Speed Indicator

Chopppywaters · 17 August 2005, 22:42

Dunno if thats the right title but what is the most accurate...device to calc your speed? On my current boat we have a fishfinder (which doesnt work while we are moving) and a little wheel that supposably tells us the speed of the boat but at WOT (wen our fishfinder did work) it only says 20 mph tops and i know we've gotten it to around 45mph so......

Richard B · 18 August 2005, 01:29

GPS - just remember that it will show speed over the ground (SOG) with no allowance for tide.

Swifty · 18 August 2005, 10:26

Quote:

Originally Posted by Chopppywaters

Dunno if thats the right title

Its called a log. It measures speed and distance travel through the water.

Quote:

Originally Posted by Chopppywaters

which doesnt work while we are moving)

Check the transducer is below the hull so it is still submerged when on the plane and it is getting a clean water flow over it.

Hope this helps.
Tim.

Chopppywaters · 21 August 2005, 17:22

swifty do you know where i could find this transducer...is it in any certain area of the hull?

Swifty · 21 August 2005, 19:39

Choppers,

Sorry been out playing instead of surfing.
Transducer would normally be on the bottom edge of the transom where it meets the hull. The log usually has a thing that looks like a paddle wheel and is usually about 1-1½ inches diameter made in plastic.

What make is it?

I have a NASA dual unit (log and depth) which I have to say is pretty hopeless. It has a through hull paddle wheel which I managed to mount on the transom/hull line. Not too bad upto about 15 Kn, then just about shows 20 ish Kn when i'm doing 30+.

And the echo sounder cannot be relied upon over 10Kn. Again the mountings were through hull and meant for yachts that only do 10Kn max.

ATB.
Tim'mers.

Jizm · 22 August 2005, 04:25

Quote:

Originally Posted by Chopppywaters

Dunno if thats the right title but what is the most accurate...device to calc your speed? On my current boat we have a fishfinder (which doesnt work while we are moving) and a little wheel that supposably tells us the speed of the boat but at WOT (wen our fishfinder did work) it only says 20 mph tops and i know we've gotten it to around 45mph so......

Ah, snap! I'm gonna make a rig to experiment with the position of my transducer on the console. Saves drilling lots of holes and and you can fiddle about while some else pilots!

boatbuoy · 22 August 2005, 11:07

Alternatively:

Come to Southampton, run along side our boat, we can tell you when you reach 32knots, then its anyones guess as you out run us.

Either that or come to Southamton and run the measured mile?

Jizm · 23 August 2005, 02:11

where is this measured mile?

boatbuoy · 23 August 2005, 10:39

Quote:

Originally Posted by Jizm

where is this measured mile?

I'm fairly sure it is marked on the chart between Hythe and Cadland, think its on the Western Side of Southampton Water, but I'm propbably wrong, it's known to happen!

Jizm · 23 August 2005, 22:48

cheers, don't worry I will be sure to tell you if you are wrong!

Tim M · 25 August 2005, 01:44

Might have a pitot rather than a paddle wheel. These normally retract if they get bashed so you might need to push it back down into the water. Failing that check the end isn't blocked or the tube isn't being squashed anywhere.

Chopppywaters · 27 August 2005, 22:53

found the problem...i guess the paddle wasnt screwed in tight enough and it shifted upwards somehow...pprob during running Thanks for the help tho