Tinny speed

[Graaaazor10]

Hi guys, we recently picked up a 2003 Quintrex dart 3.75m w/ 15hp yamaha 2 stroke outboard. We had the motor serviced and its running fine however only getting around 15-18km/h max no matter conditions (+2people) around the semi protected waters of Adelaide.

Is this normal or should we be expecting to get into the mid 20's at least? Cheers

[ellicat]

That's probably not far from normal. Perhaps a little on the slow side.

You could improve that by evening out where you put the weight in the boat assuming you have a driver, battery and fuel tank right at the stern ?? You could play around with your prop to go faster, but the tradeoff would be it would be harder to take off quickly and get on the plane.

How long is the Dart ?

[Graaaazor10]

3.75m.

Was curious as we have had a couple similar if not smaller powered boats flying past us

[kmcrosby78]

How big are the people going in it? And does it have floorboards as that all adds to the weight. I assume it's getting up on the plane OK? I don't know speeds (ie. what it should be doing) but if need be, you may need to get it compression tested to know if it is operating to capacity. But try shifting weight around like @ellicat suggested. Also, I assuming it's not taking on any water? Reason for asking is my old tinny used to take on a bit (pinholes that I rectified) and it certainly made a difference.

[Hweebe]

My question would be is it getting on plane.

Secondly have you trimmed it right to reduce drag once you get up on plane?

But for a 15hp plus two people i'm not expecting much more speed.