Hi,

Does anyone know where I can find the practical top speed for my boat? It's a Hobie 18.

Thanks.

On the water, that thing will go about wind speed on a reach, close hauled somewhat slower. On the trailer its easy to measure- the speed of the car = the speed of the boat!, Ha, HA, I'm so funny

I'm glad to hear about the trailer. That's with the jib out or furled?

But seriously... There must be a practical limit, caused by, for example, the ability of the available weight of the helmsman and crew to keep the windward hull down. Or perhaps there is a maximum hull speed that is reached before that point?

I know there is a formula for estimating the max speed of a keel boat. (I think it's max speed in knots = 1.34 X square root of the boat length in feet.) But the formula doesn't apply to catamarans.

Well with rocket propulsion... I am guessing well over 200mph.

super-ludicrous speed!

They've gone Plaid!

Do a search, a while back there was quite a bit of discussion on this topic. I think you'll find that top speed is around 26 mph.

Mike

Thanks Mike.

I searched, as you recommended, and found some references. The only real practically arrived at number was 24.6 mph (which is 21.4 knots), posted back in 12/02. This fellow measured using a GPS. I'm going to take this as a "minimum maximum speed", for now.

I'm a brand new sailor. Knowing the limits of the craft gives me something to assess my own progress against. Not that I intend to set any speed records, but it just puts my own performance in perspective.

I bought a SpeedMaster trailing impellor knotmeter. It seems to work well. I clocked 12.8 knots Monday in moderate winds. Even that modest speed was lots of fun for me. I can't wait to get out in some stronger winds. (I'll probably dump us, but I'm sure it'll be great while were flying.)

Hey Kirkl
Where did you find that knotmeter? Sound like a fun gadget.
}=)))*>

It's a "SpeedMate" (sorry, not SpeedMaster as I previously wrote) Knotmeter from Speedtech. It displays current speed, max or average speed and distance travelled. It comes in a couple of models: one where the impeller has to be stuck to your hull; and another with a trailing impeller -- basically a wire with the impeller at the end that you drag behind you. In both cases there are no holes to drill . I bought the trailing impeller, since you never know if the hull you attached the gizmo to might be out of the water. It works great, so far. (I've only had it a week.)

I bought the thing online directly from Speedtech at www.speedtech.com. They're having a small sale on it right now for $160 U.S. (down from $180).

It keeps the maximum speed even when off, until you reset it. That way your friends can't falsely claim to have beaten your record!

Hey! When I posted this I expected to see all kinds of people bragging about how fast they've pushed their Hobie 18. When I got a question about my knotmeter, I started thinking... Maybe very few people actually know how fast they go. Is that so? Am I the only anal-retentive to search out and install a knotmeter on a Hobie 18?

probably.

Installing a knot meter or using a GPS eliminates your ability to broadly exaggerate during campfire stories!

GAWD! AND WE CAME DOWN THIS WAVE DOIN' LIKE 30 KNOTS MAN!!!!

by gps was 25.7 mph, under spinnaker.

Your friends won't trust it anyway - you can cheat with a blower, a drill, etc. to rotate the impeller faster then the boat sails

You will find knowing the max speed will not be a good judge of your sailing ability. Speed is depedant on the conditions. You will find that there are a lot of times where you will not be anywhere near the theoretical hull speed but the conditions make you feel your at twice that speed. By always sailing with just a little more power than you should you will quickly learn where the limits are.

Keep the pointy end up

Matt

Sounds right to me. I was interested in max speed more as an indicator of fun level and fearlessness than ability, really, anyway.

Do you think that speed is a good indicator, for a particular wind and tack, of how well trimmed you are?

The trick is to keep moving at a high average speed. Have fun practicing
Mike