Finally,I'm in the water - some results

thedink9 · #1 05-27-2005, 10:21 PM

Well after 18 months of work and lots of help from many of you, I'm in the water. [img]/images/graemlins/grin.gif[/img]
I'll get around to posting the work related pictures as soon as I can figure out to to post a picture, but here are some performance results I noted today.
With 100 gal of fuel and three people onboard I was cruising at 4000 RPM and doing 25.5 kts.This was in a 2-3ft. head sea. Not bad and I'm very satisfied. At WOT I was doing 37 KTS at 5200RPM. Oh yeah I have a Yamaha 250 EFI mounted on the transom and it's spinning at 15 1/2 x 17 Stainless prop. I was burning 12-13 gal/hr at cruise.
And the fluke fishing wasn't bad either as my son and I caught 12 and kept 6 between 3 and 5 lbs. [img]/images/graemlins/smile.gif[/img]
Any comments on the performance? Dink

ScottM · #2 05-28-2005, 09:35 AM

Rich,
Congrats on finally splashing the boat. It must be an awesome feeling. Your performance #s sound just about right based on load and conditions. 5200rpm sounds a little low for WOT. Turning around 5500-5600 would be better for longevity. Try running her with a light load and the engine trimmed up to see what you get.

Email me the pix if you want and I can post them for you. Can't wait to see the boat in August at the BBQ.

abl1111 · #3 05-28-2005, 01:35 PM

I finally have to ask - what does WOT mean ?

peterb · #4 05-28-2005, 02:55 PM

Wide Open throttle

thedink9 · #5 05-30-2005, 10:16 PM

Scott

I thought the 5200 sounded low to me as well. Once I burn off a bit of fuel, I try to open it up again and see what I;m turning, I haven't done a tune up either so I'll be getting to that soon, as well. I do think the prop is the correct size though. Dink

Fr. Frank · #6 05-31-2005, 07:59 AM

As a former Yamaha and Merc service manager, I need to say that you should be turning the recommended RPM range at MAX LOAD. You shouldn't have to "burn off" or unload to reach the 5500 rpm mark. You should be propped to reach that RPM with full fuel and at maximum gross weight properly trimmed.
My 20' Seafari with 150 Merc turns 5550/5600 RPMs at max load and full fuel. With a 1/4 tank and just me, I can turn nearly 6000-6100 RPMs at 40+ knots. Unless your engine has a high RPM harmonics problem like the old inline 6 Mercs, you're MUCH better off 300-500 RPMs high than low.
Besides, most of us don't run WOT very much. Shouldn't have to. The fish aren't that fast.
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