain a constant upward force as the bows go deep under the water and this should surely do quite a lot to stop a pitchpole. Probably most beneficial for a fast multihull.

John

[Jocko]

Two quick observations about air/hydrofoils:
1.) Open wheel racing revolutionized by wings and downforce
2.) Fish

A billion Tuna can't be wrong. So what's wrong with foils on a sailboat? Besides, I find my own appendages worthwhile.

[Andrew Evans]

Re: adding to pitch-pole problem, if you refer back to the original photo of Bruce Schwab's boat, at http://www.bruceschwab.com/updt_usa05_2004/news_071904.html
you see that the underside of the wing is at a sharp angle to the hull, but the top side of the wing is at a very low angle to the bow. I believe this would mean the wing would be very effective at hitting the water below it, but would have little effect if hitting water above it.

Andy Evans
Foolish Muse.

[Haji]

Everyone is right to some degree.

OP should have had more bow flare (a la Moore 24...sorta) and a bit more freeboard up front. I actually pushed for more and this is one argument I wish I had won. The boat did not "pitchpole", it was a matter of too much water on the foreward foredeck really slowing the boat down when zooming into wave troughs. To change the hull and/or freeboard was not an economical option, so we looked at everything from the "Grundig" wing to adding foam/flare. The wings we figured would break/be too much drag/and possibly make things worse as mentioned above. Adding flare with foam would be too much material and heavy.

In the end, the combo of dynamic lift, low drag, and low weight from our version of a "bowlip" seemed worth a try. I'm happy to say that it really does work. Sure, water/spray stills goes on the boat, that is unavoidable, but the heavy green water on the nose is pretty much prevented and the boat no longer "stumbles" when nailing the back of a wave. Also, when working on the nose to hook up a genniker or spin tack I don't slammed like I did before.

So, yes it is help and we are leaving it on there, but the question for Andy is it really rough enough on the way to Hawaii to require it. In my experience it could be in a windy year or in big squalls, but on the average, not really.

Haji

[yokebutt]

Hey Bruce, you a permanent easterner nowadays?

Yoke.

[cyclops]

Are we talking about a wave 1' higher than the bow or a REAL 10 to 15' one. That scrawney little fin should do nothing when a wave 5' higher rolls over it. Look at the area of Penguin or Tuna flippers to body size. I think we are day dreaming on this topic. Race cars NEVER drop their front to a negitive angle, ever.

[John Perry]

Are we talking about a wave 1' higher than the bow or a REAL 10 to 15' one. That scrawney little fin should do nothing when a wave 5' higher rolls over it. Look at the area of Penguin or Tuna flippers to body size. I think we are day dreaming on this topic. Race cars NEVER drop their front to a negitive angle, ever.


Well, it should do something. What are we talking about - say 4 square foot wing area (say 0.4m2), 20 knots (say 10m/s) Cl = 0.5 (rather uncertain since it may well ventilate) then that is about a ton of lift. OK, it may well be quite a lot less than the bouyancy lift due to the bows being deeply immersed or submerged. Probably most worthwhile for a boat with narrow bows, eg a typical multihull.

John

[CT 249]

the wings on AAPT/Grundig are there to prevent lazy spinnaker sheets from getting sucked under the boat during gybes.

Not according to Sean, and he should know. He says they were there for lift but IRC wanted to look at the rating with them.

[Doug Lord]

Mr. Langman also said they worked very well downwind but because they were not retractable they weren't so hot upwind.

[messabout]

One time I had a Hobie twelve, yes twelve, foisted off on me. It would go pretty well but had a nasty tendency to bury the lee bow in a breeze. The little boat was too much fun to abandon. On the other hand I had no desire to be pitchpoled which was a sure thing if pressed on a breezy reach.

I had an old daggerboard that was nicely shaped. With a little surgery it fit between the bows. It was installed, horizontally of course, a few inches above the water surface and given a healthy incidence angle. Problem solved. When the lee bow went down, the board, now a wing, would lift enough to offset the problem. Spray a plenty, but it worked quite well.

All that said, I fear you might get into some structural problems on a monohull of the size you mention. A failure of one side of the wing could make a serious problem. Too serious to fool with.