CONTINUOUSWAVE

Ignoring any weight increase, going to 70-HP from 40-HP should increase the speed of a moderate V-hull boat by a factor of (7/4)^0.5 or 1.3-times. If the boat speed with 40-HP was 25-MPH then the expected speed increase would be to 25 x 1.3 = 33-MPH with 70-HP. The 70-HP engine very likely weighs m...

Was the engine installed by a dealer or did you do it yourself? I would ask the dealer to borrow a different prop. Something is very wrong. A Yamaha dealer should have a Yamaha prop available. Look at the list I posted. You should be able to hit 40 mph easy. For the time being, remove the tabs to e...

Have you completed the required 10 hour break-in procedure as detailed in the manual? If not, complete the procedure and then check performance. Please go back and re-read my post. Prop size/performance is NOT universal across brand/model. A Turning Point aluminum x by 17 will not run the same as a...

I feel like [the boat speed with this boat-engine combination] should be at least [35-MPH] with no debate. Please explain the basis for this assumption. I don't have any argument with the stated speed. I am just curious how you cam to hold this opinion. Just from researching similar boats. I previo...

Results of testing a 13.25 x 17-pitch aluminum [Turning Point] propeller were not good. Boat SOG was 26-MPH measured with GPS receiver and WOT engine speed was 4,100-RPM. I was unable to measure current or wind speed, but I’m on a lake so current is not much a factor. When I tested the boat today th...

[The engine mounting height] currently [is one-hole up]. Will [a change to engine mounting height two-holes-up cause] much performance difference? I want all-round performance, not just top end boat speed. I ordered a turning point 13.25 x 17p aluminum three-blade to test before buying a stainless s...

I just re-powered a Dauntless 15 with a new Yamaha F70. I used the [Turning Point] propeller wizard for a recommendation. It gave me the options for a 14 x 13 or 14 x 11 propeller. I bought the 13-pitch to test first. 14 x 13-pitch test run: [boat speed was] just over 30-MPH and [engine accelerated ...

Thanks for posting the boat's federal hull identification number or HIN. As you may know, the HIN contains information about model year. I decode your boat's HIN according to the method I describe in the FAQ answer to Question-2 as follows: BWC = the manufacturer identity code (MIC) for Boston Whal...

Thank you for the responses!! I’m going to go ahead with the repower hopefully early this year. I’m not interested in selling. Jim-I have had the same trouble locating information on any 1993 15’ Dauntless. I typically only find the years 1994-1996 for this size. My biggest concern with this is I wa...

Last year I purchased a 1993 Dauntless 15 powered by a 2004 Yamaha 40-HP carburetor engine. I had no problems with the boat or engine, other than the boat was under-powered. There are stress cracks running along the [topsides] of the gunwales, [but they are] cosmetic. There is one soft spot on the h...