1986 20' SF with a Merc 150 4S performance numbers

[Jared]

I looked around a lot for numbers like this when I was looking for new power, found a lot of people asking similar questions but a lot less that got a detailed answer to it. Maybe this will help someone with their decision making down the line. I know lighter power is preferred on these hulls and I would tend to agree, but since I was doing all the work myself I tried to take a lot of steps with rebalancing weight try minimize the change in CG. A little information about the setup in general:

- 1986 20' Seacraft SF
- 2019 Mercury 150 4 stroke (25" shaft)
- Engine mounted in middle hole
- Mercury black max 13 1/4" x 17p 3 blade prop (p/n 48-77344A45)
- Original floor height
- Fuel tank reduced to 52 gallons, rear edge of tank slid 30" forward of front edge of in floor livewell compared to original tank (70 gallons)
- Factory center console replaced with a 10" narrower custom one with a cooler in front instead of cooler/storage seat molded to front of original console.
- Rear edge of console moved 6" forward of rear edge of original console location
- 2 batteries moved inside console from rear hatches.

Boat sits in water with water level touching deck scupper outlets in transom. I have check valves installed inline for the deck as well as the hoses crossed port to starboard so it minimizes water on the deck if someone is standing in the rear corners.

RPM/GPH/MPH
2500 3.5 15.8
3000 4.3 23.7
3500 6. 28.8
4000 8.2 32.4
4500 11.2. 37.2
5000 41.0
5300-5400ish 44.8

all the numbers up to 4500 are with 2 adults and 3 kids on board, 40 gallons of fuel. 5000 and up were just me, half tank of fuel. I have to scroll through my smart craft gauge to get to GPH, I didn?’t want to take a hand from throttle and steering to do that at that at those speeds.