After looking at the GPS, I am really not to worried about the crafts performance, and will be bringing you data on this shortly. The real problem is the ice surface.

Have a look at this video, which hopefully explains it a little better.

The problem with going fast is that you need to be able to support and transfer very large forces into the ice, and to do this the machine needs to be strong, and relatively stiff. When you need to absorb bumps over a range of speeds, this presents huge problems for a structure carrying high loads and a sophisticated suspension system is required. However, active controls are not allowed and there are also issues with the size and frequency of the bumps. The skate weighs over 50 kg and it needs to move at at a speed of up to 50 Hz over maybe 2-3 inches. To save confusing everybody, I won’t go on , but this challenge is nothing short of impossible. Imagine driving your car with steel wheels and no tyres over concrete speed bumps at irregular intervals at 120 mph.

Walking over the surface at slow speeds, you really don’t get a proper picture for the size and frequency of the ice bumps and I had been way too optimistic of what the natural flex of the main beam would accommodate. The end result is that the craft suffered a couple of failures during the first sail, that I was unaware of at the time.

Firstly the main sail bearing for the top section failed. This was a huge surprise and has performed perfectly for thousands of miles on land. It is a big industrial, self aligning machine bearing, that is rated for over 300 kg of axial load. The sail only weighs 25 kg, so well within design range. Secondly, the counter weight on the top section had bent very slightly down, meaning I could not extract it from the composite sleeve in the wing. This tube supports a lead weight in the end and was designed for dynamic forces of 10G (ten times gravity) to cope with any accelerations. However, it yielded.

Both these failures point to vertical accelerations of over 10G at the top of the mast, which is completely unacceptable. It felt rough from the cockpit, but not that rough!

Adding to the problems the lake had some more snow over the last day or two, which have exaggerated the drifts, extending the time that it will be out of action.

For now we have packed the craft up and will be repairing the two problems (easy fixes), but I am uncertain when we will be able to run again.

The bottom line is that to go really fast, the surface needs to be flat and this only happens at the start of the season, after first freeze and before any snow, or at the end of the season in March, when the surface melts, before the ice breaks up. My gut feeling is that the only opportunity is going to be after first freeze in December, but we will see. If the ice does get better this season, we will be back, but if not, then I guess I will be sitting by the lake in December while it is still water, waiting for the freeze.

If it was easy, everyone would do it, right?

Yesterday saw the first wind at Canyon Ferry, in the 2 weeks that I have been here. As a trough moved through the area, the winds picked up at about midday, to 15 mph, then steadily grew, peaking at around 30 mph by 17:00.

I got the Greenbird ready, tested the parachute deployment, strapped in the GPS and camera equipment (2 mini HD cams, one pointing forwards, the other backwards) and set off.

For all of these tests, you must remember it is essentially the same machine that I ran on land, both on tarmac in the UK and dirt in Nevada, so we have good performance figures to compare against. The initial acceleration was impressive and better than on land, reaching 40 mph without me even touching the sail controls. From then on a slight pumping of the wing sheeting pressure system pulled in the wing and we were off. But it very quickly became apparent, that the ice is just way too rough, despite my optimistic idea that we had enough room, it was not the case.

After a few slow circuits I was confident everything was working so pushed a little harder, peaking at 73 mph, but the ride was nothing short of ‘brutal’. Even with the ‘plank’ flexing nicely, hitting a 3inch ice bump at 70 mph in a yacht weighing 850kg, is a rough experience. The yacht bounces around, skips sideways very slightly while it regains its ‘edge’ then off again, pretty wild accelerations in all directions. Shakes the boat to pieces and is definitely not ‘fast’. The problem is that with these bumps every 30 feet, there is no let up. The further offshore you go the worse the bumps (actually old snow drifts) get, so I was confined to a narrow strip at the edge of the lake. However, even in these rough conditions, the Greenbird handled very well, good control of direction and power, no failures, which is a testament to the structure and overall strength.

This picture of my track, overlayed on the lake surface shows how little room we have to play with.

Track overlay

It was so rough, that BOTH onboard cameras malfunctioned, capturing only the first few seconds of each trip. This was a real shame because it was a pretty spectacular ride from the cockpit.

I was initially disappointed with the speed, as the yacht has gone a lot faster on land, but once the wind and GPS data was downloaded, I began to understand the numbers. Due to the confined space, I could only sail at close angles to the wind (into or away from it) and not perpendicular, which is fastest. The wind was coming from the prevailing direction at 320 deg. The fastest speed was 73 mph sailing at 51 deg into the true wind, is about 22 – 24 mph of wind. Now this is actually pretty respectable and proves record speeds are easily achievable sailing at the optimum angle to the wind of 110 deg. I will analyse the data over the next few days and present some performance predictions next week.

So what can we conclude from all this. Unless we encounter some unexpected grip problems at high speed, we easily have the performance to destroy all current records, but you do need almost perfect ice, which it is far from right now. Worse still it is not going to get better until they have a big thaw towards the end of the season (March), so we will have to make a plan whether we hang around for a little more testing experience, or realise there is nothing more to learn, until the ice is better, not decided yet.

I will be analysing the data over the next few days and will report back shortly. I also had GPS recorders on the other, conventional ice boats sailing in the same conditions, so it will be interesting to compare the data. Finally I will try to piece together the bits of the video that are usable, and get this posted.

The speed record: (note 30 Km sailed)

Greenbird speed graph

This is the wind record from our on site weather station:

Blue is 1min avg, Purple is peak gust speed

This is the nice ice, close in, and it certainly was smooth and fast in this area, but unfortunately it is just way too small:

Ice yachts on nice ice

The rough ice further out……

Bumpy Ice

Well after a few very cold weeks in Montana the lake at Canyon Ferry Dam is now properly frozen. A week or two before christmas temperatures were as low as -30 deg C, which builds ice thickness very quickly and is exactly what we needed. However, very soon after the freeze, it also snowed, which is exactly what we did not need! The general consensus from the locals was that the lake was then out of action for a month or so, or until the snow disappeared.

(Technical note: even a light dusting of snow can make the lake unusable. The moment it snows, it is not necessarily a problem as it is still light and fluffy, but it quickly drifts with the wind into sizable mounds, which then freeze into solid lumps, turning the smooth ice into more of a mogul field. To be able to approach record speeds, we need snow free ice for a minimum of 3 miles)

However, conditions have improved much sooner than we thought and after local inspection on New Years day, a significant part of the lake was clear and usable, with ice conditions improving all the time.

I therefore jumped on a plane and am currently on route to San Francisco, where the team van awaits. After a 1000 mile drive to the frozen north of Montana, we will set up on the lake, hopefully next weekend.

Many thanks to Dave, John, Jim, Dale and all the locals for the detailed weather reports over the past few weeks, much appreciated.

Time to make the sacrifices to the weather gods and hope the snow holds off for as long as possible!