Seafari 25 performance

[cdavisdb]

A thousand words indeed. That pic helped a bunch.

My tabs are a couple of inches narrower and more inboard. Coming from very wide tabs, they don't seem to me to work all that well. I might switch to something closer to yours, but all in good time.

Denny,
I might have to raise the engine box to get 4 inch extensions in there. Food for thought.

I had already looked at the Moesley ballast patent and considered it neat but impractical. I'm rethinking that now after seeing the problem. If I could come up with a bullet proof fill and drain system that was fast, there is room on the keel forward of the seats. Will be doing some calculations on how much weight would be added.

Does anybody know how much room there is under the well between the seats at the aft end of the well?

Connor

[cdavisdb]

Just went out and measured, and I'm pretty sure I can get 4 inch riser extensions in without raising the engine box. that makes me very happy. Also got a chance to try straightening out the props. Boy, did I screw them up! Seems like I do something like this every time I buy a new boat.

Interesting info on props vs load. I will have to get a bunch of people on board and get some more data to see
how much relation there is with a duoprop.

Duoprops are different in unusual ways. Look at the props and they don't have all that much diameter, even though, with a total of 6 blades, there is a lot of blade surface to grip the water. What really grabs you is the pitch, its huge. They get away with this by turning them real slow. If you are towing behind the boat and look at the props, you can almost see them going around, compared to just a blurr with other drives. Very distinctive. The slow turning speed reduces cavitation and frictional losses, contributing to efficiency.

I've read several places that fuel injected engines were using very aggressive valve/cam timing/overlap (not exactly sure of the right terms). Bushwacker's comments about my vac results are consistent with that. It also makes the engine more susceptible to water intrusion via reverse reversion, a real nasty for me, with such a deep engine and since much of my diving is drifting with the divers, at idle where rr is worst, stern into the wind and wave. I like the idea of 4 inch extensions, very much.

Connor

[Blue_Heron]

I'm glad to finally see a dialog about a 25 Seafari. Thanks, Connor, for posting your performance numbers. I have some thoughts, but understand that these are mostly based on investigation and not actual experience, since the only time my 25 has been wet since I bought it was when I left it out in the rain.

I really hate the single stick control on the seafari tabs and will be changing to a two button soon.

If your tabs are Bennett, you might consider their auto trim system, the AC 3000. The rocker switch assembly runs $50 +, which makes the auto tabs that much more attractive. My 25 has Boat Leveler tabs which have a rocker switch almost identical to the Bennett, so I'm assuming the AC3000 will work on them as well.

Has anybody tried putting extra weight, lead, concrete, whatever, way up in the bow of this boat? ...Maybe a couple of hundred lbs in the bow would help keep the stern from sinking so far. Might also damp the roll a little.

I understand it is very common to find ballast placed low and forward in these boats. Mine didn't have any, but I plan to place a fresh water tank under the cabin/cockpit sole forward of the fuel tanks to serve as both adjustable ballast, and fresh water for wash down.

Does anybody know how much room there is under the well between the seats at the aft end of the well?

The fuel tank compartment ends where the deck drops 6" to the cockpit sole which continues into the cabin. There is a plywood bulkhead under the deck at the transition. The bulkhead in my boat has a cutout that allows access to the space under the cockpit/cabin sole. This space has a sole that sits atop the stringers and tapers in width, and to a lesser extent height, toward the bow. I don't have exact measurements, but I believe I will be able to fit a 38"L x 20"W x 9"H, 25 gallon tank under there which will weigh a little over 200lbs. full. I plan to build a plywood mockup of the tank to test the fit before I order it.

Seafari25, the tandem trim tab setup is very cool and an ideal solution for these variable deadrise hulls. What was used as a linkage between the inner and outer tabs?

Dave

[cdavisdb]

A pic may be worth a thousand words, but you have to actually look at the pic. I totally missed the double tab. That is amazing. Ditto on Blue Herons question. Maybe I can do the same on mine.

Dave, thanks for the measurements. I also was thinking water storage before I thought about Bushwackers comment.
If you would like to get together and compare boat notes, let me know.
Connor

[Blue_Heron]

If you would like to get together and compare boat notes, let me know.
Connor

Connor,
You're in Sarasota, right? I'll be going down to Bonita Springs on Wednesday 11/11 and returning Sunday 11/15. I'd love to stop by and see your 25 on the way down or back if that's convenient for you. I've never owned an I/O before and I'd like to get the benefit of your experience.
Dave

[seafari25]

A pic may be worth a thousand words, but you have to actually look at the pic. I totally missed the double tab. That is amazing.

That's funny stuff Connor!

The "plates", as I like to call them, are all one piece 3/16 steel, bent the shape of the hull and welded to make a channel in the middle(can be seen right side of port tab, left side of starboard in above pic). The top of the channel is level with the top of the plate. The bottom of channel is level with bottom of plate but the forward edge is bent(curved) upward so it never drops below hull and also seals the channel from the front. The rearward edge of the top of the channel is cut out to allow better access to bolt it to the trim tab. The plates are each secured with 4 1/4" SS bolts.

Wow that's hard to explain. That's why I hoped a picture was worth a thousand words.. JK...Happy to answer any further questions fellows.

Brandon

[cdavisdb]

Dave,Come on down!

Either day will work, 11/11 or 11/15. I can definitely be home on the 15th. The 11th is a work day, but its my company, so there is some flexibility. Let me know your schedule and I can almost certainly find a way to make it work, The 13-14 is out.

I live close to US41, about 8 miles from the nearest interstate exit.

Connor

[cdavisdb]

Ok, Brandon, I'm dense. Could you possibly take some closeup pics of those tabs. I promise to look closely at them.

Couple of questions. Do the steel tabs move up and down with the bennet piston? Are they attached to the hull at all or only attached to the bennet tab? If so, they look fairly far off center to the piston. Has that ever caused a problem?

Connor

[seafari25]

Connor

Yes the steel tabs move with the piston and only attached to the bennett tab, no contact with the hull. The steel is sistered to the aluminum each with 4 bolts.

As far as I know, Gramps had the plates made while he was chartering the boat in the mid to late 70's on Lake Ontario. He replaced the original joy stick in the 80's with the double rocker still on now and I had the original actuators replaced a few years ago. Other than being upset that they cut holes in my inner transom when installing the actuators , no problems. Structurally, the steel has held up quite well. I removed the plates about 8 or so years ago and sandblasted them. I had to weld in a small patch on one that I blasted through and I coal tarred them. They'll last a few years yet but I think I might try making them out of aluminum next time.

I'm hoping the boat is out of the water by now and I'm planning to hit the cottage this weekend to pull the docks. My good camera crapped out but I'll try to get some close ups with the blackberry and get them up before she goes to hibernate for the winter.

Brandon

[Gary Hill]

When I repowered a couple years back, I had the four inch extensions on my engine. I looked at several boats and they all had them (of couse mine is a inboard).