Need Advice

[mparent]

A new Raymarine st60 speed indicator was put on my boat. However, the location was changed to the back on the boat on a flat part rather than the front of the boat on the rounded part. The person who did the work said he thought it would be a better location but I cannot seem to get an accurate SOG reading should I move it back to where the original speed indicator was installed or is it a software or initiation problem?

[atoll]

it may need calibrating,or sender unit cleaning

[GordMay]

Presuming it's a sailboat, the transducer should be sited within the clear water
flow areas forward of the keel.
It seems as though he may have located it more appropriately for a power boat.

See page 11 ➥ http://www.raymarine.com/SubmittedFi...81037_5www.pdf

[Pelagic]

When you say SOG I am assuming that it is interfaced with a GPS to give you that information on the display?

If not, the transducer is giving you only speed thru the water and will not agree with your stand alone GPS.

[Cavalier]

Originally Posted by mparent

A new Raymarine st60 speed indicator was put on my boat. However, the location was changed to the back on the boat on a flat part rather than the front of the boat on the rounded part. The person who did the work said he thought it would be a better location but I cannot seem to get an accurate SOG reading should I move it back to where the original speed indicator was installed or is it a software or initiation problem?

Hi,

Both Gordmay and Pelagic raise good points questions. Do you own a sailboat with a keel or speed/motor boat? If it's a sailboat then the location just forward of the keel on centerline is correct, if it's a speed/motor boat then closer aft would be more appropriate (for when your bows lift). Trying to match your speed-through-water speed with a GPS (SOG) would not be appropriate. If you do have a gps installed in the network your ST60 is attached to, and the display is showing an incorrect SOG (compared to a handheld GPS) then this has little to do with the speed transducer. Your speed-through-water tranducer reading is affected by currents and leeway etc so is relative to the position of the water - your GPS is telling you your actual speed relative to a fixed points on the earth.

Phil

[jeremiason]

The only other point is... If you are actually taking about Speed through the Water, you should calibrate the unit, if it is new or never calibrated. Preferably on a measured mile to be most accurate (Normally measured miles are around commercial ports).

You basically make 3-4 passes up and down a measured mautical mile telling the unit each time when you start and stop. It averages out the distances and calibrates to your actual speed through the water in knots. There are also other ways of calibrating speed with the ST-60, but this is the most accurate. For detailed instructions refer to your Raymarine Owners Manual.

The Speed over Ground does not need to be calibrated since it is calculated by using your relative position via GPS.