How do you rate a one-off boat?

We will be racing DPN and since it is not a measurement based system, how do you give a beginning rating? Or do you sail some events as a non-competitor to generate data points?


It will be a real frankencat.

looks slow... needs more sail area... or an evinrude. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

I was thinkin a ketch/junk rig w/ lee boards...

I don't know the answer to your question... but i'd suggest investing in some cradles for your trailer for those HT hulls.

That trailer is a temp. The aluminum trailer will get a ply deck w/ carpet. Cheaper, easier and supports the hulls better than cradles.

I thought those looked like HT hulls. Definately use cradles or a well padded flat deck. The hulls are very "tender."

Up the frankenboat factor with some risers for the rear beam.. absolutely necessary IMO with that boat in any sort of chop downwind.

I'm not sure that a flatbed would support it better. You have to remember that there's rocker in that there hull, and strapping it down to a large planar surface might result in the hulls getting "flat spots" where it met the wood.

There's a reason why everyone uses those cradles, and its not because they are cheaper than plywood.

No worries on the trailer. We can trim in foam to fit the hulls.

BTW, I have a relatively easy and cheap way to make those risers if you want to know how.

Flip the hulls over, cover in plastic wrap or tinfoil and then some glass and resin. Piece of small al. pipe glassed in for mount point.


Anyone have an answer for my question?

I meant risers to get the rear beam further from the water. Have you noticed how much the rear beam slaps the water and slows you down when running downwind?
anyway...
take the dpn of the original boat and then use all the multipliers to get to a decent starting point. There are modifiers for oversized main, no jib, jib on a boat normally without, etc etc etc...
http://www.ussailing.org/portsmouth/tables06/modifications06.asp
tell us what you did to change the thing and we can then calculate a starting point at least.

LOL.

Transferring the dead G-cat rig to it. So the 59 is not going to be accurate.

Yeah, that is going to be complicated. Are you putting a jib on it too? not that you asked, but might be a problem with loading up the bows with a forestay low enough to get the jib on. Will pull the hulls in too much. May need a bow foil... but I digress.
The 59 isn't accurate for full on HTs either!
Get it out and do some speed trials against a known DPN boat and see how it plays out. In the end you will probably need to bargain with the race committee. I don't see it as a huge problem with maybe local club racing but it certainly would be if you had some high maintenance competitors around or if you were racing the boat in an Alter Cup qualifier etc. In the end though, people who have been more involved with RCs would be better to chime in (JW, JK, etc)

Just racing for fun. Yes, the jib is going on it so some type of foil or crossbar will be necessary.

leave the jib off and put on a spin. Ive got one for you, came off my F18. Its in fair shape, but its cheap! Get that boat to Tommy Whitside, we will rate it for you. And Bill Hendrix will be there with his one off TheMightyHobie18/20(were not sure how long it is) but its got a nice Tiger main on it, and he is one of the best sailors around. His Frankenboat rules! he is the aster at making a sq top out of an old sail.

Very cool, Dave. That plan was for jib AND spin or hooter. And yes, reinforcing key points. We have an old Stiletto main that could be used for sail mods.

PTP,

I'm currious, how do you put in the risers for the rear cross beam?

Construction, mounting, etc.

Ditto.

Glad to see you got that thing bolted together.

I cant help on the rating.

Yes, to the cradles not rollers.

Rear beam risers were traditionally made for the HT out of carbon, only a handful of boats added them, the boat will slap the chop downwind, but you'll need a very short steep chop and frankly the condition that causes the slap doesnt happen that often in my opinion. If its honking out, it will happen, but under 15knots probably not very often. I wouldnt worry about it for now. Chicken lines are an easy way to deal with the slap. The Risers I've seen were made by a guy in P'cola area, Bauwman I think was his name, I probably butchered that. Anyway, carbon bolted to aluminum isnt a good idea, its a nice way to get all kinds of electron swapping. I wouldnt do it.

If you are really set on risers, call Forte RTS, order a new carbon rear beam for $400, he's got the spec's, ask him nicely for a couple of cut-offs of the same diameter and glue them on, layer on carbon cloth to taste. I can post pictures of my beam at some later point.

Bill

I bought some 4 inch OD aluminum beam from onlinemetals (I believe it was 1/4 inch thickness... clearly overkill, could probably go with 1/8 thick). I cut three lengths that were, I think, 8 or so inches. I will need to post pics but I basically cut the "top" off the tube then cut a larger top off the extra tube, turned it upside down on top of the open tube and had it welded by a local dude. I used the extra length to cut a larger top so that the beam would have more to rest on. I made them so that they raised the beam almost a full 4 inches. I then cut a total of 6 2.5 (or similar) inch circles in each to lighten them (on the sides that sit on the beam and receive the beam so no one would get fingers/hands/feet caught in them. I also bedded the beam in epoxy (after coating with mold release). Total cost was about 150$. It ended up being slightly heavier than the carbon ones a friend has. It was a much better option than the 600$ than Bauman would have needed to make the carbon ones, and still better than the 400$ that Bill mentioned. They are bullet proof (probably literally) and make a world of difference if you sail with a somewhat heavy crew on the HT. If you are seriou, I can have a friend show some pics.

BTW, just checked here:
http://www.onlinemetals.com/merchant.cfm...&top_cat=60

15/ft. Can't beat that! figure 40 or so for welding, you are looking at less than 100$. hard part of the whole deal is cutting it, but it would be easier with the 1/8 than the 1/4 I used. It would work on any boat that has the problem of slapping. As bill said, may not be a problem, but on my old HT with a total crew weight of almost 400 lbs and not a lot of bouyancy in the bows, getting to the back of the boat to fly the spin meant a lot of dragging and going slow.

Hi PTP

Pictures would be great!
We have allot of Javelins in our 18HT class. So that would be interesting.

You need to come up with a logical way to derive a rating but none of this is an exact science and would be open to some debate - I'm assuming the rig comes from a Gcat 5.7?

G-cat 5.7 (without spin): 72.7
18HT (with spin - 2up): 59.6

Modifier for boat normally with spinnaker sailing without one: 1.020

18HT (woutOUT spin - 2up): 59.6*1.020 = 60.80

now is where we have to get creative; the 18HT w/o spin is at 60.8 and the Gcat at 72.1. In this scenario, I would estimate that the rig probably has about 80% to do with boat speed and the hull (w/ modern daggerboards) and boards have about 20% effect. So I would take the difference between the two ratings, and put the rating on the boat it 80% toward the G-cat rating over the 2-up spinless 18HT.

Gcat - 18HT(no spin) = 72.1 - 60.8 = 11.3
80% of the difference = 11.3 * 80% = 9.04
18HTGC = 60.8 + 9.04 = 69.84

69.84 is where I would start.

I think I would start with a maybe clearly "too fast" number than a "too slow" number. In the end it will still be a light boat. How much sail area will it have with the main and jib? will it be anywhere near the 20 sq meters that the original main only HT rig?
I like Jake's thinking though, but might start at 66 or something.

Obviously you are not talking about Texel-rating? The calculator for this can be downloaded here:
http://www.watersportverbond.nl/content.asp?me_id=468%20
(english explanation)

How about using the Texel calculator, find a simlarly rated boat in Texel rating system - that also has a US Sailing DPN and use that.

An example only (not a prediction): The Texel handicap calculator gives the same rating as a Nacra 5.5 SL, use the N5.5 rating from the US tables as a starting point....

Excellent help, guys!

I am OK racing just to build data. The G-Cat has 225sq/ft total sail area w/ jib- 20.9 sq/m. (but old sails- maybe newer ones next year.)

We could start with the estimation that Jake worked out. I will take a look at TEXEL and see if it will make sense.

And thanks, PTP for the spacer description. We could make that fairly easily. We will see how the boat sails first. We will be right at 400lbs crew weight. Mostly lakes and coastal rivers/harbors.

J.

Hmmm,

Using TEXEL rating and guessing on boat weight, no spin, 1 trap, hard numbers for jib size and extrapolated main I arrived at 106.

Same as an F16. DPN 65.2. I really doubt the boat could sail to that w/out spin. But, could be wrong.

Here are the rear beam mods. the first pic is the carbon mod and the second is the aluminum.

Here's the aluminum mods

Come to think of it, I didn't really factor in boat weight when I made that 80/20 assumption...I would put it closer to 70/30.

Check out www.schrs.com as well.

Thanks for the pictures!