16-18' "Sit-in" Planing Monohull ("Trapwing")

[mark_m]

Doug,
I did base the model on a 12ft transit in one second. I think this was a mistake as the typical movement will probably be 9ft, even though as Bill points out, the maximum move is 18ft.
I've updated the model to reflect this and it does make it look more favourable. (it is now 20lbs of batteries required per hour of sailing). The spreadsheet should be set as shared so feel free to plug your own numbers in.

Originally Posted by mark_m

Doug,
I did base the model on a 12ft transit in one second. I think this was a mistake as the typical movement will probably be 9ft, even though as Bill points out, the maximum move is 18ft.
I've updated the model to reflect this and it does make it look more favourable. (it is now 20lbs of batteries required per hour of sailing). The spreadsheet should be set as shared so feel free to plug your own numbers in.

=======================
Mark, you might want to take this information into account. Here is how long it takes to tack several different boats(max rm to max rm):
1) Windmill-4 seconds
2) 505- 5 seconds(full out on trapeze to full out on trapeze)
3) FD- 7 seconds(full out on trapeze to full out on trapeze)
4) Aussie 18 7-8 seconds(full out on trapeze to full out on trapeze)
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The ballast movement on the trapwing should reflect something around 6 seconds,max rm to max rm( 3' per second speed).
If we can do 4' per second the tacking time would come down to 4.5 seconds. To calculate battery capacity I would figure one tack every 3 to 5 minutes for 4-8 hours. That doesn't mean you'll tack that often- but it is an estimate of the total use over a given period(educated guess). It may be revised as we learn more.
And, depending on a lot of factors, lithium batteries should be considered.

[Chris Ostlind]

So, I get this pair of emails this afternoon with Doug's exclamation mark pronouncements as follows:


"Thanks to Rick Willoughby for his invaluable help! 4.6 to 5.8ah battery required for approximately 8 hours-very light particularly using lithium cells which I work with frequently.
Here is the spreadsheet he came up with: "


So, Douglas... where's the spread sheet from Rick W in OZ? Please tell us you aren't simply playing bait and switch again like a used car salesman.

And about that business of slapping exclamation marks on everything in sight.

Let the passage below serve as a guide for future use.
http://www.informatics.sussex.ac.uk/...on/node06.html


The Exclamation Mark

The exclamation mark (!), known informally as a bang or a shriek, is used at the end of a sentence or a short phrase which expresses very strong feeling. Here are some examples:

What a lovely view you have here!
That's fantastic!
Johnny, don't touch that!
Help!
Good heavens!
Aaarrgh!

Examples like these are quite normal in those kinds of writing that try to represent ordinary speech ‹ for example, in novels. But exclamation marks are usually out of place in formal writing. Using them frequently will give your work a breathless, almost childish, quality.

An exclamation mark is also usual after an exclamation beginning with what or how:

What fools people can be!
How well Marshall bowled yesterday!

Note that such sentences are exclamations, and not statements. Compare them with statements: People can be such fools.
Marshall bowled very well yesterday.

You can also use an exclamation mark to show that a statement is very surprising: After months of careful work, the scientists finally opened the tomb. It was empty!

It is also permissible to use an exclamation mark to draw attention to an interruption: On the (rare!) occasion when you use a Latin abbreviation, be sure to punctuate it properly.

Otherwise, you should generally avoid using exclamation marks in your formal writing. Don't write things like this:

Do not use exclamation marks in formal writing!
In 1848, gold was discovered in California!

Don't use an exclamation mark unless you're certain it's necessary and never use two or three of them in a row: This is a sensational result!!!

Thanks to Rick Willoughby for doing this-very cool and gives results quite a bit different than the previously posted spreadsheet(which was based on way too high a speed). You will have to click on "options" to enable macros.The spreadsheet moves the weight the distance you set in 1.5 seconds(for one cycle).The spreadsheet also incorporates a 20% grade-uphill(which the ballast would see infrequently). Rick has been a very big help-incredibly generous with his expertise!
Moving 70kg(154lb) 5.49m:
--in 4.5 seconds requires a 7.1 AH battery for well over* 8 hours of ballast movement equivalent to 5.49m(18') every 5 minutes.(1.83m in 1.5 seconds)
--in 5.49 seconds requires a 5.8 AH battery for the same(1.5m in 1.5 seconds)
*and I do mean well over....
------------
Have had some trouble posting this but seems to be ok now.

[Chris Ostlind]

Originally Posted by Doug Lord

... and gives results quite a bit different than the previously posted spreadsheet.

With no intent to cast aspersions at either solution set, the obvious question that emerges is, Which one of them is correct?

Doug, I should think that a guy like yourself, who is so handy with numbers, should be able to dose that whole tamale in no time at all and make one of your, "It's a Revolution!" pronouncements. That will let us rejoice and we can all be on our way, safe in our homes this evening.

This is, indeed, a fundamental dilemma. Conflicting data points with Doug right smack dab in the middle.

I'm making a run to the concession stand. Popcorn and soft drinks anyone?

[Rick Willoughby]

Originally Posted by Chris Ostlind

With no intent to cast aspersions at either solution set, the obvious question that emerges is, Which one of them is correct?

..

Chris
They both could be. I did not check the other one for accuracy but it was a monster motor to move 70kg. I think about 4kW. You would need to be super human to develop that sort of power yet all that the mover does is shift the weight of a person around. Even an average person producing 100W would soon tire. I did not spend much time validating my calculation but it is about right given what I know about the power output of human beings.

There are some implicit assumptions in what I did for Doug. It assumes the weight accelerates smoothly up to peak speed and then decelerates. So it never moves at steady speed but either accelerating or braking. Also it is assumed to be regenerative. This is normally done in this sort of servo system where energy is at a premium.

The trick to conserve energy would be to avoid having the weight travelling up an incline all the time. So the aim would be to anticipate the roll and counter before it becomes too severe.

A lithium battery for this sort of job would not be very big. Would recommend A123 if it gets that far.

Rick W

The drag in the system can be set by adjusting the slope a little more than it might be in practice.,

[sigurd]

Nice. would you put an RC gyroscope in it?

The key difference between the two power estimates is that Ricks uses much slower and more realistic speed based on how long it actually will take to tack. The first spreadsheet used a speed of 12'(3.66m) in one second. In reality the speed will be between 1.5m per second and 1.82 m per second.

[CT 249]

Well, an International Canoe is pretty similar. In my club races, I was tacking or gybing about once a minute.... possibly more in class races at times.

In addition, you're regularly moving the ballast (the human body) from full extension to at least half-way in about once every 30 seconds at times. If you had a dead weight on the plank end (rather than a human body, which doesn't weigh too much when immersed) capsizing to windward would be a common experience.

I haven't timed my tacks, but I stood up and run down the plank like you run across the wings of an 18. Get it wrong and you're in a world of pain. You are doing all this by moving the legs, because one hand is working the mainsheet frantically and the other is on the tiller.

Do that for an hour, and then add the almost continual smaller movements. It's a lot of work.

BTW when i've timed Schiedt tacking a Laser on video, he's taken 4 seconds and I cannot see an 18 etc doing it as fast as Doug says. Of course, my 18 Footer experience is minimal.

[Chris Ostlind]

Guys, guys, guys

Since our friend, Douglas, worked so very hard to cancel-out the importance of this "design" when it comes to disabled folks... does anyone really believe that older people are going to have any kind of interest in a boat like this?

I shot and directed a documentary regarding geriatric studies some years back. During the shooting, it became very clear to me that human beings, as they get older, do not seek the same excitement and danger levels they may have experienced when much younger and in much better shape.

Early in his career as an educator, my own father, now passed away, was a science teacher during the school year and a lifeguard in the summer months. He was an accomplished Waterman and at one with the sea as much as any guy I have ever known. As he grew older, he began to back away from the tougher pursuits, the swimming in the surge around rocky shores, taking on the bigger, body surfing locations, etc. In his late 70's he often hesitated when it came to sailing with me when the wind was banging it pretty hard in SoCal.

Older people do not sense less vulnerability just becasue they are seated in a new whizz-bang techno scooter. Quite the opposite, in fact. They typically reduce their involvement in activities in which they will be put into a condition where they experience less control of basic things like balance. Yeah, sure, you can trot-out the guy who is jumping out of airplanes at 80, but he is far from the norm and, I suspect, he always will be.

If you really want to do a boat for the elderly, or those with everyday disablities, then something along the lines of a responsible lake, or harbor cruiser makes a whole lot more sense. Shoving excessively complex machines in the face of people who are typically looking to have their lives simplified is a fairly substantial wheel spinning exercise. IMHO

Until you can change human nature and the simple realities of the ageing process, this design will remain a mental jerking exercise. If Doug wants to build it for himself, which I doubt will ever happen, then he should head on and enjoy the exposure to the chemistry in his "freshening years". Until someone actually does a considered and thorough study of the purpose of such a craft and its value to the human experience, I'm removing myself from the discussion. I have way too many things to get done that are substantively connected to my own design work.

Originally Posted by CT 249

Well, an International Canoe is pretty similar. In my club races, I was tacking or gybing about once a minute.... possibly more in class races at times.

In addition, you're regularly moving the ballast (the human body) from full extension to at least half-way in about once every 30 seconds at times. If you had a dead weight on the plank end (rather than a human body, which doesn't weigh too much when immersed) capsizing to windward would be a common experience.

I haven't timed my tacks, but I stood up and run down the plank like you run across the wings of an 18. Get it wrong and you're in a world of pain. You are doing all this by moving the legs, because one hand is working the mainsheet frantically and the other is on the tiller.

Do that for an hour, and then add the almost continual smaller movements. It's a lot of work.

BTW when i've timed Schiedt tacking a Laser on video, he's taken 4 seconds and I cannot see an 18 etc doing it as fast as Doug says. Of course, my 18 Footer experience is minimal.

-------------------------
I watched the Ronstan 18 video to try to get an idea of how quickly they tack. 98% of the video is offwind so it wasn't easy. I watched several 505 videos to get that timing and two FD videos. I crewed on an FD a long time ago-two long to remember.
I think people would be well served to actually watch top level racing in all these classes -in a good wind. There is very little
in-out crew movement upwind-surprisingly little. I'll post the FD and 505 videos later.
The important thing is that moving the weight electrically is not only feasible it is probably the best way- whether the boat is sailed by an able bodied skipper or mobility challenged skipper.

Watch crew movement:
One of a few FD videos: http://www.youtube.com/watch?v=7bxRT...eature=related
505 video: http://www.youtube.com/watch?v=0yyPY...eature=related

Originally Posted by sigurd

Nice. would you put an RC gyroscope in it?

-----------
You could fairly easily.....

The trapwing concept is more alive than ever thanks in part to Rick and to the exhaustive model testing with on-deck movable ballast. It works well
and will provide an exciting, unique sailing experience that will be extraordinarily fast. There is nothing like it anywhere.
There are few experiences as cool as being able to control the movable ballast of a boat you are sailing-model or full size.
The concept represents a way to go very fast under sail with very little physical labor and, as such, represents a whole new way to sail!!

[Paul B]

Originally Posted by Doug Lord

The trapwing concept is more alive than ever..!!

How?

It is not something I see anyone wanting to build. In fact, I think it sounds like a ridiculously overcomplicated idea.

We know you'll never build it.


So how is it "more alive than ever"?

[CT 249]

Originally Posted by Doug Lord

-------------------------
I think people would be well served to actually watch top level racing in all these classes -in a good wind. There is very little
in-out crew movement upwind-surprisingly little. I'll post the FD and 505 videos later.
The important thing is that moving the weight electrically is not only feasible it is probably the best way- whether the boat is sailed by an able bodied skipper or mobility challenged skipper.

Watch crew movement:
One of a few FD videos: http://www.youtube.com/watch?v=7bxRT...eature=related
505 video: http://www.youtube.com/watch?v=0yyPY...eature=related

I think some people would be well served to go out and sail an 18 or Canoe. They would find that even with a world champ each side of you, getting an 18 off a typical beach or through a move requires intense and rapid body movement. Same with a 16, sailed by #3 in the Laser worlds and two other former Laser champs.

Those who have raced with or against world champs in FDs, 18s and ICs know that they DO require a lot of body movement at times. A few vids of the top guys sailing in steady air does not give the correct picture of the way the typical crew sails in normal conditions. Of course the crew are steady in a good steady wind. It's when the wind isn't steady that the workrate becomes very high.