18 Outrage Re-power with 250-HP

Optimizing the performance of Boston Whaler boats
biggiefl
Posts: 276
Joined: Thu Jul 11, 2019 1:31 pm
Location: south Tampa Bay area
Contact:

18 Outrage Re-power with 250-HP

Postby biggiefl » Fri Jul 12, 2019 11:24 am

I am in the negotiation process on a 1986 Outrage that has a very nice Yamaha F115. My long time dream has been to put a 300-HP engine on an Outrage, but I think that might be too much--even though most of us has seen the Montauk video with a 300-HPDI on it.

In Florida slightly used 250-HP engines are very abundant as many buy a boat with 250-HP engines due to price, and a couple years later upgrade to 300 or 350-HP engines.

I know some have overpowered their 18 OUTRAGE boats with twin 90-HP and twin 115-HP engine. Can you share some performance with me?

Anyone else running more than 150-HP have some numbers as well?

My goal is 60-MPH so I can cruise at 35-MPH around 3,500-RPM engine speed or less.

I know a 150-HP will do roughly 50-MPH if setup correctly. If I can get close to my goal with a 200-HP or so I'm game.

Also how does [an OUTRAGE 18 with 200-HP or more] handle at speed?

I know an Outrage 18 at 60=MPH will be a short, insane ride.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall. :roll:

biggiefl
Posts: 276
Joined: Thu Jul 11, 2019 1:31 pm
Location: south Tampa Bay area
Contact:

Re: 18 Outrage repower w/250hp

Postby biggiefl » Thu Jul 18, 2019 1:02 pm

Picked up my OUTRAGE 18 today. The F115 engine is mounted all the way up and has a stainless steel 17 or 18-pitch propeller. The engine hit 5,800-RPM. Honestly, the F115 is not a bad match for the 18 OUTRAGE. No GPS but seat of my pants says low 40-MPH boat speed.

In speaking with others, I am leaning towards a 200 to 225-HP engine, as I think even a 250-HP might be excessive. The marina that I bought the OUTRAGE from has a Mercury 225 (a Yamaha) with more than 300- hours on it and would do an even swap for my 115 as the marina needs one for a pontoon boat. I think the boat speed will be high 50-MPH range, which is close enough even though they say the first generation Mercury-Yamaha 225 engines are more like 210-HP.

Right now the Yamaha F115 is roughly 400-lbs. I have twin batteries in the rear splashwell so 120-lbs more there. The hull sits OK. I think with the batteryies under console and a 580-lbs engine, I'll be fine.

Buckda ran twin 90 E-TEC (on jackplates) so was probably pushing 650 to 700-lbs.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall. :roll:

User avatar
Phil T
Posts: 1090
Joined: Thu Oct 22, 2015 6:08 pm
Location: Was Maine, now Kentucky
Contact:

Re: 18 Outrage Re-power with 250-HP

Postby Phil T » Thu Jul 18, 2019 2:23 pm

Nick--How about throwing some bags of sand in the splashwell to simulate the new weight and see how she comes off plane and backs down into waves.
Member since 2003
1992 Outrage 17, 1992 Evinrude 115

jimh
Posts: 6905
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: 18 Outrage repower w/250hp

Postby jimh » Thu Jul 18, 2019 4:46 pm

biggiefl wrote:Buckda ran twin 90 E-TEC (on jack plates) so was probably pushing 650 to 700-lbs.


Yeah, but Dave only weighs 145-lbs. You gotta figure that into the weight equation. :-)

And there were set back brackets. You can see more details of his rig at

http://continuouswave.com/whaler/cetace ... age81.html

GAMBLER did seem to handle everything thrown at it. We spent may weeks cruising with Dave. You can see a lot of GAMBER in this SAIL LOG:

http://continuouswave.com/sail-logs/gb2009/

My favorite shot:

Image

As usual, those seas on Georgian Bay were bigger than they look in the picture. Look at the flags: out straight, so wind was 25-knots, and the fetch was about 80-miles.

I don't recall the top speed for GAMBLER. Dave could always outrun my boat, which peaked at about 43-MPH. So I am sure 50-MPH was in reach for him.

Here's a short video:

http://continuouswave.com/whaler/movies/twinETEC90.mov

Watch that short recording to get a feel for the boat’s trim and handling underway.

As you can see in the many pictures and in the motion picture short recording, the OUTRAGE 18 hull did not show any signs of suffering from all that engine weight. In c.1985 many OUTRAGE 18 boats were rigged with twin 70-HP two-stroke-power-cycle outboards, and that weight was never a problem. Now the 250-HP—that is going to be a problem, well, at wide-open throttle it will be.

biggiefl
Posts: 276
Joined: Thu Jul 11, 2019 1:31 pm
Location: south Tampa Bay area
Contact:

Re: 18 Outrage Re-power with 250-HP

Postby biggiefl » Fri Jul 19, 2019 10:24 am

Phil I have roughly 520-540lbs in the stern now, another 50 or so won't make a difference. My 200lbs will offset it unlike Dave ;) Plus moving battery under console will offset some. Twin 70's back in the 80's was roughly 520lbs plus one battery and they are at my expected 580lbs.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall. :roll: