Foiler vulnerability to trash in the water

[Willallison]

Chris, stop picking on Doug.

As to the garbage- evidently it's a problem, certainly more so in some areas than in others. Getting rope and nets caught in props and rudders is nothing new to boats of any type, and getting a plastic bag wrapped around the lower unit is certainly no fun for the outboard engine that finds its cooling water suddenly cut off. I can see how Moth foilers- being light, fast and finicky- might be more sensitive to this sort of thing than some other boats. The manta rays- well, hitting anything half your vessel's size at twenty knots is going to hurt, no matter what you're piloting- freighter, car, train....

Now, how to teach the world's landlubbers the difference between a trash can and a beach......

Yeah... what Matt said.

 

[messabout]

AK I hit an alligator once while paddling my kayak on the Hillsboro river. Took half a box of detergent to get my underwear clean. Gators have a habit of lying just under the surface with only their nostrils and eyes above the surface. The distance between those two parts of the anatomy gives the observer a clue about the size of the beast.

And about Dubai; where were the Greenpeace folks when we needed them? They could have cleaned up the place pre race. Comedy aside, junk in the water has and is becoming an increasingly serious problem. It seems that we are living on the same planet with a whole lot of irresponsible people who dont give a damn about earth stewardship or even common decency.

It is not entirely uncommon to hit a half submerged steel container. It seems that quite a lot of them fall off their ships in mid ocean. Ships that lose them apparently make no effort at retrieval.

 

[ancient kayaker]

Gotcha message Messabout: if I'm paddling and I see a log that is looking back at me I'll:

1) aim at the eyes
2) aim at the tail
3) leap out and wack it with the kayak
4) toss a stick of dynamite in the water
5) throw my underwear at it

(multiple-choice question)

 

[marshmat]

4. Incidentally, it reminds me of a proposal a while back to propel a spacecraft by giving it a friggin' massive armour plate on the tail, and dropping a surplus nuclear weapon out the back whenever it needed some delta-V.

I'm really not sure what can be done about large debris. Ropes and bags are trouble enough to us outboard-engine owners, let alone anything with hydrofoils. Short of the Dashew Offshore approach (half-inch aluminum armour plate all over the hull bottom) I'm at a loss for ideas on dealing with this junk in smaller, lighter craft.

 

[peterraymond]

I'm at a loss for ideas on dealing with this junk in smaller, lighter craft.

Just sail on the internet.

 

[Cheesy]

More BS from Mr. Guest. Surprise me, too. If there's lots of junk in the water and that junk gets wrapped on the lifting surface, it shuts down the foil from lifting a Moth cleanly and at optimal efficiency... end of high ride until cleared. Affects things dramatically.

If you get junk on any other boat, it only slows it. Well, unless it's a veritable floating condo of a weed patch. Simple to fix for most boats that have moving boards, or weed cutters. Affects things minimally.

Junk, in this case, is the example mentioned: plastic bags

So, Mr. Guest... which would you rather have a foiler that doesn't foil, or a cat that just slows until you lift the daggerboard? For a World Championship Foiling Moth event, it can be catastrophic. Just ask Rohan Veal.

It sounds like you haven’t done a whole lot of racing on any relatively high performance boat that has dagger boards/keel etc. Anything on the keel will absolutely kill performance, speed will drop and you cant point. Possibly not as obvious as a Moth not being able to foil, but equally bad in a race situation. Maybe Doug does dream a lot but I don’t see why that means he has to come up with a way of preventing this.

 

[ancient kayaker]

... I don’t see why that means he has to come up with a way of preventing this.

- be nice if he/we could though. Why wouldn't weed cutters work for a foiler? Or is there an unacceptable performance impact?

 

[Cheesy]

- be nice if he/we could though. Why wouldn't weed cutters work for a foiler? Or is there an unacceptable performance impact?

Without having any first hand experience I would say you are correct as to the unacceptable performance impact, the same would be true for a lot of the sport boats around the place as well.

In terms of loss of performance on one of the sport boats I have sailed on there is a net gain (well less of a loss) in stopping and sailing backwards at the top mark (or anywhere else without the kite up for that matter) as opposed to pressing on with even a small bit of weed on the keel.

 

[Doug Lord]

- be nice if he/we could though. Why wouldn't weed cutters work for a foiler? Or is there an unacceptable performance impact?

==================
Terry, the leading edge of a foil is critical to its performance-making it sharp enough to cut weeds would negatively impact performance.
A solution that is being looked at more is having swept foils that would help on the hydrofoils but not on the vertical fin. The vertical fin on many bi-foilers is sailed upwind unloaded(with veal heal) and a sharp edge there might work ok.

 

[Luckless]

It is not entirely uncommon to hit a half submerged steel container. It seems that quite a lot of them fall off their ships in mid ocean. Ships that lose them apparently make no effort at retrieval.

I was under the impression that containers are only lost in storm weather, where recover operations would be deadly for the crew. (If you're in waves/wind that were powerful enough to wash strapped down steel containers overboard, do you really think walking around on deck is a great idea?)

 

[ancient kayaker]

I suspect containers are not much of a problem to small foilers that do not venture far offshore, except perhaps for big boats whose sponsors have the money to build another one!

The small boat cannot do much about big trash like picnic tables, and I suspect places with natural obstacles such as gators are probably less than ideal for boating in general and foiling in particular.

Weeds mostly grow upwards so will tangle with the foils first, no doubt that is why I see many swept-back foils in the pics you guys provide. There are no foilers in my area as far as I know; I may try to do something about that later!

Stuff like plastic bags and rope or nets of synthetic material can travel anywhere once in the water. This is an educational problem really. Such stuff floats out to sea once in the water: the key is to stop it getting into the water in the first place, or at least capture it before it gets into to large bodies of water.

Well, let's look at solutions the boater can employ ...

Chris is correct about the vulnerability of tee-shaped objects to picking up such trash, and the ability of a daggerboard to "hop" over the trash with a little help from the skipper or mate. Doug, I think a sharp leading edge on the vertical fin would soon become illegal after the first encounter with a swimmer!

I can visualise a pivoting fin forward of the foil that could retract when drag was encountered, hopefully taking the trash with it, but I have doubts about its effectiveness and it would likely create too much drag and also limit manouverability.

A swept-back strut would deflect a wrap-around object downwards onto the foil, and cause ventilation; doesn't sound like a good idea.

A swept-forward strut encountering a small object at the surface would lift it every time a wave passed, to where it could be snagged by a notch or hook. That could keep it out of the water most of the time. Simple, safe and just might work on bags and other small stuff.

Any more ideas out there?

 

[Doug Lord]

Doug, I think a sharp leading edge on the vertical fin would soon become illegal after the first encounter with a swimmer!

==================
Terry, I don't think the problem is serious in any respect whatsoever on dinghy foilers. That being said, the Melges 24 uses a retractable blade in the leading edge of the keel. It would work on both vertical and
horizontal foils if the expense was deemed to be worth it as opposed to reaching down with a "tool" if necessary to clean crap off the foil.
Hitting people with foils(vertical or horizontal) while underway would be bad anyway you look at.

 

[Chris Ostlind]

It sounds like you haven’t done a whole lot of racing on any relatively high performance boat that has dagger boards/keel etc. Anything on the keel will absolutely kill performance, speed will drop and you cant point. Possibly not as obvious as a Moth not being able to foil, but equally bad in a race situation. Maybe Doug does dream a lot but I don’t see why that means he has to come up with a way of preventing this.

Cheese, My-man...

I'm not going to list my CV for fast boats. It isn't necessary. Looks to me like you have pretty much agreed with my principal position with your comment, "Possibly not as obvious as a Moth not being able to foil, but equally bad in a race situation..."

Equally bad would mean that the time penalty for removal of the debris would be equal. A Moth that gets crap on the foils and it does not come off by operator machinations while underway, shows that the rider has to lay the boat over, get off and clean the foils, then get back on and get underway. After all….What is a foiling Moth if it's not foiling?

On a racing cat, by comparison, the skipper, or crew if two-up, would simply go to the effected board, raise it until the hull bottom clears the junk, drop the board and away you go. There's no laying the boat over action, just a quick up and then down again and it's done.

Now, I don't have a stopwatch setting for the difference, but there's a heap of reality that says that the cat board clearing is a whole lot faster than dropping a Moth and getting off the boat would be. That, to me, is not equal. It's a very clear disadvantage for a Moth that relies on clear foils for its performance.

You guys don't have to agree with me to make the argument substantive. You may want to indicate that overall, the business with weeds and plastic bags on lifting foils is insignificant. Maybe it is for the areas in which you sail. The rub seems to come when we have seen two World Championship Moth events have plastic bag incidents that left enough of an impression that it was seriously being discussed by those present, as well as the competitors who experienced the specific situations.

The title of the thread is "Foiler Vulnerability to Trash in the Water". It's real simple... they are, indeed, vulnerable. Looking to make other foils equally vulnerable, is not going to remove the facts about lifting foils. The design of the Moth foiler is very committed in a specific direction for performance. What has come along with the performance, is an increased vulnerability to debris that disrupts the lifting surfaces. The old design/engineering adage of, "there's no free lunch", is stringently at work here.

 

[ancient kayaker]

Chris: personalities and semantics aside, I think we all agree with your claim. The vulnerability has been established. However, I don't think anyone seriously believes "Foiler Vulnerability to Trash" is going to lead to the disappearance of foiling as a hobby or sport. Reading back through the posts I could not find one that claimed otherwise or that one design is less vulnerable than another. BTW I would prefer to deal with a clogged daggerboard on a mono than on a cat, given that the affected daggerboard would most likely be on the lee hull.

Now what do we do about it? Trash in the water is bad for the entire boating community, and indeed, for everyone.

Maybe the Summer Olympics should have the boating events located in the worst possible place for waterborn garbage as a means to highlight the problem on a World-wide scale. Every four years, we could have an international competition for the questionable honor of hosting these events! The winning nation would then have to cleanup its act. This could lead to the Olympics doing something useful for once.

 

[bistros]

Chris: personalities and semantics aside, I think we all agree with your claim. The vulnerability has been established. However, I don't think anyone seriously believes "Foiler Vulnerability to Trash" is going to lead to the disappearance of foiling as a hobby or sport. Reading back through the posts I could not find one that claimed otherwise or that one design is less vulnerable than another. BTW I would prefer to deal with a clogged daggerboard on a mono than on a cat, given that the affected daggerboard would most likely be on the lee hull.

Now what do we do about it? Trash in the water is bad for the entire boating community, and indeed, for everyone.

Maybe the Summer Olympics should have the boating events located in the worst possible place for waterborn garbage as a means to highlight the problem on a World-wide scale. Every four years, we could have an international competition for the questionable honor of hosting these events! The winning nation would then have to cleanup its act. This could lead to the Olympics doing something useful for once.

The Olympics just were located in such a miserable place. The host nation swept the overbearing algae growth under the rug as best as they could for the period of the Olympics and then proceeded with business as usual once the cameras were gone.

Competitors were (sanely) very afraid of capsizing in China as they would have had to swim in one very large, unregulated sewage basin, complete with thick green frosting of algae.

Crap on hydrofoils is just the same as crap on skiff foils - you dump the boat, swim around and clear the foils and re-start sailing. We've got a weed problem here, and since Canada is pretty carefully regulated environmentally, there is no legal and effective chemical weed control option.

I wish the City of Ottawa was as careful with storm sewage overflow as they are with weeds - they've dumped millions of gallons of raw storm sewage into the river here by "accident" (meaning they accidentally left fixing the problem out of the budget for decades). Unsurprisingly, the sailing clubs are almost all upstream of the storm sewer problems.

Foiling is a small boat activity in the most part with intentional capsize and manual clearing an acceptable solution. This is just one more reason why larger scale foilers will remain the exception rather than the rule. Same goes for launch / retrieval. Walking a boat out into deep enough water works fine, and the complications and potential for calibration trouble with retractable T-foils renders the solution worse than the problem.

I know the voice of simplicity and practicality will now be attacked for the heinous crime of common sense.

--
Bill