23' CC with Suzuki DF175

[wattaway2]

In your calc’s don’t forget to include ice for the cooler you and your crew and miss. Stuff ect

[SeaPlusPlus]

Originally Posted by wattaway2

In your calc’s don’t forget to include ice for the cooler you and your crew and miss. Stuff ect

Yeah thanks for the reminder! I did factor all that in though to get the estimated 5226.4 fully loaded weight.

Originally Posted by SeaPlusPlus

Take that full restored weight and add 500lbs of persons, 100lbs of gear, 100lbs of boat jewelry, and 50 lbs of ice to give a fully loaded weight of 5226.4lbs.

[FLexpat]

I am thinking you would be fine and you have nothing to lose besides the time for a swap. My 23 Sceptre originally came with a 233 Mercruiser I/O. I seriously doubt that clunky 351 2bbl ever got much above 215 at the crankshaft, no way did it get very much at the prop. It weighed about 600 lbs more than the Zuke and the pre-Alpha drive was mounted WAY deep. We played with props a bit but probably not enough and prop tech was not too advanced then. Still got ~35-40mph WOT and comfortably cruised about 25-28. If it gets snotty you won't be going fast so you won't need much HP to run about 15mph and you could probably stay on plane at 12-14 with the light OB.

My calcs say that it takes a bit over 110HP at the prop to get a light/normally loaded 23 on plane (maybe less w an OB) and probably just a bit more for a comfortable cruise.

I would run Crouch's with a constant of about 230-240 with that setup though.

[77SceptreOB]

Although I'm not a fan of underpowered boats and have commented so on other similar threads, I do believe your scenario will work satisfactory for your stated expectations.

From a historical perspective we have run our 1977 23' Sceptre with a 200hp Johnson from 1976-1979 and an Evinrude 200 from 1980-1988. In both cases the boat performed fine in offshore and inshore use. It never seemed sluggish even when loaded pretty heavy. I also don't think either one of those engines were actually over 200 hp at the prop and probably significantly less during that era.

A few years ago, I had a plugged carb on my Yamaha 225 and was effectively running on 5 cylinders thus netting out approximately 185hp. During this time the boat still performed fine. In fact I didn't even know I was a cylinder down because the boat would run 37 mph at 5100 rpms and still had a decent hole shot with a 17 pitch prop. I ran it this way for approx 50 hours before the carb issue was discovered during a "tune up". After the carbs were rebuilt and synchronized the boat ran 43 mph at 5800 rpm. That was much improved, but proved at 185 HP even over propped the boat ran pretty good.