Replacement log

[Athene V30]

I currently have a paddlewheel log that works when it feels like it if it has weed on it or not. I hate the process of lifting the log each time I have used the boat - I always imagine I am going to cross thread the blanking cap and sink the boat etc!

Before I go and test / replace the current paddlewheel arrangements is there a reliable means of measuring boat speed in a sailing boat without drilling a hole in the bottom of the boat or towing a length of line etc that can cope with slight weed build up etc?

I have a GPS but still want to know boat speed / distance through the water rather than measured over the ground.

Thanks in anticipation.

 

[Swagman]

Hi Peter,
I believe one can source sonic heads that measure flow twix sensors on hull and front of keel, but sorry - don't know where you'd get one from.
JOHN

 

[chasroberts]

Use the old method of a long piece of string with knots tied in it. Don't know the exact distance between the knots but someone will be along in a while who'll know.

Tied to a log (literally) or something that floats let the string run out between your fingers and count the number of 'knots' over a given length of time. Suitable extrapolation will give you your spped through the water.

That's how it was always done before mechanical speed measuring devices were invented.

Bit of a kerfuffle, huh?
Good luck

 

[hubert]

The 'sonic head' is available from Echopilot. (Based in Ringwood)