performance of twin 150's on 23

[cutthechop]

can anyone give me performance specs on twin 150 2 stroke yamaha's on the 23 cc with bracket? most importantly can it plane out with single 150? plan on using for ne offshore fishing and need planing capability if one goes down. thanks

[Capt Chuck]

My cousin's 24' Silverhawk (Same as SeaCraft Hull)had twin 150hp Yammies on a Armstrong bracket. He could not plane the hull with just one of the motors..

[JohnB]

I have been on them with twin 150's and they WILL NOT plane.
Probably 200's is the min, maybe 225's, depending on weight/load. I know they will plane with 250's.

[Fr. Frank]

Back in late '84, the Palm Beach Police Dept had a 23 SF with twin Evinrude 150's, transom mounted, and the only way it would plane with one engine was with the tabs full down, and the non-functioning motor full up and in calm water. Even with all that, it really struggled to get on plane, but did so eventually. With both engines it topped out at about 44-45 mph.

After toasting two powerheads in two months, they repowered the boat with twin EverRude 235's which, like the 150's, were provided for them free by OMC's testing facility in Stuart/Jensen Bch. Planing on one engine then became easy, and top speed was raised to 58-60 mph. The boat was serviced at Rybovich/Spencer Marina and Boatyard where I worked for a time.

[Trey1096]

I’ve got twin Black Max 200’s on the transom spinning 21” props and it struggles to plane on one if the water isn’t pretty flat. Full tabs and full tilt on the other engine really helps

My engines are a little long in the tooth and my props might be a little flat so with a pair of 200 Opti’s or EFI’s it would probably be a little easier. You better have a bracket with some flotation. My engines are pretty light, a little shy of 400#, and it’s too much weight.

Seems like someone would invent a spare prop that was ‘reversible’ so that it could be used on a std or turned around and put on a counter. A prop that didn’t have any skew, cup, or rake, and had a pitch steep enough to let you plane on either the std or the counter long enough to get you home.

Trey

[peterb]

My old SeaCraft had twin 150 Yamahas and I have twin 200's on the current rig (with a full flotation bracket).

You cannot plane on just one engine (on either of the above setups).

Here are some performance numbers

Twin 150 SWS carb engines:
WOT - mid 40's
mileage - 1.6 mpg or so at cruise
Min planing speed - 16 to 17 miles per hour

Twin 200 OX66's:
WOT - high 50's
mileage - 1.7 mpg or so at cruise
Min planing speed - 21 miles per hour

[Briguy]

I CAN plane my boat with one of my "litte" 115's. Top speed is about 14kts at 4400 rpm with one motor almost out of the water and tab's down. I would not feel comfortable using this set up for any extended period.

[Fr. Frank]

I'd love to see the torque curve for the 115 that will plane a 23 from offset to one side. As for planing from the middle. I've rigged more than one 23 CC with a single 140 Evinrude back in the early 80's. As I recall, we had them propped with 15" pitch props, and they had a top end of about 25 or 26 mph.

I think you could probably get a single 140/150 to plane the hull if you had the right prop to switch out when needed.

[Briguy]

I must have very strong motors. With 60 gallons of fuel on board I can hit 40.5kts., yes kts. I will demo this boat planing on one motor at Longpoint. I will also invite 10 fellow seacrafters to join me on the boat at longpoint so you can see how well she rides with a big load. I run 24" stainless props and she can hit 5950+rpm's at wot.
Longpoint is now only 40 days away.

[peterb]

Brian,

Do you mean KNOTS or Kilometers per hour?

You probably do get an extra couple of miles per hour by not having a big fiberlass t-top.

Peter