Call me crazy

[Capt Terry]

Locke n Load

It is good you are sharing some of your ideas for responses. CSC members have differing opinions based on their experience and boat usage. There is some excellent advice if you search for it. For various reasons there are modification projects that never get completed. Less time and money will be spent by not prematurely launching into screwy projects. And as I have heard from Carla Moesly (paraphrased), repair or modify or boat to serve your needs, but not to flip it, because you’ll never get out of it what you put in it!

As SSPBill remarked, check out Bushwacker’s posts on brackets, engine weight, etc. Bushwacker is the former CSC performance moderator who converted his 20’ Seafari to a full transom and bracket, but continued to use his ETEC 150. He liked the full transom and the platform, but his CG moved about 11” aft and found he needed to run faster to maintain a minimum plane even with trim tabs. I posted “Estimating CG Shift with Heavy Engines” which shows how to estimate the CG shift for moving the engine to a bracket or for relocating other heavy items. Based on these calculations you’ll understand where to temporarily locate weight to predict the effects of your anticipated changes.

WEIGHT- The narrow Seacrafts were designed when outboards engines were in the 300# range. My ETEC 150 HO is 418#. But the engines you mentioned are too heavy, the Verado 400 is 668# and the Suzuki 350 is 727#. Bet your '71 scuppers will no longer be self bailing.

HORSEPOWER- The HP of the aforementioned Suzuki and Verado are way more than needed for a Seafari. At WOT I can hit 41-42 mph on lake conditions with either a properly propped High Five or Inertia. I originally hit 50 mph with the ETEC; but not only was the original prop overpitched thereby not achieving recommended RPM, but it felt too fast for good boat handling. Search out comments on chine walking which occurs at high speeds. There may be some guys with 200s, but would think 175 is a recommended max.

Keep researching and thinking. Kind of like the old saying, “Measure twice and cut once” or my Dad’s tongue in cheek version, “Darn it, I’ve cut it twice and it’s still too short!”