Seafari 25 Conversion Thoughts on Power?

GameOnSalmon · #1 05-19-2014, 12:42 PM

Hey Guys...

Put my 25' seafari up and could not get what I wanted out of it. Started the Tear Down Conversion yesterday... Removed Both engines, outdrives and housings... Glass Work 2morrow...

Now... My Question...

The seafari is only 400 lbs heavier than the 23' Tsunami according to brochure.... I Am considering running the following set up and am looking for some thoughts and or opinions...

Will be running a Porta Bracket and am Wondering if I am better off running one 250 Etec.. will be a used motor or better off running Twins...

Twins would be either 150 or 200 Johnson Ocean Runners the 200's might be overkill I saw where Bilgerat stated almost 50mph with twin 150 mercs on his...

Pros and Cons or thoughts... to the Power? I am ready to order the Porta Bracket as soon as I make a decision.... Just concerned that a 250 or 225 will Just not have enough poop to run it out... but hate the idea of double the costs with Twins... What you'all think..?

Thanks In advance for Replies...
Robert

nestorpr · #2 05-19-2014, 12:48 PM

I think the 250 should be enough for a decent top speed and fuel economy, especially with the efficiency of this hull. I know a guy with a 25 Bertram flybridge (a heavier, less efficient hull) with 1 300 etec and he reports a top speed of almost 40 mph with a cruising speed around 30, that's great for most places. If you want more top speed then how about a 300 etec unless you already have a used 250 lined up?

kmoose · #3 05-19-2014, 03:43 PM

I know you could get a great deal on used 30 inch 300 Suzuki and be totally hooked up. The fly by wire would make it a breeze to set up. A 250 would work but that hull is worth not under powering.

cdavisdb · #4 05-19-2014, 05:03 PM

The 25 will balance much better with 1 engine, important in that hull. I don't think it will be very fast with the 250, depends on what you need. I run mine with a 5.7 v8 I/O duoprop that is around 290 hp. Most efficient cruise is around 25-26 knots with a moderate to light load, but it drops fast when you load the boat down. With another 1000 lbs loaded for a Bahamas trip, 21-22 knots is most efficient cruise(7-8 inch vacuum and I don't want to run any harder)
.

Torque will be a significant issue. 2 stroke outboards often don't have near as much torque as I/Os of the same horsepower. It makes a huge difference if its real sloppy and you want to slow way down. A very deep hull like this one takes a lot of torque to stay on plane when going slow.

Just my opinion, but I'd stay with a single I/O in that hull, much better balance and CG, plus no torque issues.

During your rehab, check the stringers carefully underneath the bunks. Consider adding a bulkhead forward.

Connor

Bushwacker · #5 05-19-2014, 05:19 PM

Congratulations on deciding to keep that boat! It's a rare and very special model that few people understand or fully appreciate it's capabilities! Forum member Big Fluke is a naval architect in Hawaii that has a Seafari 25 and says once you get CG location right, it's one of the most seaworthy small boat hulls he's ever tested!

Carl Moesly designed the Seafari 25 to have a ballast tank up forward, similar to what he used in his race boats. http://www.moeslyseacraft.com/25-seafari.html However he sold the company to Potter before ever building a 25, and Potter apparently never understood the ballast tank so left it out. Potter has been quoted as saying that the 25 Seafari is the one boat he could never get to "handle right"! Connor Davis is the resident authority on this hull, with lots of experience running his boat in some big seas on several Bahamas trips; he says it runs and handles much better with weight up front.

Although I have a lot of experience with a bracket, having adding one to my boat after running it for 31 years with an OB on transom, I believe going to a bracketed outboard on the 25, ESPECIALLY one with no flotation, is a big mistake. The last thing that boat needs is a rearward shift in CG; if anything it needs to shift forward, so I'd consider installing a big fresh water tank up front. Dave (Blue Heron) and Strick, who bought their 25's with blown engines, decided to stay with an I/O to avoid shifting the CG and I suspect Connor would recommend the same. Although a big outboard, especially an E-TEC, will weigh much less than an I/O, most of the I/O's weight is forward of the transom, so an outboard on a bracket will shift the CG aft in the wrong direction. Carl told me that the CG on the 140 I/O Seafari 20 is further forward than it is on the OB model. Forum member Tiny who once owned both an I/O and OB Seafari 20 said that the I/O model does indeed plane easier at lower speed than the OB model and he felt that it rode a bit softer. I'm sure a comparison between an I/O and OB Seafari 25 would be similar.

I would suggest that a single I/O with a duoprop type outdrive, with a modern EFI V-8 like Blue Heron and Island Trader bought, would be the optimum configuration for that boat, and it would be lighter and thus perform better than the twin I/O's than it originally had.

GameOnSalmon · #6 05-19-2014, 06:39 PM

Quote:

Originally Posted by cdavisdb

The 25 will balance much better with 1 engine, important in that hull. I don't think it will be very fast with the 250, depends on what you need. I run mine with a 5.7 v8 I/O duoprop that is around 290 hp. Most efficient cruise is around 25-26 knots with a moderate to light load, but it drops fast when you load the boat down. With another 1000 lbs loaded for a Bahamas trip, 21-22 knots is most efficient cruise(7-8 inch vacuum and I don't want to run any harder)
.

Torque will be a significant issue. 2 stroke outboards often don't have near as much torque as I/Os of the same horsepower. It makes a huge difference if its real sloppy and you want to slow way down. A very deep hull like this one takes a lot of torque to stay on plane when going slow.

Just my opinion, but I'd stay with a single I/O in that hull, much better balance and CG, plus no torque issues.

During your rehab, check the stringers carefully underneath the bunks. Consider adding a bulkhead forward.

Connor

Connor, I really appreciate you taking the time to reply in detail. I cannot wrap my brain around the I/O i not only hate them, I despise them, Especially after the mess I took out of 25 Beast Yesterday. The only Outboard Model I know of is the one with Twin 150 Mercs on it... I am really leaning towards a Single 250 Right now as thats what the budget will allow and then looking for a 300 Next year after I have ran this boat some.

as Bushwhacker said I know you are the resident expert on these 25 seafari's, Is the Difference so Much bigger between this and a 23' Tsunami that a 250 wouldn't cut it? Looked a bunch of boat specs on the evinrude website with real #'s on the 225 and 250 engines.

Right now I am Really leaning towards the 250 mercury EFI used of course and then doing the upgrade when i can... Total weight will be close to 700lbs vs the 1200 lbs i just took out. By using the Porta Bracket I am only using 17" of setback instead of the 30 traditionally used...

Any other thoughts...?

Thanks Robert

Quote:

Originally Posted by Bushwacker

Congratulations on deciding to keep that boat! It's a rare and very special model that few people understand or fully appreciate it's capabilities! Forum member Big Fluke is a naval architect in Hawaii that has a Seafari 25 and says once you get CG location right, it's one of the most seaworthy small boat hulls he's ever tested!

Carl Moesly designed the Seafari 25 to have a ballast tank up forward, similar to what he used in his race boats. http://www.moeslyseacraft.com/25-seafari.html However he sold the company to Potter before ever building a 25, and Potter apparently never understood the ballast tank so left it out. Potter has been quoted as saying that the 25 Seafari is the one boat he could never get to "handle right"! Connor Davis is the resident authority on this hull, with lots of experience running his boat in some big seas on several Bahamas trips; he says it runs and handles much better with weight up front.

Although I have a lot of experience with a bracket, having adding one to my boat after running it for 31 years with an OB on transom, I believe going to a bracketed outboard on the 25, ESPECIALLY one with no flotation, is a big mistake. The last thing that boat needs is a rearward shift in CG; if anything it needs to shift forward, so I'd consider installing a big fresh water tank up front. Dave (Blue Heron) and Strick, who bought their 25's with blown engines, decided to stay with an I/O to avoid shifting the CG and I suspect Connor would recommend the same. Although a big outboard, especially an E-TEC, will weigh much less than an I/O, most of the I/O's weight is forward of the transom, so an outboard on a bracket will shift the CG aft in the wrong direction. Carl told me that the CG on the 140 I/O Seafari 20 is further forward than it is on the OB model. Forum member Tiny who once owned both an I/O and OB Seafari 20 said that the I/O model does indeed plane easier at lower speed than the OB model and he felt that it rode a bit softer. I'm sure a comparison between an I/O and OB Seafari 25 would be similar.

I would suggest that a single I/O with a duoprop type outdrive, with a modern EFI V-8 like Blue Heron and Island Trader bought, would be the optimum configuration for that boat, and it would be lighter and thus perform better than the twin I/O's than it originally had.

Bushwacker... Thanks for the Lengthy reply and I appreciate it. Was not an easy choice to keep this bugger around... but at the end of the day everyone was lowballing and the condition of this hull is just too good.

As I told Connor, I despise I/O and guess I am gonna end up the 250/300 outboard guinea pig over the next year...

Expecting to have the Glass work done by Thursday and ready for a Bracket and Motor...

I guess the worst case scenario if it really ends up being a total Turd Bucket I can always Repower it with a I/O and sell it...

Thanks Robert

GameOnSalmon · #7 05-19-2014, 06:42 PM

Quote:

Originally Posted by kmoose

I know you could get a great deal on used 30 inch 300 Suzuki and be totally hooked up. The fly by wire would make it a breeze to set up. A 250 would work but that hull is worth not under powering.

Moose... It would have to be a Hell of Deal, I love the Suzuki engines but am guessing that one is outta my range. At the end of the day I keep leaning back to the Etec Outboards... Can't do one now... Prolly gonna be a 250 Merc EFI and then Try to pull of an upgrade next year... Now if that deal is Super Screaming... Please PM me.. Would Love more details..

Thanks Robert

cdavisdb · #8 05-19-2014, 08:47 PM

If you are dead set against an I/O, a single outboard on a short bracket should work. You may find that the 250 is too slow in a calm water cruise mode for your desire. However, the hull runs so much faster than most hulls when it is bumpy, that the average is a lot closer than it appears at first. I went from a 24 Seabird deep V to the 25, lost 2-3 knots calm water cruise when loaded heavy, but, on long open water runs I still get there sooner with the 25. Much sooner if it is bumpy. I just don't need to slow down in any conditions I'd have been willing to take the Seabird out in. If it really gets nasty and you need to slow down below 18 knots, I think you will not like that 250, because it will probably want to jump on and off a plane.

Balance will be tricky and will take some experimentation. You can allow for moving the CG aft by adding weight, water or fuel or pig iron, under the berths. The boat really does like weight forward. Tabs help, but just are not the same thing Vertical CG might get you. Because the boat is very very sharp, it rolls. The VDH hull keeps it from snap rolling,the bane of many deepVs, but only as it was originally built. The hull is very sensitive to raising the CG. As you do things that raise the CG, the roll gets worse and it might start to snap on you. I had a friend who owned one with twin outboards, a hard top and a tower. It snap rolled so bad his wife would not set foot on it, even after they removed the tower. Bildgerat likes his twin outboards and doesn't have any problem with the roll. Make your choices, take your chances.

On the 250 vs the 300. I've never had either, so take this for what it is worth. The 300 will have a faster cruise,probably a bit faster than mine. As a 4 cycle, it should have more torque. Should be fine. Personal opinion, the 250 2 cycle is too light for that boat. I'd be astonished if it had the torque to act right at low planing speeds. Above 18 knots, it will be fine, just not fast.

The 25 takes more power than the 23, not because it weighs more, but because it is so much deeper. You pay for that ride with a less efficient hull.

cdavisdb · #9 05-19-2014, 09:00 PM

I assume you have read Stricks and Blue Herons rebuild threads and my " strange crack" thread. If not, read'um before you do any glass work forward. Also, for handling in rough water, read my Bahama threads. It got crazy a couple of times.

Bigshrimpin · #10 05-19-2014, 09:46 PM

On craigslist there is a 25 with a 225 etec and a notched transom. IMO a 250 EFI would be plenty of power. If my 25 wasn't so clean . . . I'd do the same and free up cockpit space. I got to ride in strick's 25 recently and it's very different from the 23.