69 20'cc Repower

[Lowcountry Native]

Thanks for the reply McG. If it where your boat tell me what you'd do.
Re-power with 115 2 or four stroke on cut transom?
Porta-bracket (they cost a fortune) ?
Leave the big bracket ?
The boat will not be left in the water overnight. I want to have a nice classic for my 3 boys.. Something for them to fight about when I'm gone lol. These are by far the coolest classics on the water.

Keeefus

[Bushwacker]

Welcome aboard Keefus! Amen to what Gillie says on power choices! The 20' SeaCraft hull is one of the most efficient and best riding deep-V hulls of it's size ever built, so it doesn't need as much power for equivalent performance as comparable boats. The 20' hull is relatively light and quite weight sensitive, so adding more weight to the transom will hurt the ride and increase min planing speed because of the aft CG shift that causes. Adding much more than about 115 HP only gives you speed that you won't be able to use in seas over about 3' because the boat will go airborne in those conditions at speeds over about 20 kts! Anything over about 150 hp is a waste of money IMHO, unless you only run in flat water and want to cruise at 35+ mph! Adding a bracket to a 20 just further amplifies the CG shift and it's effects, ESPECIALLY if you put a heavy 4-stroke motor on it. Speaking from personal experience, if adding a bracket, you will need to add trim tabs, a 4-blade prop and possibly a Doelfin or equivalent to get enough stern lift to match the ride and 12 mph planing speed I had with a 300 lb motor on the transom!

The only rational argument for a bracket on the 20 is the safety feature of a solid transom. If you're a diver and run offshore in big seas with heavy loads, which I do, then that is a significant benefit. I've concluded that the added safety and extra space are worth adding all that extra hardware, but minimizing engine weight is really important with a bracket. I ran a 300 lb 115 hp motor for over 30 years on my boat and would have probably bought a 115 E-Tec when I repowered, but they were not yet in production at the time. On the E-Tec I-Command gages, you can display the reading from the throttle position sensor in % of max. To give you a feel for how over-powered my Seafari is with the 150 (the E-Tec is actually 165 hp at the prop), even with a maximum load with 4 divers and tanks, I never use more than about 45% throttle to get on plane! Optimum cruise is about 35-37% at about 27-28 mph! If I ever get worried about running out of gas, I can just slow down to hull speed (~5 mph) at about 900 rpm and burn 0.5 gal/hr, thanks to the very lean stratified charge mode that the E-Tecs run below about 1400 rpm!

I would never even consider a bracket with no flotation like a Porta or Stainless Marine! If you want to boat to remain self bailing, you'll need one with maximum flotation, like a Hermco. Since the CC's are already a little more stern heavy than the Seafari, moving the gas tank, console and batteries as far forward as possible is also a good idea if adding a bracket. Denny