1977 18sf vs 2003 20sc

[Bushwacker]

Originally Posted by dginge

Ok...I'll be more broad. how Does the 20 ride overall with a 4stroke 150?

Those motors are at least another 50-60 lbs heavier than my E-TEC (be sure to compare WET weights, with full filter & 6-8 qts of oil in the crankcase!). If it's hanging on the transom with a 3B prop and no fin, I'd guess it would perform about like mine did originally before I added that stuff, i.e. min planing speed in the low-mid 20's. If motor is on a bracket and they didn't move the console/batteries/gas tank forward to rebalance (an option I didn't have in the Seafari), I suspect it'd be worse.

One clue as to how well it's balanced is how deep the chines are immersed at the transom at rest. First 2 pics below show how mine sat with 300 lb motor with full and empty gas tank. With an empty tank, transom chine was maybe 1" deep, with trim tabs almost at surface, and maybe 2" deep with a full tank (Pic 1 & 3) . In last pic with bracket and new motor, chine is 4.5-5" deep. (35 gallons). The 2" bootstripe is in same location in all pics, just repainted w/new motor. Remember that the Hermco bracket has a lot more flotation than the typical Armstrong bracket, so it probably offsets most of the motor weight. I suspect waterline would be similar if motor was hanging on transom. The big CG shift doesn't show up till you get on plane and flotation tank is out of the water!