boat speed for Bluefin and Starcraft

I have seen several post on here and other places where boats similar to mine are getting 35, 40, maybe even 45+ mph. I am only able to squeek abou 30-31 mph out of mine with 1 passenger and WOT. Now granted I may not have the perfect prop, and I am still doing some fine tuning on the engine, but does 30 mph sound correct.

Points to note.... I do not have a tach(yet) so I don't know what my rpm's are. My mph numbers are coming from a cellphone GPS. The boat speedo only shows about 25-28 mph (I don't trust it anyway).

I know that there are a few on here that own the same or similar BlueFin and similar size Starcrafts. What speed are you able to get with a similar set-up?

Re: boat speed for Bluefin and Starcraft

Okay let me lend a few thoughts here and comments.....

The older Force motors I "think" (or remember ) that they were all head rated motors...... which really equates to 70 +/- hp at the prop.

The motor set up is critical...... critical on the mounting height and the trim angle. A few pictures of where the cavatation plate is ...in relation to the bottom of the hull at the keel.

Prop is the next item I would address...... what do you have now pitch and diameter.

You need to borrow a gps (maybe one from a car) which may be more accurate then the phone.

I also consider a tach to be very very important to establish if your motor is running at the optimum rpms.

You may be pretty close and a few adjustments are needed.... I would estimate you should be at least at 35 mph

Re: boat speed for Bluefin and Starcraft

Thanks Bob,

I want to get a Tiny tach or something similar. I question if the original tach for this motor is accurate. Instead of numbers, it has the sliding bar graph type display. I will have to see what pitch prop I have now. I am not looking for "top" performance, but if I should be getting 40 mph instead of 30, then something would be wrong. I also agree that a car style gps would be more accurate. I'll have to borrow my friends. Again, I was just looking for ballpark figures from others with similar style/size boats.

Re: boat speed for Bluefin and Starcraft

Just as a reference I have a 16.5' tin crestliner with a 60hp and loaded with 3 adults and 1 child + gear I can only get 28 mph. But the rpms are in the right zone so I figure thats as good as it gets.

Re: boat speed for Bluefin and Starcraft

Geeco I used to have a 91 18ft bluefin cc with a 90 force and never got it over 30mph

Re: boat speed for Bluefin and Starcraft

Yea, you should be getting better speed than that. I had an underpowered Starcraft years ago thet did better than that. As Bob mentioned, your RPMs are very important. With that hull design, you aren't going to want to run 40+MPH anyway.

Re: boat speed for Bluefin and Starcraft

I'm with Dave on the speed. I would like a bit more outta mine but I can't imagine doing 40. These style of boats are pretty light and sit pretty high in the water. Mine is a little squirlly at 28, and it catches alot of wind which makes it worse.

Re: boat speed for Bluefin and Starcraft

You should be able to see 35MPH. Probably not more than that with the Force. You need to get an accurate tach. greatlakesskipper.com has a ton of Force-compatible tachs. Prop your boat to achieve the the correct WOT RPM range. And maybe move the motor up. Do you have power trim?

Re: boat speed for Bluefin and Starcraft

Yes, I have power trim. I will check to see what prop I have on there now. I know it is aluminum, but I have no idea as to the size or pitch.

Re: boat speed for Bluefin and Starcraft

I have an 18 ft Bluefin with 75 Hp Evenrude, both 1984. 1 person, 18 gal gas & all my trolling gear (which is quite a bit) goes 33 mph WOT. (gps)

Tom B.
(LongLine)

Re: boat speed for Bluefin and Starcraft

I got my tach installed over the weekend and I also installed a tell-tale. While sitting on the driveway, I was getting 1000rpm's at idle (using muffs). I hope to get it on the water some night this week to get a idle rpm's in gear and WOT rpm's.

Unfortunately, I messed up my dash when cutting the hole for the tach. Oh well, I didn't like the entire look of the dash anyway and wanted to re-do it this fall.