Overall range of Seacraft 18

[eggsuckindog]

If you have the ability to figure your mileage just fill up before and after - should be close and 2 mpg is probably pretty close anyway, thats kinda what I use too.

Using my Flowscan, gps, fuel gauge and the basic fill up before and after, I am getting an average of 4mpg with a 150ETEC on my 20SF - cruises at 3800-4000 and 36-40 mph. I say this because I had a 175 carbed Yami - 1990 before I got the ETEC. Using the same methods, I got about 1.5 mpg with it on the same boat.

[Fr. Frank]

With a '92 carb'd Mercury XR4 150, actually dyno tested about 190hp, I used to average about 2.2 to 2.5 mpg on my 20' Seafari. My bet mpg was a trip from Marathon to Key West in Florida Bay, where the entire trip was on plane at optimum cruise speed of 27 mph, and I got a little better than 3 mpg (3.04).

I now have a lowly 90 hp Mercury Optimax on the back of my Seafari, and I average 5.1 mpg at 24 mph, and my best is 5.4 mpg on a run from Homasassa to Cedar Key and back.

Oh yeah, I have Pettit Trinidad bottom paint for extra drag.

[Ryank]

5.4 is awesome how does she move with some weight in her?

[Fr. Frank]

The 5.4 mpg was with the bimini top down, and just two people. Loaded with 6 adults, it planes in about 6-7 seconds, and has a WOT of only 30 mph, cruises at 22-23, but the rpms jump by 200 to hold that.

My prop is wrong pitch to run fully loaded. Max rpm with just me is 5200, max with 6 adults is only 4850. Recommended range is 5000 - 5750. My opinion on propping is that I should be able to turn Max of Max at Max for safety reasons. That means I should be able to turn the max 5750 of the maximum rpm range with the boat loaded at maximum weight. So with full fuel and 9 people in the boat, I want to be able to turn 5750 rpms at optimum trim.

I need a different prop, but haven't found the right one. I currently run a Trophy Plus SS 4-blade 13.25"Dx21"P. I need to drop that at least to an 18"P, but my local dealer hasn't got one, and since I've had this prop over a year, won't trade me for a new one, but offered me $250 in trade toward one ($650). I've had this prop over a year because he told me just to hang on to it and he'd trade when he got an 18" or 19" in stock.

[McGillicuddy]

Fr. Frank, That prop info is interesting. I'm surprised you can turn a 4 blade 21p SS wheel so close to target with a 90hp on the Seafari. I didn't even bother testing a 4b Trophy plus last year because it was a 17 or 19 pitch and I was barely reaching the target rpm on my 115 I-6 with a 15p black max...should have given it a whirl...might have to see if he's still got it.

[Fr. Frank]

Gillie, my gear ratio is 2.33:1 That's how I spin the higher pitch.