Bangkok Riverboat

[Henri]

I've twice seen a preview of the Big Adventure (or whatever it is) show coming on TV tonight and the preview shows a wooden riverboat with a spike shaped bow which looks to me to be underwater when at rest or when the boat is in its displacement mode. The spike then goes airborne when the boat is in the planing mode and its L/B reduces to about 1/2 of its L/B when in displacement. Anybody ever tried anything like this?

[johnw]

I've been to Bangkok a number of times and paddled around in my cousin's sampoa, but I've never seen anything that has its bow under water. A sampoa has very low freeboard at bow and stern, with most of the freeboard coming from the coaming, but they usually don't plane unless you put a big sqat board at the stern. The usual hotrod boat on the canals is an almost flat-bottomed boat with a stepped hull and an arrow-shaped bow. Both types, if they are intended for speed, use the long-tail motor mount, where a long driveshaft is rigidly mounted to the engine and ballances the engine's weight on a mount that looks a bit like an oarlock. To steer, they swing the whole engine with a tiller. At high speeds, they pull most of the driveshaft and prop out of the water, so it looks like they are using the prop in surface-piercing mode. It's mechanically efficient and I've never heard of accidents involving the prop, but you can bet if someone tried to sell this setup in the US they'd be sued into submission in no time.