How Fast Are You Going???

[Tezza985]

Got a 15hp Tohatsu pushing a 3.9 tinnie, and without having a GPS or speedo just want to find out how fast or slow the boat is travelling in order to get some idea the time it takes getting from A to B??

Is there a way without borrowing a GPS and testing the boat out over a varying rev range with X amount of weight on board.

Tezza.

[Zeeke]

Guesstimate?

or, just go to a river with a main road that runs along it, go as fast as ya can next to a car, then guesstimate how fast you were doing compared to the 60kms or so he's doing.....

Tim

[philip_thomson]

what you might be able to do is find an area that is 1.8km long (a rounded nautical mile) and then get a stop watch and just keep going along there at different rev ranges and you could do a few sums to get the speed. apart from that no idea

cheers philip

[ba229]

to figure out how long it takes to get from a to b use a stop watch ;D

i've no idea mate but my 12ft brooker with 15hp goes 38km/h WOT with just me and 35km/h with a passenger.

[Chrisso]

Only one thing with your idea Tim, the motorists may not always abide the speed limits. ;)

[Tezza985]

Hey Ba229, Was that timed over a set distance or did you use a GPS to get your speed?? and thanks all you guessmates.

I suppose i shall just have to time myself or buy a 2nd hand GPS !

Like the racing the car one though, but might have to tell them to slow down. Tezza.

[ba229]

GPS mate. it is an accurate speed as stated above.

[jeffo]

speed=distance/
time

;) back to grade 11 mathematics and you should be able to work it out!!

[phewy]

Yes it is easy to work it out Jeffo, but working out the distance in a boat without GPS is not. Suppose if it was in a river, you can measure distance with a car from point A to B, mark them on the bank and go back to your boat and then time it. Hard to do in open water but. [smiley=2thumbsup.gif]

[PinHead]

go down the Pin..measured mile in the southport passage. It runs along Woogoompah Island.

[phewy]

How bout just asking another boatie with speedo or GPS (and able to match your speed) to go along side of you for a distance, and get the speed reached ;)

[eggbeater]

Be careful if you go off your speedo reading as they are rarely accurate.My X85 speed reading uncaibrated (out of the box) for instance reads 66 KPH whilst my GPS is reading is 47KPH.