SeaRoader

The SeaRoader was designed by Mike Ryan, a British builder of amphibious cars, as an affordable, multi-role amphibious workhorse. Ryan's earlier creations included the Ryan Streamline and the Z1A. The original SeaRoader was built in just 30 days. It was later developed into a production version sold by SeaRoader Cars from Tewkesbury, either fully built or as a chassis and body kit.

Design

Ryan kept the design deliberately simple. It has no complicated power take-offs or leaking seals, and is built around a very strong "external chassis concept" (E.C.C.) frame of 100 x 50 mm section. On land a Land Rover 200Tdi diesel, mounted behind the front axle for near-central weight distribution, drives through Land Rover axles with long suspension travel. In the water a completely separate, compact Beta Marine diesel with forward, neutral and reverse is used. Ryan said it burned only about a litre of fuel an hour at displacement speed. The production body uses GRP front and rear sections bonded to the chassis, with alloy upper rear sides and a tread-plate foredeck. The base model is 4.93 m long, 1.85 m wide and 1.91 m high, with a load area about 2 m long.

Sinking and redesign

During an attempt on a non-stop world record, timed to coincide with a local regatta, the development car sank after about eight hours. The fan belt had come off, and Ryan was working on it with the bonnet and inner engine hatch open while the car kept going at about 6 knots. A front wheel struck the underwater bank just as the wake of a passing cruiser washed over the bow, and the engine bay flooded. The car was recovered the next day. Ryan worked out that another 3-4 cubic feet of fixed buoyancy would have kept it afloat. The production SeaRoader therefore has composite front and rear panels and two central tub areas filled with buoyancy, so it should stay afloat even when full of water.