Hello, the thru hull in the engine compartment , I’ve been told is for a Zinc Anode that is connected to another on the prop shaft. It is a Macwester 26. What kind do I need and will it keep the water out. I have attached a picture and indicated it with blue twine. I can see through it so it seems to me that it will let water in when I put it in the water. There is only a wooden block with holes in it. Thanks in advance Michael.
This should have two anode fixing bolts in it holding an anode on the exterior. These are special bolts which enable you to fit new anodes (when needed) without changing the bolts. These bolts have a long thread on the inside which you put wires on to, which are wired to the engine, the coupling, shaft and rudder fittings. This prevents electrolysis on external metal fittings.
Chris Nixon – Technical Officer – Macwester Owners Association
On my Moody37, which replaced my trusty MW 27 a couple of years ago, the anode, with the two special bolts is connected to all metal parts in contact with seawater throughout the boat: all skin fittings, seacocks, rudder shaft, engine, prop shaft tube, etc.
If your mooring is in an estuary, or marina where there is brackish water, don’t forget that an aluminium, rather than zinc anode is recommended.
MG Duff are generally recognised as being good quality, see extract from their catalogue in the photos.