Are you sure your fuel consumption figures are correct. 110 NM at 75 gallons equals 1.46 NM/gallon doing 17 knots. Doing 12 knots you only got 1 NM/gallon. Is that correct?
BTW, the boat looks great!
Thank you
Pervious info is wrong, I wrote it down, but did not bring the info home with me.
Two separate trips, first trip was 75 gallons of gas running around 17 kt for an average in a light chop. Total trip per the gps was 66.8 miles so what 1.12 gallons per mile?
Second trip was 63 gallons at 33 miles so 1.9 and yes we were doing going between 9-12kt and it plows at that speed, water was nice and flat! But we were just going for a nice slow ride.
I'm still playing with the trim tabs and trying to find the sweet spot of comfort/speed/economy. The boat's trim tabs never worked before, so this is all new to me. If I push the bow about 1/2 down it picks up speed on-step and the engine rpm goes up about 300-500rpm without touching anything. If I push it down all the way the boat slows down about 2kt and we spay up over the bow and its difficult to keep on track as it wonders p/s easy and takes a lot of effort to keep on track. If I am on-step and retract the tabs all the way the bow rides up about 4' and we lose speed for a given rpm.
Right now to reach on-step fast I push the trim tabs all the way down, bring the engines to 3000rpm and once it gets up out of the water I back the tabs down 1/2 way and bring the rpm's back down to 3000 as once its up the rpm's will go to 3300-3500.
I would also like to know hull speed and plan a trip at that speed to see what kind of range I can obtain. I'm thinking 7-8? 33'x about 12'
The boat will plain at 12.5 but it takes a lot of power to stay at that speed, if I bring it up to 13.5 I can back down on the gas.
Looks like 14-15kt will be the sweet spot, up ontop of the water but still under 3k rpm ( about 2750rpm). Boat weighs about 17,000 dry (according to the yard travel lift). We then added 200 gallons of gas and 35 gallons of water + a family of 4.
33' long and powered by two chev 350's that have about 425 hours each on the clock since new, has velvet drives that were also rebuilt at the same time as the engines were replaced. The stock props are on the shelf at home, I think the PO added larger props but the lock nuts cover the stamping. The only reason I say this is my max rpm is 4000, some other egg owners claim they can get to 4500 rpm but we end up doing about the same top speed.
The boat has dual fuel scans but I am unsure of how they work, most often they are reading 1.5-2 (2000-3000 rpm), but the total gallons never adds up to what I use. For instance it says for our two trips combined I used 35 gallons.
I think this reads gallons per hour, not gallons per mile. If I floor it and run it up to 4,000 rpm's the fuel scans will read 10 per engine. All I know is I don't trust them at this point and need to find more info on them. As at 3000 rpms and 17kt I think its close to 22 gallons per hour.