DN NA Class

I was wondering if anybody has any recent statistics about iceboat top speeds or other interesting data on angles or boat speed/wind speed ratios etc.  I am doing some research for a  presentation about iceboating that I have been asked to give at a yacht club here in Toronto next week.  I have been sailing a DN for about three years and have done a little local racing but am not really in touch with recent developments.

I have seen two excellent articles by Bob Dill and a few other posts on this forum.  Are there any other interesting or more recent data that would be fun to talk about?  I have searched online but cannot find an officially recognized world speed record for iceboats.  Am I missing something?

Any input would be appreciated!

     

   

So there is a lot of BS about top speeds in a DN and other iceboats. Supposedly some of the stern steerers have gone 140 mph, in ancient days when speed was measured by timing them with an hourglass as they sailed between two mountain peaks.  But that of course is a crock of sheisse.   

Bob Dill is about the most athorative source out there.  He has the gear to measure speed carefully and has spent quite a bit of time researching it.   
Around me a lot of the cruisers carry gps’s and are a bit obsessed about max speeds.  I have looked at gps tracks from James Lamb sailing a  pocket skeeter (Wizz) going around 72.
DN’s seem to max out just a bit over 60 mph.  I know from sharing a race course with bubble boats, that they go a lot faster than a DN. 
In the end, who cares? A DN is a racing machine and top speed is only important relative to other DN’s, the rest is dust in the wind.

Cheers,
Eric

Speed is relative. 
#1.  people tend to exaggerate speed claims when their backside is mere inches from the surface.

#2.  The largest, fastest boats take time (and distance) to get to their top speeds.  D.N.'s will accelerate the fastest, and can also be pushed the fastest off the line.  In Maumee Bay where course lengths rarely exceed 1  mile, Renegades, stern steerers, nites, etc just cannot get enough speed before they have to turn a mark.  Unless there is Deep or sticky snow, the DN reigns supreme on the small course!  Also the DN is the most dynamic, with many different runners to choose from, different sails, and a modern carbon-fiber mast that will adjust to the conditions like and "automatic transmission" (credit Chris Clark for that analogy). 

#3.  I carried a Garmin GPS around for a few years, and did a lot of checking to find that MAX speeds are often erroneous.  Anyone who claims a speed over 60 on their GPS really needs to download the .GPX file and check for an anomaly.  often it is easy to see on a plot of the track where a track point is not where it should be.  Newer units are probably better at eliminating these issues, but all GPS accuracy is dependent on being able to lock in on as many satellites as possible that are in different parts of the sky for best angle resolution.  A GPS in your pocket or hidden under the back deck must compete with a boom, mast, wood deck, your arm, helmet, etc. to see all the satellites.  I can go on and on about this, but you get the idea that what comes out of a magic electronic "black box" is not necessarily the truth.

My observations:
As speeds exceed 40 mph or so, windage becomes the primary limiter.  Going up-wind in clean ice with 15-20 mph winds, you can hear what sounds like a jet engine screaming in your rigging.  Kind of cool, but you know that apparent wind howling up there is holding you back. 
Downwind, the apparent wind goes more in your favor and that is when the speeds can approach 60+.  Of course in racing it is also about VMG (velocity made good) so Max speed does not determine who gets around the course faster.

I know little about "bubble boats"  but it is clear that to create a speed-record machine you will have to design it to sail in perfect conditions and it will only excel in a small wind range.  Everything would have to be aerodynamically faired to perform at or near that target speed.

Great!  Thanks very much for your comments.