265 Express performance

[Diad]

So i have been trying to find what the performance of the 265 should be and haven't had much luck, so i thought that i would get something started. I just had my fuel tanks replaced in my 2003 with 2005 F225's (975hrs). I had the engines completely serviced (new fluids, plugs, thermostats, every filter changed, injectors cleaned) and now i want to understand the performance. Yesterday, i went out on a dead flat calm day in the Chesapeake Bay, 4 cold Natural Lights, and let her rip. The main tank is completely full (now 125 gallons) and the auxiliary tank had 40 gallons (now 115). Props are 17M with some blemishes. No fresh water, no ice, no bottom paint, no nothing else really.
I think that the optimal speed is 4400RPM's which was 33MPH burning 17-18GPH. Full Throttle was 6100 RPM's and 46mph. I trimmed as much as possible and just couldn't get any faster.

This being my first real ride, i truly enjoyed it. I just need to figure out all of these electronics that i put on and play some more.

I estimate in normal bay conditions of 2'-3' i should make 28-30mph with a similar load.

Any opinions on my numbers? What are you getting on your 265 and with what power?

 

[SkunkBoat]

4400RPM's which was 33MPH burning 17-18GPH. Full Throttle was 6100 RPM's and 46mph. I trimmed as much as possible and just couldn't get any faster.

Sounds great! Don't change a thing. No need to ever run a 265 over 40 mph.

 

[RobboNJ]

Your numbers sound about right. Dig around a bit more and you should be able to find a copy of the original performance chart for the 265 with 225's. Similar to attached.
It has taken me two seasons to figure out my MPG. I tracked my gas usage, miles and hours. At the end of it all it turns out my gauges are accurate and I get about 1.4MPG at 4200 RPM, pretty much what the chart says.
WOT, I don't do too much (well maybe a couple times a season after a big catch or a beer or two). Would rather baby the engines and keep them performing at dependable speeds. And, while the GW's can go fast, they are not speed boats.

 

[SkunkBoat]

I'm running Suzuki DF200s now. see first page of thread for details on performance.
https://www.greatgrady.com/threads/265-express-suzuki-df200apxw2.29099/

I had the original OX66 225s, 19M props. Sucked gas 1 mpg at 30mph on a good day. Over 30mph it really sucked gas. With the 225s it would reach mid 40s mph ....and $100 bills would fly out your ass.....

The boat doesn't handle speed over 40 well. If you have a need for speed its the wrong style of boat.

 

[Diad]

no, I likely wont hit full throttle again. I do just like to understand what the capabilities are. I am interested in cruising at 30 plus so I’m happy with the 265. I’m coming from a 31 Fountain which was a rocket with rod holders. if I ever decided to repower I’d probably look to go to 250’s though.

 

[Fowl Hooked]

I ran my '05 265 with 225s for the first four years that I had it, got hit with undetected exhaust corrosion that had reached the powerheads and opted for a total repower over replace the bad pieces and went with new 250s in 2015. Have been running the boat in both configurations on the Chesapeake, Potomac and Patuxent Rivers, and offshore for 12 years now. Props were the same on both engines, 15-1/4 x 19 SWS II 3-blade. Boat is bottom painted and unless heading offshore I typically run it in a similar fuel state as you describe.

With a fresh, clean bottom, good water and trimmed properly I've hit 50mph at 6000 rpms. Optimal cruise is typically more around 3800-3900 at 25-26 mph and 1.8 mpg. Normal cruise is more in the 4200-4500 range and 30-32mph. Really just whatever's comfortable given the conditions without running wide open. I do often push the throttles to the stops for at a couple minutes on my way back to the slip on the advice of my mechanic but its not a condition I ever run in for any length of time.

The typical 2-3 on the bay you describe can see a range of speed for me depending on the direction of the seas, periodicity of the waves, direction I want to go, how my knees and back are feeling that particular day, etc. If I'm able to run directly into the seas and trim and tab the boat up right (not to start this up again knowing Skunk's distaste for them, but I do use the tabs in some of these situations to get the sharp edge of the bow back down so it's not hitting on the bulky 'shoulders' of the hull), then 28-30 is doable but not comfortable for me. Lower 20s is more my average and for me at least, requires far less throttle management. Smacking hard into one of these short period 3 footers at 30mph is just not something I relish anymore. Rarely however do I find that I'm either directly into the seas or with them following, which is a different feel altogether. It's far more frequent that I find myself taking them on the quarter or even on the beam. Both require attention and I slow down again to just give myself more time to react and steer the boat through the waves. There's also a lot of days that it seems they're coming from multiple directions all at the same time and you're just steering for what looks like the best option.

2-3' is definitely in the realm of planing speeds for the 265, just how fast you want to run is a personal decision on comfort and punishment. I'm seriously considering 4-blade props with the goal of being able to plane at slower speeds and get up/back up on plane quicker. I find in those upper 2-3s or more that I'm constantly throttling up to get on plane after one of those rogue short period waves has knocked me down and as soon as she tips over and breaks free it feels like I'm immediately running 'on the edge of insanity' and so I'm throttling down to a more comfortable speed only to get hit and knocked off plane again. It's manageable today but I think the 4-blades will give me the lift to do it easier and as top end speed is not really a concern it seems like a fair trade to make.

 

[drbatts]

I ran a 265 with f225s for 9 seasons. Your numbers sound about right. My normal cruise was a typically in the 4600-4700rpm range. She would top out at 6300 rpm. but can't remember what speed that came with. Also don't be afraid to run it, sometimes a little more throttle will smooth out the ride.