Paddlewheel Protection
- Thread starter lehighsail
- Start date
We used SOG vs STW to gage current. It was important in club level racing and important in cruising. In cruising we always wanted to be in the least adverse current and in the most beneficial current.
Yes, the paddlewheel is somewhat arbitrary. I think you can go deep into the menus and calibrate the speed. Want to go faster? You can. Nevertheless a clean paddlewheel can give reliable relative information which wanes the longer it is left to acquire growth.
Cleaning with a toothbrush while swimming is a great idea. I used to clean my bottom at anchor almost weekly and I'm surprised I never thought of that (Not that I don't have extra toothbrushes). I used to keep a toothbrush next to the blank inside the boat and some other cleaning implements. I had no concerns about pulling the transducer but was careful to make sure the threads were aligned properly to prevent gauling which could turn into a major issue. Sometimes slow is smooth and smooth is fast.
Yes, the paddlewheel is somewhat arbitrary. I think you can go deep into the menus and calibrate the speed. Want to go faster? You can. Nevertheless a clean paddlewheel can give reliable relative information which wanes the longer it is left to acquire growth.
Cleaning with a toothbrush while swimming is a great idea. I used to clean my bottom at anchor almost weekly and I'm surprised I never thought of that (Not that I don't have extra toothbrushes). I used to keep a toothbrush next to the blank inside the boat and some other cleaning implements. I had no concerns about pulling the transducer but was careful to make sure the threads were aligned properly to prevent gauling which could turn into a major issue. Sometimes slow is smooth and smooth is fast.
I use the transducer paint @Rich Stidger mentioned. It is a small bottle but it lasts many years. I’m not in a high fouling area but with the transducer paint I easily get to late summer before there’s any inaccuracy from fouling.
Not to say that the transducer is 100% accurate anyway - mine is mounted alongside the leading edge of the keel, so it is heavily affected by water flow over the foil. It reads much higher on starboard tack than port. I’ve learned to compensate for that mentally. I rely on GPS speed for most things but I still like having the paddle wheel to see the effect of current.
My B&G and Simrad instruments can be set to use SOG or STW for the true wind calculation. The problem with using the SOG setting for the wind calculation is that for some reason that makes all of my instruments show SOG on the Speed Through Water read-outs, which is annoying. This winter I added a Raspberry Pi to my NMEA network that can do the Ground Wind Speed calculations itself and not interfere with the display of Speed Through Water.
Not to say that the transducer is 100% accurate anyway - mine is mounted alongside the leading edge of the keel, so it is heavily affected by water flow over the foil. It reads much higher on starboard tack than port. I’ve learned to compensate for that mentally. I rely on GPS speed for most things but I still like having the paddle wheel to see the effect of current.
My B&G and Simrad instruments can be set to use SOG or STW for the true wind calculation. The problem with using the SOG setting for the wind calculation is that for some reason that makes all of my instruments show SOG on the Speed Through Water read-outs, which is annoying. This winter I added a Raspberry Pi to my NMEA network that can do the Ground Wind Speed calculations itself and not interfere with the display of Speed Through Water.
The paint I used on my AIRMAR speed transducer and old Datamarine depth transducer has been the MDR transducer paint that many others have noted. A few years ago I changed and bought a quart (life time supply) of the water based Interlux Aqua One self polishing bottom paint. it seems to work pretty good and last year was in for at least two months without cleaning. I have used Interlux Extra for my regular bottom paint everywhere else.
Years ago I asked one of the yard guys for a small amount of regular bottom paint in a plastic cup. Did the job. These days I just pull it and clean it.
I pull it whenever not used for a couple of days. I have a glass jam/confiture jar filled half way with vinager next to the through hull and put the paddle wheel in there when not installed. Vinager dissolves any grow that maybe present on the paddlewheel. When installed the jar is closed with the original lid and is ready for reuse.
