Tuesday, September 27, 2011
Cargo Ship and Phinisi Boat Just Outside Manokwari bay
Last month I shot a cargo ship and a phinisi wooden boat just outside Manokwari bay using my camera Nikon Coolpix P500. I was amazed to see that the traditional Phinisi boat which was considered slower than the steel ship could chase the modern cargo ship. At first, the phinisi boat was behind the cargo ship. It was not moving on the water with sails but wit propeller. In fact, both of them were using marine screw propellers.
Later, the phinisi boat was at the front of the cargo ship. This is an interesting scene for me because most of us consider a wooden sailing boat like Phinisi slower than the cargo ship. In reality, it is faster - if it is equipped with marine diesel engine that drives a screw propeller. Another factor which makes the boat faster is her smaller block coefficient. The smaller the block coefficient, the faster it will be when moving on the surface of the water.
Wooden boats frequently experience water leakages in the stern tube area near the propeller. Traditional boat builder in Indonesia do not use lignum vitae as bearing materials. They have certain kind of wood that has properties similar to the lignum vitae. However, the wood has to be frequently replaced to prevent sea water from entering the hull through gaps between the propeller shaft and the stern tube bearings.
Modern design sterntube bearing uses seals and oil around tail shaft inside metal bearings with higher pressure to prevent sea water from entering the sterntube. - by Charles Roring