THUNDERCAT RACING INTERNATIONAL CHAMPIONSHIP

UKOPRA ROUND 5 – Littlehampton Beach, West Sussex, UK

Myself and my co-driver are TEAM 18 – SHARKY

We race an Aquarius Aquacat with a Tohatsu 50hp 2-stroke motor.

It has had a substantial amount of work done to it to get it ready for racing. The motor is 22 years old! But that’s the beauty of 2-stroke engines, they just keep on going and going as you can easily rebuild them.

When I bought this motor second hand a few years ago it ceased on me within a matter of weeks, as the previous owner did not take care of it. In fact we found barnacles inside of it. Thankfully my co-driver is handy and was able to un cease it shortly after it happened.

Once we cleaned it up and replaced some gaskets, we got it working again, but it was then sent to Jeff Purves at Ocean Racing to get a full rebuild and mods for racing.

Some of the work that was done:

. Exhaust porting
. Bigger exhaust
. Head skimmed
. Welded crank
. Rev limited disconnected
. Carbon reeds
. 128 Jets
. Racing engine mounts

The motor actually came with a lightened fly wheel without ring gear, but as that’s illegal in the race, I had to have a stock fly wheel fitted.

It was around £2000 worth of work and parts that needed replacing, and at the time it the Coronavirus was in full swing, so getting parts was an absolute nightmare. A lot of the parts we had to source second hand, just so that we could get it rebuilt in time for racing.

Generally in Thundercat racing, you will need a few props. We have a 13 pitch semi cleaver, which we rarely use, but is great for Surf events. We currently borrow a 14 pitch prop, which is a great all-rounder but can handle rough conditions but still has low end bite. The main prop we use is a 15 pitch, as this gets us a decent top speed, but also grips in hard turns, it doesn’t let go like the others. The sacrifice is losing the hole shot though.

You can see the prop on the left has been worked as oppose to the same prop on the right. Prop on the left is a 14p and prop on right is 15p but you get the idea. Its around £250 to get the prop shaped, thinned and cupped ready for racing.
15p Solas and 14p Vengeance worked.JPG

Racing started at 11:30am on the 13th August 2022 as this was 2 hours before high tide, and gave us the maximum amount of time in the ideal conditions.

With a rare 15mph South East wind for the first 2 hours it was nice as the sea was kicking up a bit, and these Thundercats love that, perfect for skipping across the water.

After two hours the wind dropped and the sea was fairly calm, which to be honest wasn’t great for us as our boat is significantly slower on the flat. This can be down to set up, motor height off the transom, size and type of prop as well as other things such as oil ratio, type of oil, any fuel additives and engine mods.

LeMans style beach start, where the co drivers line up and run toward the boat once the green flagged has been dropped. The driver is not allowed to put the kill cord in until the flag is dropped, and is not allowed to jump into the boat until the co driver has both hands on the boat. The driver is not allowed to start the boat until both co-drivers feet are in the boat.

Now, I'm going to say it and I will sound like a bad sport, but 1 team (I won't name them) were getting away with jumping in the boat before the co driver was there and then starting the motor before the co driver was fully in the boat, and thus getting an insane head start on the rest of the pack. It didn't go unnoticed by the crowd, but sadly the race officials were looking elsewhere every single time.

I did see complaints being made by other teams and I believe some action may have been taken, but what I am taking away from this, is next year we will do as they do.

We know that the two winning boats were running Nitro and also 100:1 oil mix, which we didn’t know before the event. We now know so next time we can do the same. I think we’ll choose thinner gearbox oil next time too for less friction…lots of things to consider.

Here are some onboard shots I got from my Go Pro camera:

My co-driver has to get down and tuck in for the corners to keep the boat from flipping and also ensure we get a tight corner without losing speed.

Once the corner is done he has to get back ASAP so that we can get air under the boat and accelerate again. Its a fine balance though, if we are too far back you can get too flighty and flip backwards.