With apologies to Mary, who raised this question a while ago :

"I hate to revisit this topic after the last thread where I got a little upset about people saying that small catamarans (20-foot max) cannot go faster than 22 knots. Now I have to say that this claim about 33 knots also seems totally unrealistic at the high end. The following is quoted from a story on the US Sailing website:

"The Tornado sailboat has the ability to reach speeds of 15-18 knots upwind and downwind, and 33+ knots reaching!"


Having read the ensuing replies, I could only find one or two posts that stayed on topic, as usual it was hijacked and went off in a direction of technical gadgets and how to keep Ni-cad batteries working etc, but not much on the subject of speed, and how fast a catamaran can/should/would/could go. In defense of the hijackers, Mary did ask how we could get an accurate measuring method, so all the techno-device junkies came forward.

Here I will probably get some disbelieving folks, but here`s my take on things from one case.

“1 nautical mile = 1.85200 kilometers”
"A knot is a nautical measure of speed, one nautical mile per hour"


Almost every country has a “Round The Island Race”
South Africa`s version is not as exciting as the UK`s, it happens on an inland dam and isn`t really a long-distance race, unless the wind is very light. Then “distance” can become a different perception, how far you drift in one hour rather than a physical measure. The race does, however, attract between 400 and 700 boats, and has become a cult following.

From the organising club`s web-site :
“The record was set by Eric Cook and his daughter Julie in 1998, with a time of 1 hour, 1 minute and 27 seconds (24 nautical miles). Every boat finishing before the cut-off time of 17h00 receives a certificate, and we have approximately 30 trophies to be won. A special prize of R10 000 is up for grabs by the first boat to break the one-hour elapsed time mark.”

This record was set on an old-rig Tornado, before the new rig was introduced (in SA at least.), without a spinnaker.

That gives an average speed of 23,43 knots, over a one-hour period, including an upwind leg of approx. 4km, which works out to a distance of 5,65km upwind, or 3,05nm, when considering they had to tack several times, so assuming they sailed the distance to the island and then the distance back in a dead straight line, they would have covered closer to 25nm in the hour.

So, to open up the debate on “how fast can catamarans sail over a 500m course”, I`d have to disagree with some that the fastest a Tornado can sail is 23knots, since this speed seems to have been sustained over a considerable period of time. What`s more is that this is the official race time, I remember a few years ago that some Tornado and Hobie Tiger sailors broke the hour by several minutes, claiming an unofficial time of 49minutes, but on the Saturday before the race. This is a big claim, since it puts the average time close to 30knots.

So, unless the organising club has the distance all wrong, or their timing was horribly out, I`d have to believe that Eric & Julie sustained over 23 knots for an hour. Since they had to tack, gybe and fight their way through some 400 other boats (the catamarans start last), they must have reached speeds well in excess of their average to sustain that.
The rough distance from the North end of the island on the Vaal dam to the start line is 22km, measured on the road parallel to the shoreline. Double that for the return trip and add 4km for the upwind leg behind the island gives you 48km, or 25,91nm, so I`ll believe they`ve got the distance right.
So in my book a Tornado with old rig can sustain over 23-25 knots for long periods of time without the spinnaker, and must have reached speeds in the upper 20`s (ie 27+) at times. (Spinnakers would have been no use in this race, it was a beam reach to the island, a beat up the back of it, and a close reach back to the finish.)

I`m sure there are many other cases where cat-sailors sailed a known distance between two points in a given time, so their average speed over that distance can be calculated ? Then we don`t have to get into lengthy conversations of how GPS do/don`t work, their accuracy, battery life, etc ! What about historical data from legs of the Worrell / Tybee 500 / Atlantic 500 races, which are sailed on damn fast boats ?

Steve

Why don't some regattas just have a 1nm drag strip marked out and time the boats as they run this? I suppose a shorter course could easily be used but I rather like the idea of an entire nautical mile, as it will better reflect how people sail in racing conditions when they are just as concerned with staying upright as going fast.

I believe the record for one leg of the Chesapeake-100, which would be approximately 50 miles, is something like 2 hours 15 minutes. But that was probably one of the dream scenarios of a spinnaker run up the Bay in a 20 knot SouthEasterly. Somebody from CRAC can tell the exact record?

One big problem you hit in over 20 knots of wind is the sea state. That will keep you from reaching the full speed potential as you run down into the troughs and climb the backs of waves. In France they have a long ditch filled with water where they do the speed records. No matter what the wind, the water is pretty flat there. I think a windsurfer came close to 40 knts. and the all out sailing speed record is close to 50...but you can't go that fast on a lumpy ocean. I don't know if they have ever run a cat down the ditch but it would be interesting to find out.

I once asked about the theoretical top speed of a Monster Cat like Play Station, the answer I got was about 60 knots, in flat water, but you can't find that much flat water and 30+ knots of wind to do it. They will do close to 40 in the open ocean.

In the right conditions (flat water, lots of wind) I'm sure you could get a Tornado with spin up to 30 knots or more.

2584 nautical miles in 326 hours = 7.9 knots.
20 foot beach cat crosses the Atlantic in less than 14 days; breaks record

(What a great boat!)

GARY

http://www.cat44.com/2004-miami-key-largo-yacht-race-miami-key-largo.htm

I have personally finished the race in 2:11 on my now deceased H-20. Iy was good enough for 10th overall. The Tornados finished well before me. I am looking for some past results to verify times.

"One big problem you hit in over 20 knots of wind is the sea state."
Hi Timbo, agree with you there. The race I used as a case study was on an inland dam, although quite large in area, the day of the race was quite unique, presenting ideal conditions to set that record. First leg to the island was a beam reach, but the wind only started blowing a short while before the race start, so the water was quite flat for the first leg. We (the cats) actually sailed a high course parallel to the shoreline, so were in very flat water since it was blowing "offshore", and then sailed a short deep reach across a bit of open water to the south end of the island. The beat up the back of the island was quite lumpy for us, but perhaps Eric had flatter water since he got there earlier than we did. (I had to do a woman-overboard retrieve, you just can`t get good crew these days ). 400+ keelboats that start half an hour before you can churn up a narrow passage quite a lot, and they are interesting to dodge going upwind - we saw a Dart 18 get run right over by a 30ft bus just ahead of us.
From the North end of the island we headed for the shoreline again since there seemed to be more wind there, and smoooooth water, and had a 20+km twin-wire close reach straight to the finish line. It just doesn`t get better !

So all said we probably had the best conditions for a record, which explains why it still stands.

Our time was 1hr34min, so average speed was 15,32knots on the Mosquito, a 16ft "baby Tornado". That boat weighed about 43kg more than my current one, so I`m sure we`d have one faster, just as I`m sure Eric would have too if they had the new rig & twin-wires.

Steve

"I have personally finished the race in 2:11 on my now deceased H-20. Iy was good enough for 10th overall. The Tornados finished well before me. I am looking for some past results to verify times. "

Hi Eric, now all we need to know is the distance, in nautical miles, and we`ll know what your average speed was.
Not too difficult. Anyone know the distance of that race ?

I believe that it is 47 miles as the crow flies, which puts us near 22.3 mph.

"I believe that it is 47 miles as the crow flies, which puts us near 22.3 mph. "
That`s 35,9km/h, or 19,73knots. If that`s a downwind race I`ll assume you were gybing angles. not sailing "as the crow flies" ? Makes a sustained speed of 20+ knots believable, eh ?

Passin' stinkpotters all the way, yes, down wind angles, 1 jibe. It was a hoot, trapped off the stern and hanging on to the drivers PFD to keep from tumbling forward when the bow stuffed.

>"One big problem you hit in over 20 knots of wind is the sea state."<

I agree but I am not so sure smoooooth water is ALWAYS the way to top sustained speed.
Perhaps some percentage out of the water it could be faster as hyperlink below.

http://www.catsailor.com/forums/sho...amp;Main=14693&Search=true#Post14761

http://www.windjet.co.uk/index.php?option=content&task=view&id=21&Itemid=56.

To quote my wife when she took the driver's seat while teaching her to fly my boat, "Shut up and hang on."

--Dean

Dean,

Isn't that site a little out of Date? Finnian broke the speed record at something like 48 or 49 knots at the end of last year.

Yeah, he did. I think he gained a few more pounds/stone and it was enough to break the record. So, the fastest boat out there...is a board.

Yellow Pages Endeavour's speed record of 46.52 knots was broken by Finian Maynard, sailing a windsurfer in the French Trench (as it's affectionately known) with a 500-meter run at 46.82 knots in November of 2004. The wind was blowing a solid 45-50, with a brief lull in the high 30's roughly as Finian sailed between meters 300 and 400. See Masters of Speed for the scoop, and info on the ongoing assault on the 50-knot "barrier".

27.4 nautical miles in the ocean under spinnaker. 2:11 hours. 13 knots. Two 200# men with approx. 100# cargo.
Blue highlighted section in attached photo.

Thanks Gary, you might`ave gone quicker if you lost the 100lbs of cargo and one of the 200lb men !

While the original topic is getting lost, I`ll add a deviation for the windsurfing supporters : Downwind Dash, Langebaan to Saldanha, Cape Town. Distance = 17km, record = 19minutes by Peter Slate. Average speed 53,6km/h, or 28,98 knots !!
Dean : Fascinating stuff, all those fantastic craft designed for the record, all claim to do double windspeed (but break up in more than 20knots). Thanks for the link.

Back to topic : Anyone else got some reasonably accurate data on average speed over a known distance ? (Gary, those guys who crossed the Atlantic must have been going real slow to average 7,9 knots, I managed that over a 4 day river trip on a Dart 18 with no spinnaker and 50kg of kit + crew, and we spent quite a bit of time just gliding gently in 3-5knot winds.) Then again it must be tough to always be in good breeze (and good mood)for 13 days. I would have eaten my crew by then.

Steve

What about some of you Worrell guys? There must have been many spinnaker runs with higher average speeds....

In my files I have all the times for all the legs of all the Worrell 1000's from 1998 through 2002, each year in its own looseleaf binder. Problem is, I don't have time to go through them. If someone wants to come to my house and go through them, you are welcome.