New Ice Speed Record 39.3mph!


Date: 3-26-06
Location: Squam Lake, NH
Boat: SK-1 Skeeter, Custom built Ice boat
Skipper: Jeff Brown US 206
Maximum GPS recorded speed: 39.3MPH
Session time: 2hrs 37 min
Total logged distance: 28.9 miles

Mostly cloudy
Temp: 42.5 deg
Winds: N 10-15+
Ice Conditions: Hard spring ice, textured with wet film,
considered “grippy”, but fast and many square miles of it.


I thought the year was quite over, after the prior week sailing just
south at Lake Wentworth, with very slushy and rutted ice from a long
season of hard use by traffic, snowmobilers, fishing derbys, ect.
Total ice breakup was soon expected as well.
My first experience sailing the SK1 was less than ideal on those
rough conditions and I thought I would need to wait for next season
to race across new black ice to realize the RC boats true potential.
But somehow I managed another trip north on a whim that I might just
find a better surface on a more remotely used lake.
My first stops were by several off-the beaten path locations around
Lake Winnipesaukee, but this lake has now gone to waste with the
slabs breaking up in many locations, open water leads everywhere, I
feared I would loose my boat into an open lead forever. I would
rather not even try to sail if this was all the ice I would find

I then moved more northward to Squam Lake, where I knew there would
be no remnant tracks from snowmobiles, as these are not allowed on
this rather remote gem of a lake.
I went to a location I had once ice sailed before on a Freeskate more
than 20 years ago. As I passed along the lake side drive I noticed
the ice was indeed in good shape, snug tightly to the shoreline and
the surface gleemed as if it were January ice quality.

Once I parked and investigated the surface, I knew I was in for a
great day. The ice had not even begun to slush out in the warm temps.
In fact it was the best ice I have ever seen in March! It was a
quality, firm, hard surface with a slight sheen of wetness, but the
ice grain was evident to also provide excellent lateral resistance.
What more could I ask?
How about the most beautiful vista of the White Mountains sloping
right down to lake’s edge? No wonder the site was chosen for the
movie On Golden Pond.
How about a light side /onshore wind of 10 mph and building!
The day itself was a gem to just be there.

I quickly rigged the boat, set the GPS and zeroed register, then I
took a photo of the GPS reading for documentation.
New for this session was a crudely made bendy mast, “hey why not try
something quick and easy”, were my thoughts when I came across the
bendy fiberglass rod found in a local hardware store at home.
At first I thought this was too bendy as the leech was sure to
collapse with the slightest bend fore and aft. Still I thought I
would try the simple device and learn.
Then she was off!
Right away I saw the advantage of the bendy mast working in my favor.
The boat accelerated, squatted low and stuck to the ice with such
efficiency and no hiking!
It was really ripping around with amazing control, from bursts of
speed to radical tight turns. The mast was bending out just about
perfect as compared to my full size DN experiences, this was indeed

The wind began to steady and I became more confident that I would not
send the boat miles out of range, so I began to really push it.
Soon enough I was posting 30’s, then 32’s 33’s with my curiosity ever
increasing that I could really get some decent speeds.
Then the perfect wind filled in to a steady 15mph and I paced the
boat over several peeling speed runs in each direction, a few I knew
were more than enough to be the best yet, then she sailed far off out
of radio range, thankfully I managed to round it up and stall into
the wind, more than a half mile away! The potential was there to send
it at least 10 miles away had I not taken precautions. It’s a BIG

I had a long walk for that pick-up, but when I checked the GPS it was
true, a new record of 39.3MPH was displayed and I knew that last run
had been the ticket! I took a photo of the reading while the GPS was
mounted. (See SK1 folder at Yahoo site below)

How about some more! The wind was building to 15mph and greater as
the clouds were clearing. I sent the boat into more pegging bursts of
speed, but by now the wind was really distorting the rig, way beyond
practical limits of this mast/sail combo. However the boat still
refused to hike, instead the mast just kept on bending to nearly
2/3’s its normal height and bowed out to the leeward runner!
Yes, at this point I thought a bit too much for bend. I did not have
a smaller sail and the boat was clearly out of control bouncing all
around, skidding, sail inverted. It was survival in winds gusting to
Then it finally took the overdue and expected crash, skidding and
toppling to break both rear runners and possibly the steering
servo?..all in a good days work, I say!

I packed it up and went on my way home, thinking about the next steps
in design; the next mast, the new runners, the new sail design of
which I have so much to do, and learn, and then next year we shoot
for the 40 barrier! Ohhh, so close.:crazy:

But one thing is certain in my observations now more than ever.
The bendy mast concept is now a proven performance winner for control
in RC models as it is with the big boats! I would never have had the
same control of the boat with a rigid/stiff mast which would have had
the boat hiking and skidding as my experiences from weeks prior with
the model showed. In fact, I had this RC boat performing so close to
the full sized boats in every way that an untrained onlooker may not
even know the difference!
Today was groundbreaking proof to me that bendy masts are here to
And there is so much more to do.

Sail fast, take risks…:batman:

Jeff Brown
US 206

PS: Pictures posted in SK1 folder.

[b]WaaHooo [SIZE=4][COLOR=Black]Way to go Jeff :jump:

[/b][SIZE=2]Well done mate, what a great effort.

I can only imagine the thrill that must have been. :nuts:

Keen to hear more details of that mast.

Could it be applicable to Land yachts?:what:

Congratulations from New Zealand.



Good going Jeff!!!

We look forward to seeing more of the SK-1



Here is a decent study diagram of the mast bend concept and my experiences with it during the record speed run!
The bendy mast is based on a full size DN Iceboat concept.
Lots more to do! :shades:

Open PDF file and save local to your PC, then you can use “VIEW”/ “Rotate conterclockwise” to see in landscape view.

Words are not enough to explain this complex and unique approach to sail/mast design which has proven hands down sucsess for the DN class of iceboats.
I believe I am the first to experiement with such a radical mast for RC models.:watching_

Go to:

to see the real full size action of DN bendy masts!

Jeff Brown
US 206

Jeff -

Your analysis and info on mast bend was interesting. What is of major interest, is how the mast is kept out of compression and how it doesn’t seem to want to rebound and then rebend. I don’t want to get off into big-boat theory or applications, but I had noticed on my big cat - similar characteristics of an ice boat related to apparent wind - that when diamonds were loose beating in strong winds, the aluminum mast would get the “shakes” as it went into and out of compression. It could be cured by bearing off a bit and loading up the mast, but I was not able to determine the cause. … Too much mast material stiffness? Foil shape of mast which was rotating into wind and I was sailing at that point when apparent wind was moving back and forth? Still too much diamond tension to prevent mast from really bending off in gusts? At the time (1983) I had even discussed with Jan Gougeon and Mike Zutek as to possible cause. Now admitedly, a lot has changed since then in theories and in composite materials, and they were of opinion I might be running diamond too loose. To this day I have never found out - but sure isinteresting when I noticed your comment about mast tip “wobble”.

Any further insight is appreciated. Regards, and thanks for sharing.

Hello Dick,
I like your experiences with the multi hull.
Your aluminum mast certainly wanted to ?bend out? and the diamond stays prevented this. However if you had slacked the diamonds, or removed them entirely, your mast would have bent then broke. Aluminum can?t ?cycle? like a composite stick is able to do.

I owned a Tornado for two years before giving in to Windsurfing. Now I am one of the radical sailors you rarely see out in 40mph storms! Lots of information to possibly incorporate with windsurfing rigs too.
I also ran a Windsurfing sailmaking operation for 12 yrs full time, designing and building every sail under the name JB Designs, JBD, but now just make my own gear not for sale. I plan to develop many sail ideas with the RC model.

You touched on a very important issue with the bendy mast used on my SK1 model.
First, some basics of DN mast design (for those non informed):
On a full sized DN, the mast IS under incredible compression, hulls have snapped under the mast base. The DN rig can be controlled with mainsheet tension countering the headstay tension, where the two forces drive the mast down. But due to the SS bend built in, the mast will bend out to leeward, even when stationary, sheeted in and no wind loading.
The purchase required to sheet sail is at 5 to 1 blocked. The entire boom is sheeted in and lowered to deck with a forward boom gooseneck block acting like a cunningham at the mast.
Once a DN is powered up and the mast ?popped out? the sheeting forces to keep it there become quite controllable. You sheet in a few inches and you watch the mast flex easily down low as designed. This hands on control can be very finely tuned for mast bend efficiency.
This may seem like a loss of power, but it?s a gain in control, which allows more exertion on the whole rig, hull, runners ect, to sail the boat harder and faster.
All I know is it works great and is common, current proof of design.

Relation to RC boat:
All the bend I was getting with this particular crude fiberglass rod mast was due to wind loading and not so much mainsheet/headstay tension.
The sail servos are simply not powerful enough to take advantage of controlling the mast bend. When stationary, I sheet the control in and hear the unit whinning with little bend occurring in this softest of mast.
Therefore, the forces at hand to bend the rig out as far as it went were mostly due to true wind loads, combined with apparent wind loads. Stay tension becomes increased due to acute angles when mast hound lowers and this adds to the mast compression to some degree as well.

As you observed in my diagram, the overbend mode began to cycle the mast into compression, then would rebound only to bend out again. And then the perpetual ?wobble? tip took the entire boat and sail eventually out of sensible control.

The servo/ mainsheet force required may become a significant hurdle to overcome.
I would rather have a much stiffer mast overall to control this overbend mode, but the servo is not capable to produce enough torque to reach the mast bending I wish to achieve.

As I took the advice of other RC modelers, I used the Futaba Sail Swing Arm servo. I assumed I would not need the added purchase power to block rig the sheet, so it is working 1 to 1 ratio, which is not enough by a long shot.
If I start adding the purchase blocks, then I loose the total distance range the sheet needs to ease the boom , for the boat?s range required to work at all. I think.
The arm only takes up 3? of line, which I know I would need 3 or 4 to 1 ratio purchase advantage for the kind of torque required to bend a mast. This leaves less than an inch of working range for the boom. Is that enough?

This also brings up the possibility to get a sail winch type servo, but I see the ?take up rate? is quite slow, but continuous, non linear. It may not be great for quick adjustment racing, but it would prove helpful for full powered speed sailing. I do see Futaba sells the sail winch which is nearly double the torque of the swing arm. So, possibilities are there to try.

Any thoughts on servo power please share because I am lacking knowledge in this department.
I am interested in learning how many different ways I can take advantage of mainsheet tension with the limits of servo power available.

Overall, I am starting out with my new boat by first testing the very stiffest mast I would want, followed by the very softest!
I am confident I will work back from the softest design to find the medium.
The stiffest mast by comparison was hiking and skidding the boat beyond any sensible control.
If I follow the logic of DN iceboat mast designs I?ll find the right ultimate combination for the RC model. I can also see having more than one flexible mast for various conditions. And sails?, well YES, I will probably have WAY too many of those?..

The research continues?..:drink:

Jeff Brown
US 206

Jeff, I have linked to the Guyatt winches from Australia.
These come in two basic models either of which can pull four wheel drives out of the mud.:diablo:
They have travel distance which can also be programmed and I have no doubt that with the appropriate drum the speed will be OK as well.
Rob Guyatt is totally approachable and enjoys nothing more than cooperating on a project such as yours if you need extra speed or travel or grunt.

Your data is being talked about here and the brain is whirring away with ways to use your information on all sorts of models.:idea_125:

Congratulations, Jeff!

I was surprised to hear that you set your new record on Squam Lake, as I live very nearby in Moultonboro. Wish I had been there to see it!

I tried to get a couple of our S1m sailors interested in ice boats this winter, but not enough enthusiasm. Maybe your success will change that and generate some interest in this area.

If you come back this way, let me know, and I can act as your official witness/photographer. I could probably talk my wife into letting you stay with us if you need a place to crash for the night. Of course, you’d have to be prepared to answer a lot of newbie questions!

Bill Hagerup 603-284-6642