How Accurate Are Speed Wheels On Sounders

[Rich P]

Hi all

After Sundays social i took my boat back to the dealers to raise the motor on my new boat as it was spraying 6foot out the back.I also got them to put on the wheel and nav lights that Quintrex seemed to forgot. .

Anyway the dealer also changed the prop to a smaller pitch as the boat is heavier than normal.They took me down to test it on the river and to my surprise the speed went 60km at 5500rpm with 2 people and 65km with 1 person.So my question is how accurate are the speedos?

Regards

Rich P

[Ken A]

Depends on conditions how accurate they are plus how they are set up. I think GPS gives a far more accurate reading.

[Rich P]

Thanks Ken

What do you mean by conditions and set up? :confusuion:

The nepean was pretty smooth today.

And the wheel has been installed correctly that is from the instruction manual.

I will be taking a gps with me on the weekend so i will find out one way or the other.

Rich P

[Wetpatch]

Gday Rich p

I agree with Ken it depend on the set up on your boat how you trim it or how rough the swell is .The Nepean shouldn''t have caused too many problem with swell

My Allycraft also has a speedo that uses water pressure up a tube on the transom Idont trust mine to much as iv''e had the hose kink once and the bloody thing went crazy getting stuck or bouncing up and down like a taco I use a hand held Garmin 72 I also think the paddle wheel speedo set up on a transom would have to work better than mine:thumbsup:

Edited August 5, 2004 by WetPatch

[Guest Jocool]

Paddle wheels work well. Not as accurate as GPS. What you have to bear in mind is that they are affected by the current. So if you are standing still, at anchor, you could get a reading of say 6KPH. So if you are travelling against the same current, you could potentialy get an increase of proper speed by 6 KPH.

I had mine up to 345 KMH!

Was usint the hose at the time...got bored! :ohyeh: :nana:

[MazDan]

Yeah Joe is spot on correct..........the current has a big effect on them and whether your going against or with it.

I tested mine against my GPS one day and found it was out by mnore than 10%.

My sounder has a spot where u can adjust the % that your speed is out by but to be honest u just cant set it up properly as it would have to change when ur going in the opposite direction.

They give u only a very basic idea of what speed ur doing.

[Rich P]

Well just got back from the Para.Took the Gps with me.The sounder says 65km and the gps says 50.1. So thats how much they are out.

If i would have known they would be out by so much i wouldnt have got one.

Rich

[MazDan]

Rich, when u say sounder.............Im assuming u mean a fishfinder such as an Apelco which includes navigational stuff as part of its software???

I never take much notice of what speed Im doing anyways but the actual depth is something Im watching all the time............obviously specially in shallow waters or those I dont know as well.

[petert]

I have 3 speedos on my quinnie hornet. The standard quinnie speedo that is pressure fed from the leg of the yammie60, a paddle wheel that registers on my humminbird 35 matrix and a garmin gps that replaces the paddle wheel readout when the gps is connected to the sounder.

The guys are right, current will affect speed with the pressure type and the paddle wheel. I find that in a lake the speed read out of the gps is almost identical to the pressure readout of the standard quinnie speedo. I then disconnected the gps and calibrated the paddle wheel via the calibration setting on the sounder which displays speed, temp, barometer etc.

pete

[AdamK]

Rich

I''ve got a 475 centre console with a 40Hp at the back. my speed wheel show upto 80kms an hour some times and other times it shows anywhere from 60-70Kms.

I have re adjusted but still get the same readings. I think a GPS would be best for me. There is no way I could be doing 70Kms let alone 80Kms per hour

Adam