25 seafari

[ScottM]

Let me first qualify my comment by saying I have ZERO experience with a 25' Seafari, but with everything I've read here since the site began in 2002, it appears some members know A) a lot about CG and boat design, and B) know a lot about this particular model. Now here goes my 2 cents...stick with an I/O config in this boat seeing as that is how it was designed. There weren't any OB versions ever made from the factory, so you're in for a lot of unknowns with switching to a bracketed OB. We can all argue the pluses and minuses of both OBs and I/Os, but it appears to me this boat was meant for an I/O (either single or twin) and should be left that way. Stepping off my soapbox now...

[cdavisdb]

IMHO, CG, both vertical and horizontal, is pretty important in these boats. Bigfluke noted that the CG (I assume with the orginal twins) was farther aft than usual. He got his best performance moving the CG forward and adding weight. My boat is lighter than original by about 500 lbs due to going to a single I/0 and not tail heavy at all. Changing power plants moves the CG forward, but mine still likes more weight forward, especially when running light. When coming home from a long trip, light on fuel, water, ice and groceries moves the CG aft, one big guy moving from the engine box to the steering area makes a big difference in pitching and seems to increase speed.

Vertical CG greatly affects rolling. My experience with deep Vs is that those with very low CGs are reasonably docile lying in the trough. High CG deep Vs can roll your guts out. The seafari 25 is not as bad as some, formula 23 for example, worse than others. I've been very careful not to add weight up high. Also, when light, my boat easily rolls the outboard hull panel out of the water at the stern, accentuating the roll. That is not as bad with more weight in the boat. I'm planning to do some stuff with bigger trim tabs to try and damp down the roll.

I'm thinking along the same lines as ScottM.

A bit rambling, hope this helps.

[cdavisdb]

Just a guess on the 140s, 280 horse power with two drives will be significantly slower than my single, but faster than a 25 Bertram with twin 130s( a much bigger, heavier boat). 18 knots most efficient cruise on the Bertram, 23-25 knots on my Seafari, guesstimate on the 140s in a Seafari 25: 23 knots medium load, 21 knots heavy, lots and lots of wonderful torque. Prop selection will be critical.

[eggsuckindog]

I honestly think that trying to work with the old motors is a mistake - it seems you are always chasing some new issue and the parts eat you up =twin drives as mentioned are a big negative as well. You have to understand the limits of the power available back then, I would bet if he had todays outboards they would have come with that option, the V6 175 Merc did not come out until 1976.

Wouldn't a bracket help somewhat with roll -
kinda like a trim tab ?? as we all do on our boats a good deal of weight could be moved forward - like batteries.






Also seems cutting weight in half would have to make the boat less tail heavy - I'm kind like Don though as I have never been accused of being a rocket scientist, many other things but that wasn't one of them.

[Blue_Heron]

Originally Posted by ScottM

...stick with an I/O config in this boat seeing as that is how it was designed. There weren't any OB versions ever made from the factory, so you're in for a lot of unknowns with switching to a bracketed OB. ...this boat was meant for an I/O (either single or twin) and should be left that way.

George,
I have to agree with Scott. His post pretty much mirrors my thoughts when I made the decision to stay with the I/O.

I also agree with ESD on the engines. If you're going offshore, and that's what this boat was made to do, you don't want unreliable power. If you can go through the engines and outdrives, and you're sure they're reliable, go for it.

I know there are some 25s out there that have been modified for outboards. I've seen them for sale with brackets, and one with a transom mounted outboard. But I don't know of any members here running a 25 Seafari with outboards, so it may be difficult to get real world feedback on that option.
Dave

[shana]

one thing about the 4 cyl motors is there is a lot of them around had many boats in the past with them only as singles never twins one was on a johnson boat and it was a heavy boat a little slow out of the hole but was ok thanks your all a big help

[eggsuckindog]

The boat was marginal with inline 6's, if your going to be doing much work and/or spending money I would do something else

[strick]

An e-mail that was forwarded to me by Bigshrimpin several years ago regarding the 25 Seafari power options as told by Mr. Potter:


Hi Tim,
Please tell Strick he has the best riding SeaCraft we ever built. It is not a boat for someone who doesn't know how or doesn't want to use trim tabs and the power trim of the IOs or outboards to get the most out of the hull design. The boat has the deepest V (25degrees) of any SeaCraft and, due to having no lifting strakes, it is more sensitive to "leaning" in cross winds and from weight shifts while on plane than other SeaCrafts and other deep Vs. BUT, it is like flying an aerobatic plane, if you know how to use the trim you can set that boat up to run through anything you have the nerve to be out in with remarkable comfort and safety. AND, because of the Variable Deadrise Hull design it is a very stable platform at rest or at trolling speeds. I wish we had a recording of the story a guy told us about his run from St Croix to St Thomas during a major hurricane flying through and off 25 ft and larger seas in the dark! Pigs don't fly!
Best regards,
Bill Potter
ps A SeaMark twin Fiberglass Bracket and properly positioned and operating trim tabs would be my recommendation unless he is going to go with a big single diesel duoprop stern drive or smaller twin duoprop sterndrives. ( Duoprops minimize torque roll)

strick

[shana]

strick thanks for the reply very well worded will take what you send and think hard on it money tight and dont want to do it the wrong way thanks george