While visiting South Devon in 2016 we spent five days in Bigbury on Sea for a short holiday to visit Burgh Island which is 250m from the mainland. This island is approachable on foot at low tide, but at high tide a sea tractor transports passengers back and forth. This unusual vehicle was constructed in 1930, and drives across the beach with its wheels underwater on the sandy bottom while its driver and passengers sit on a platform high above. Power from a Fordson tractor engine is relayed to the wheels via hydraulic motors.
At the entrance there is a set of steps which is lifted by pulleys to allow passengers in and out, there are various seats, and the driver operating controls and steering is on one side upstairs.
I took some photos and promised myself that I would build a replica of this model one day, as I found it quite an interesting vehicle that I had never seen before.
So with not much to do on Wednesday 17 January 2018, I decided to have a go and start building this model. I started building the long circular tube which mainly holds all the wheels, steering and hydraulic and fittings for the struts to support the ceiling or loading platform. By late afternoon I had managed to build all that and all the supporting walls in the passenger area, mainly built with braced girders making the model better and more attractive than in the original vehicle.
On Thursday I started adding the roof, which I left partially uncovered so it is easier to see the inside, and I built a few rows of seats.
I fixed the rear wheels using a differential with some supports fixed to the main base of the roof and concentrated on making a steering system of my own design which works well and turned out better than I thought it would. I did not do any work on Friday but on Saturday I built the steps to the upstairs deck and also added the front loading steps which can be lifted once the vehicle is moving and the passengers are all in.
I added few refinements so that the model looks better than the original vehicle which is old and tatty. Instead of using a mechanical system to lift the front steps I fitted a crank and small pulleys so it can be done manually by pulling a string. Finally I decided to add a standard Meccano motor with reduction gears connected to the rear wheels via pulleys and elastic bands and a control system built upstairs where the driver controls the vehicle. The front steering system needs to be connected with a steerable axle so it can be operated from the top.