Boat Upgrading - Suggestions

Moonwalker · August 06, 2009, 22:17:35 CET

Great idea busu. Some "ppl" also told me that GPS reading is not accurate and should not be relied upon

stevea · August 07, 2009, 08:21:04 CET

Busu.. I guess you are right in a way... however rest assured that the way GPSs read velocity has a lot of embedded limitations.... imma for our purpose here I guess its ok..

busumark · August 07, 2009, 08:49:47 CET

the gps gives you the speed but it doesn t take into account the wind and curent velocity that is why you have to take 2 readings in opposite directions and than take the reading in between. sometimes there is a difference of more than 2 knots if you are going against or with the current

nivram017 · August 07, 2009, 09:02:19 CET

Its true that current and wind affect the speed of the boat . I have noticed this several times during our fishing trips. Considering this it is still difficult to specify the exact speed of a boat since there are a number of factors which affect it example wind direction, force, current, live load onboard etc.

skip · August 07, 2009, 10:52:57 CET

Quote from: Moonwalker on August 06, 2009, 22:17:35 CET
Great idea busu. Some "ppl" also told me that GPS reading is not accurate and should not be relied upon

Huh??? That's news!!!

Speedo's are totally inaccurate and should not be relied on, but not sure who told you that about a GPS!!!

Aside from a 1 or 2 sec delay they are the most accurate method after a Radar gun which is what tends to be used during boat tests.

Aircraft use it for navigation to display their ground speed along with a Pitot Valve to display their airspeed.

Our equivalent is the water speed which is measured either from a paddle wheel or simialr pitot tube using vacuum pressure from a water pickup. So the GPS displays speed over ground and the other displayed speed over water. Water speed should take into account current etc.

As busu said to get an accurate max speed you do opposite runs, but that's just for a max speed.

Moonwalker · August 07, 2009, 11:37:09 CET

Thats why I wrote that Skip. Afaik GPS reading is very accurate. But when I asked why my boat is not reaching certain speeds they told me that I should not rely on GPS reading...duh.

skip · August 07, 2009, 14:12:14 CET

Drop me a PM about the speed problems or you can open and we can discuss in another topic.

Moonwalker · August 07, 2009, 15:12:24 CET

Will see how it goes with the Trimtabs and then post new topic.

nivram017 · August 08, 2009, 11:35:36 CET

I have also been told that the boat engine is equipped with a trolling valve, can someonplease explain what is it exactly and whetehr fuel consmption will be affected?

Shaftbomb · August 08, 2009, 13:12:39 CET

Trolling valve - as the name implies is another throttle for use in slow speed, ex when trolling. Do not overuse it as you may break up the gearbox.