To take a sextant noon sight you first have to figure out when the sun will pass over your meridian. It is good enough to work it out to the…
How it works
How it works: Yacht Radar
To utilise radar properly it’s imperative that you learn how to interpret the information displayed. Many objects produce such a poor echo they don’t show up on the screen. Fixed…
How a seawater pump works
The water and oil seals on a water pump shaft will eventually wear with time, leading to pump-shaft corrosion or loss of engine oil. A daily check of the water…
How a cutless bearing works
Most boats have a bearing at the outboard end of the propeller shaft that supports the propshaft. Generally this ‘cutless’ bearing will be made of rubber which will, over time,…
How a yacht’s hull fittings work
It’s unfortunate but true that the hull on any vessel will have to have some holes in it. This will usually be for the wet exhaust, the stern tube, and…
How do boat propellers work?
A propeller is fitted to a vessel so that the power from the engine can be transmitted, via the gearbox and shaft, into the water at the aft end of…
How it works: Yacht stern gear
Astern of a yacht’s gearbox you will find the coupling that connects the power output shaft to the propeller shaft. The propeller shaft itself is usually made from a mild…
How it works: Marine gearboxes and clutches
The gearbox on a marine diesel engine has three purposes: to reduce the maximum speed at which the propeller rotates; to enable both forward and astern rotation of the propeller;…
How it works: lubricating engine oil
Lubricating oil in a marine diesel engine fulfils several functions. Whilst lubricating the working parts of the engine in order to reduce friction and wear, it also cools the parts…
How it works: the boat alternator
Engine power relies on a healthy boat alternator. Callum Smedley shares how to keep it running smoothly