74’ Seacraft 23 CC Rebuild

[Glosta23]

150HP ETEC G2’s

[kmoose]

Originally Posted by Glosta23

150HP ETEC G2’s

Roger that. What is the cost difference to a single 300 G2? I'm sure they will perform just fine but it will be interesting to see the cost and performance differences compared to the 300.

[Capt Terry]

Sorry I am responding at a disadvantage from only my cell phone while out of town. I would expect the combined CG of your 900 lb inboard and outdrive to be several inches to a foot forward of your transom. Bushwacker’s CG moved about a foot aft when he moved his ETEC 150 from his transom to a Hermco bracket. Therefore when you put two ETEC 150s on a bracket I would expect a bigger change than the 1.15’ you quoted. My 20” G1 ETEC 150 weighs 418 lb. The G2 must weigh more than that with power steering.
I agree with those recommending a large single instead of twins which I suppose opens up more space on the bracket for climbing onto when in the water.
The bracket floatation will not help your CG when underway.

[Glosta23]

Capt. Terry -

Checked my math again, and my distances from transom measurements and things seem accurate. Double checked ETEC weight as listed on Evinrude spec sheet and confirmed weight of my old engine and outdrive. Things look good.

Also received quote from Armstrong. Bracket weighs approx. 170 lbs and setback will be 30" not 36", so that should help me a little bit as well.

All interesting stuff to play around with in the hopes of getting the correct CG before actually bolting anything to the boat!! Fingers crossed...

[Capt Terry]

Looks like you probably did it correctly. I will examine it again next week when I am home. And you may tinker with the calc more as you have other items to consider to minimize the cg change. Best wishes.

[KNZ911]

Just saw that Michael Dru added 300 lbs in front anchor locker to even out balance of twin 150’s. For what it is worth.

[Capt Terry]

Glosta23-
Upon my return home I examined your cg calculation. Your use of my method and calculations appear correct. And recognizing in the CSC-world there are different opinions here are some comments:
1-Although your predicted 1.2’ cg shift aft may seem negligible, you may want to consider other ways to shift or reduce it. Bushwacker after his ETEC 150 was mounted on a Hermco bracket had to move his trailer axle 11.5” aft to maintain the original tongue weight. In addition it adversely increased his minimum plane speed from about 13 to 17-18 mph (don’t remember the exact numbers), He has plenty of posts describing the pros and cons of brackets.

2-KNZ911 mentioned it took 300# in the bow locker to balance out twin 150s. Plugging 300# and 21’ from transom in the calculation would put your cg right back where it was originally.

Best wishes and enjoy your project

[wattaway2]

Did you look into relocating the fuel tank forward shifting a lot of weight under the center console instead of behind it

[KNZ911]

Just to update a little. Michael Dru is looking to sell his twin 150's for a single 300. To much weight even with the added bow weight. I would love to have twins on mine, but it's just not the right sled for it.

[Glosta23]

KNZ -

Yes, Michael and I have messaged each other off the forum and he feels his boat will ride better with a single. Maybe I am just a contrarian but I'm still not convinced 100% and will reserve my judgement (on my boat) until I am absolutely certain which direction to go...

Each build is unique as you know and I think certain variables could potentially move the needle for me in either direction. I have friends who run both singles and twins and i hear a lot of conflicting information. Hopefully I'll make the right decision based on how I build the boat, and hopefully I won't regret the direction I choose... I do enjoy all the insight gathered from CSC though!! So much great info shared here...