Getting around Abel Tasman - tractors?!

Marahau is at the southern end of the Coast Track through the Abel Tasman National Park.  The beginning of the park is seen here in the distance.  It's a bright sunny morning at Marahau, the tide is mostly out and the exposed sandy flats a pretty rippled pattern - but what on earth are these tractors doing there?  Would it help if I added that I took this photo while sitting in a fully occupied water taxi?

An ingenious solution to the problem of low tide and launching the boats that take people +/- kayaks along the coast of the Abel Tasman - these tractors have delivered their loads and are ready to collect incoming water taxis.  The tractors start the journey at the water taxi headquarters.  They pull the fully loaded boats on the trailers down the road, onto the sand, and across to the water.  In they go...easy!

Launching a taxi.  Backing into the water quite a way - the trailer has to be under water, then off goes the boat.  It was difficult to get a decent photo, with the bouncing of the boat I was on - first on land, travelling on the trailer, and then on the water.  The other passengers - tourists and holidaymakers exploring the coast of the Abel Tasman - seemed to find the experience lots of fun.  I certainly did.  An unexpected bonus to add to all the other pleasures of being there.