I am almost finished with my TheMightyHobie18 project. I have a '82 18 magnum that is now converted to a SX w/spi. Running 18SE jib, Tiger main and Tiger spin w/snuffer. 18SE jib is larger than SX, Tiger main is of comparable size to SX and spin is smaller than SX. US Sailing portsmouth lists a DPN of 71.3 for Hobie SX-18 spi. I can't see why my boat wouldn't fall under that portsmouth number for racing. Am I right or wrong? Would there be an advantage for using a different number with penalties? The boat is all Hobie, just different parts from different boats. What do you guys think, I will most likely race it the second weekend in August.

What is the 18SE?

This sort of situation is really impossible to treat fairly under Portsmouth. You've changed the boat too much for any base class + modifications number to be realistic.

Based on what you said, I would start with the 18SX number (71.3) and take a JU (oversize jib = .995) and MN (non-class legal main = .995 ) for a D-PN of 70.6. I think that's a pretty generous number, considering that the stock TheMightyHobie18 has a D-PN of 71.4.

There's no modification factor for a undersize spinn, but if it's not at least as fast why would you use it instead of the class-legal one?

The scorer might also start with the Hobie 18 base number and hit you for a JU, MN and SP, for a D-PN of 67.9. I doubt the boat would sail to that number.

Take off the wings and put on a smaller jib, and it sounds like you have a Formula 18.

Are the wings what make the huge difference in Portsmouth rating?

Formula 18 rating is 62.4

I always got the impression that the Hobie18SX was a bit of an underachiever and that's why it's rating is so soft. With some modern sails, I'm not sure how that thing should rate or how you could even begin to do it fairly.

Well, he has a Tiger main and a Tiger spinnaker and snuffer.

I would think the only differences between him and a Formula 18 are the wings, the larger jib, and, well, he probably has a comptip mast.

Anyway, I am just wondering whether anybody has tried to convert a stock Hobie 18 into a Formula 18. What is required to do that? A taller mast? And an untapered mast?

The Hobie 18 and Formula 18 are basically the same minimum weight with all equipment on board. There are LOTS of older Hobie 18's out there, so why can't we get them into the Formula 18 class? Is it because you-all don't think they would be competitive? Or what?

For whatever reason, the Formula 18 rules do not allow curved beams. So none of the Hobie 18's would fit within the rule without some pretty substantial modifications.

The hull shape under the water is really not that dissimilar from the tiger but the boards are obviously not as high aspect ratio.

Why would the Formula 18 Class not allowed curved beams -- unless to prevent the older Hobie classes from participating??

18SE is the term Hobie went to after the SX came into existance. Standard 18 with 28' mast. SX has a 29'6 stick and mylar/dacron radial cut sails. The Tiger spin is a more current assymetrical shape, faster than the SX chute. I am not a racer, just a guy that likes to race every once in a while. I just want to be sure I represent the boat correctly to the race committee. I don't understand the portsmouth number system, is a higher number better or worse? Formula 18 never took off so open class is the only option I think. I got a little carried away with this conversion. Wanted a spin, got one that is white, gray and black. Thought about how good it would look in front of a smoke main, got one. Didn't want to cut the sail down so needed a taller stick, got one ( SX ). So here I am. Been sailing with the 28' stick and spin for about 2 months now and love it!!!!! Just now repairing corrosion damage on the 29'6 stick and will have it done this weekend. Will need to cut down a 18 boom since the foot of the Tiger is smaller. I would be happy to race and not be placed at all in the end, don't want to effect others season results. Just curious about overall speed and racing is the only way to compare. I feel the boat will be substantially quicker but not sure.

Surely you mean the Hobie Fox...Formula 18 is very popular.

Mary, If I were to guess (and this is just a guess), it was to simply try and keep things simple and prevent as many loop-holes as possible. I can't imagine what kind of loophole comes into play from having a curved beam though...maybe less freeboard and windage in the hull? I do know that among other important measurements, some mast and spinnaker measurements are based from the main beam - but I'm not really sure.

Jake,
Under portsmouth they show a formula 18 class prior to the F18 class. So, 18, 18magnum, Formula 18 and 18SX. All the same platform. I even have the specs for formula 18 which is the class I was reffering to. It comes up under non-participating classes. As you know even Hobie USA gave up on the Fox. BTW, got a call the other day from the guy that has my Fox and he's really enjoying it. Hope he never sails it very hard, it will most likely break a dagger again.

Well, the mast height on the Formula 18 seems to be based upon height above the main beam. But that could be easily changed to compensate for curved beams or enormously FAT beams, etc., so the class could be more inclusive of existing clases that fit within its parameters.

In the Portsmouth "inactive" group they show a Hobie 18 Formula. That has nothing to do with any formula class of any kind. It apparently was just another version of a Hobie 18, like the Magnum and the SX.

Actually it was based on a standard 18 with specific upgrades ie: downhaul, mainsheet config. Believe the details are still available from the hobie web, don't have it with me. I don't remember anything about a spin in that spec.

You can't use a number if you aren't that boat.

It's not fair to the system nor to the other sailors. Just because you 'think' you ought to have a number doesn't make it correct use of the system.

Boats' base number are figured according to how they are configured as described, eg STOCK. Modifications are MODIFICATIONS, regardless of how they were achieved, and should be calculated as such. You aren't racing an SX, you're racing a modified TheMightyHobie18 Magnum.


You have to work with what your boat was TO BEGIN WITH, and you say it was an 80's model TheMightyHobie18.

What you have, and how I would figure you:

You started with an 18 magnum, so you start with that number:
Hobie 18 & 18 Magnum TheMightyHobie18 71.4 76.8 73.5 69.5 66.8


You have a larger than stock jib, so you get hit for that:
JU For larger than standard jib 0.995 0.984 0.990 0.995 1.000


You added an oversize main, so you get hit for that:
ML For non-class legal mainsail, of greater sail area* than standard main 0.980 0.969 0.975 0.980 0.985


You added a chute, so you get hit for that:
SP Class normally without spinnaker, genoa, reacher, hooter or wire/rope luff headsail attached to a pole, carrying one or more 0.960 0.953 0.958 0.960 0.960


So, let's figure your base number:
71.4 * 0.995 * 0.980 * 0.960 = 66.8

That is what your base number should be, 66.8... NOT 71.3... sorry if you don't like it but it would be more fair, and is how the system is meant to work.

If you are modifying to conform to the Formula class, and you measure as such, you might could take the F18 number, but that is only given that you fit under the Formula rules. Anything else is truly not fair.

Certainly, the authority to answer this question is the Portsmouth maven, Darline Hobock. She can be reached at dhobock @ aol.com

(but I bet she agrees with me...)

sea ya
tami

My 1990 Hobie 18 was dubbed a Hobie 18 Formula... the main difference was the wing design as compared to the magnum wings... the formula wings had a longer top section... about another foot on each end as compared to magnum. The boat also came with some upgraded main and jib blocks and I think black annodized as opposed to silver. Other than that, it was a standard TheMightyHobie18.

Boudicca,
I agree with you and thats why I'm asking the questions. My jib is an 18 jib, not oversized. The Tiger main has less sq. ft than a SX for sure and almost the same as a standard 18. So the only hit would be for the chute, right?

If your main is not class legal but less than 1.05 times the stock area you have to take an MN adjustment (0.995 * D-PN). If it is more than 1.05 times the stock area then you take an ML adjustment (0.98 * D-PN). A non-class legal sail is always assumed to be faster regardless of its size.

There is no official adjustment for non-class legal jib of same sail area or less.

A boat with a lower portsmouth number is faster, so you want a high number.

If your boat is class legal for Hobie 18SX other than the sails, then I think you can make a case that you should start out with the Hobie 18SX number. If it is not, then you do need to start out with the Hobie 18 number and take an additional hit for the spinn. This makes a big difference.

So it looks like if you start as a Hobie 18 you take an MN and SP adjustment. If you start as a Hobie 18SX you take an MN and JU adjustment. The latter will get you a higher number. You should double-check the sail area of the main though - "same sail area or less" is defined as less than 105% of the stock area.

WindyHill,

you cannot start calculations as a Hobie 18SX because your platform is not SX. It just ain't right, as they say.


Therefore, if your jib is the same as stock, then you'd take the hit for the main and the chute alone, yes.


But, if it is NOT a STOCK jib, then you should, to be fair, take the "other" adjustment:

Other
Any other deviations from standard class configurations, including the addition of wings, can be assessed a penalty of at least 0.995. Multiple deviations may incur multiple penalties. Penalties may be greater than 0.995. Please identify any such modifications and penalties assigned and include with results reported to the handicap committee and Portsmouth Numbers Committee



Like Rhino said, depending on the oversize or not of the main you would need to take the 0.995 (which is the squarehead adjustment, 5% larger OR LESS) or the 0.980 (which is the oversize main 5% larger OR MORE).


I maintain that it would not be right for you to start as a Hobie 18SX, since your platform, as you have stated, is 18 Magnum.


I'm having similar issues with my Fboat, which is heavily modified. I'm knocking myself for modifications which aren't even listed, and using the 'other' .995 calc. for them, based on what I'm getting hit for vis. PHRF number recommendations.

Just take the hits. People will whine no matter what, but at least you'll be in a position to say, 'well, I took the maximum knock' when you go kickin they butt ;-)

sea ya
tami

Did you notice that the TheMightyHobie18 SX (with spinnaker) rates a 71.3 and a regular 'ol Hobie 18 rates a 71.4. There's NO WAY you can start with an SX rating and be even remotely fair.