His life: Bring some slaughter on the water (explicit)

By BILL O'BYRNE - The Dominion Post

Here is an idea to make America's Cup yacht racing watchable: cannons, potato cannons.

Give every boat 10 of  them, a few cans of hairspray  as propellant, 1000 or so good-sized  spuds or apples, and let rip.

Suddenly, what is a bunch of incomprehensibly boring back and forwarding tacking duels become very exciting attacking runs.

The 20 or so on-board cameras, which previously captured the excitment of 15 people sitting on the edge of a boat or grinding away for seven seconds every hour, will be livened up immensely as they cower, while fruit and vegetables travelling at 150kmh smash across the decks.

Then, of course, there would be the inevitable retaliation . . .

Certainly, there will be injuries. Some nasty bruises, fat lips and the occasional death, but there will be glory, true bravery, and great, great television.

It won't be for the faint of heart. By jingo, no.

I was on the receiving end of a highly modified spud cannon made by the Waldmann-Moloney Creative Ballistics Team in Manakau, north of Otaki, last weekend. Never again.

In the nanosecond I had between the time 11-year-old Albie hit the igniter and the apple smashed into 1000 pieces by my shoulder, the only thought possible was that I had just made a terribly, dangerously, bad decision by going out only 30 metres instead of, oh, 300m.

Upon being coated in appley bits, I invoked the name of a noted religious leader and jumped some distance into the air.

The potato cannon has been around for a while, but the three lads who make up the creative ballistics team have been refining the concept since some fool, possibly me, first gave them William Gurstelle's Backyard Ballistics about four years ago.

Being backyard tinkering geniuses, Otto (14), Albie and Poldie (8) took an already impressive device, and have modified it into a modern machine of awesome firepower that would rake the decks of any yacht at a reasonably accurate range of, I kid you not, 200m.

Having developed a close relationship with Plumbing World in Levin, the boys made the latest version out of about a metre of 50mm wastepipe, pushed into a 100mm to 50mm adaptor, which goes on to 100mm end pipe with an end cap.

The igniter is a piezo igniter from a barbecue and the propellant is Budget Hairspray.

To get a better seal on the apples, which they use because seconds are cheaper than potatoes, they sharpened the edge of the barrel to better cut through the apple.

This gets rammed down the barrel, a second's worth of hairspray is applied, the cap is screwed on, and the igniter hit. There's a big whoomph, and the apple flies outwards.

How fast depends on a number of things, William Gurstelle says.

"A couple weeks ago, I built a gun with an eight-foot barrel (2.4m). (The longer the barrel, the faster the muzzle velocity and the further the potato goes).

"We aimed it straight up and it took about nine seconds for the potato to go up and then come down. If you crank through the physics using the one- dimensional particle kinematics you might remember from high-school science class, you'll find that it went about 120m straight up and had a muzzle velocity of about 190kmh.

Typical guns with one-metre barrels shoot about half to three-quarters that fast, says William.

The calculation is complicated and we could go through it, but it would be just as simple to go to his site, backyard- ballistics.com. It's all there.

The Waldmann-Moloney Creative Ballistics Team's modifications involve greatly increased speed, which would probably be better for the big boat races.

"Our second gun has the same barrel as William Gurstelle's, but our explosion chamber is 100mm diameter and only about 14cm long," Otto says proudly.

The result is something which could revolutionise quite a few maritime races, apart from the America's Cup.

There's the Sydney-Hobart race, the Fastnet, and even possibly the Lake Taupo under-12 dinghy sprint race and slaughter (just a working title).

Of course, ordinarily we don't fire these at people, houses, birds or animals.

Highly paid sailors are different. They're professionals, on expensive boats.

That New Zealand taxpayers have contributed funding worth hundreds of hip replacement operations towards.

So let's set the agenda for this century's sailing traditions and return to the age of projectiles. If we want it enough, it will happen, and I have three boys ready to start arming your vessel.

See the boys firing the cannon at Bill here (contains explicit language):