Your input on Outboards
03-03-2013, 08:22 AM
#11
21 and 42 footers
Platinum Member
consider that he'd have all of his old running hardware to re-sell to offset his investment.
As far as glass work, a couple of transom knees would probably be it besides glassing in the I/O holes. The knee's are fairly easy as you can do 90% of the fab work on your bench then just tab them in. Cardboard patterns and off you go.
Plugging the holes would be making a pattern, several layers of 3/4" ply, several layers of 1708 cloth and you're done. One side is hidden in the bilge and the other by the bracket too.
Bolt a bracket on and you're ready to rig.
IMO, the re-rig would be the most work.
He'd end up w/the same power at at least 1000lbs less and 50% more storage.
That conversion down here is huge and becoming more and more popular.
As far as glass work, a couple of transom knees would probably be it besides glassing in the I/O holes. The knee's are fairly easy as you can do 90% of the fab work on your bench then just tab them in. Cardboard patterns and off you go.
Plugging the holes would be making a pattern, several layers of 3/4" ply, several layers of 1708 cloth and you're done. One side is hidden in the bilge and the other by the bracket too.
Bolt a bracket on and you're ready to rig.
IMO, the re-rig would be the most work.
He'd end up w/the same power at at least 1000lbs less and 50% more storage.
That conversion down here is huge and becoming more and more popular.
The weight savings it great but the problem with all that additional storage space is stuff finds it's way in there.....permanently! Weight savings soon disappears.
Being you already run a twin O/B V-hull, what are your performance/fuel numbers for comparison? My post above highlights my OPINIONS, but not fact. Love to see some real world numbers.
I'm not knocking O/B's, I actually wish more boats were built this way. I'm just not yet convinced a conversion is the best way to get one.
03-03-2013, 08:24 AM
#12
I love the sound of those big blocks....To me thats what high performance boating is all about! But............. I went with outboards. For what I have in my boat (that has not hit the water yet) I could have easilly gotten a I/O boat. Around here the outboard guys are out every weekend. Pull up, flush & put it up for next weekend. The high hp boys are allways under the hatch and to me don't enjoy their boats as much.
With that being said.....If I were you I would wait for a outlaw with toasted motors and start from there. I think it would cost too much and not be worth it to do a conversion with a good running boat. Find a hull, buy a pair of mercury 300xs's and run up there in the 70's
With that being said.....If I were you I would wait for a outlaw with toasted motors and start from there. I think it would cost too much and not be worth it to do a conversion with a good running boat. Find a hull, buy a pair of mercury 300xs's and run up there in the 70's
03-03-2013, 08:45 AM
#13
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How heavy is your boat? I hear many people say what you are saying, but, I've never seen real world data to substantiate the claims. There's no " replacement for displacement" an engine stressed uses more fuel to achieve the same speed- you have to push the throttles to stay where you want to be. A 2.5 liter outboard is going to burn more fuel pushing my 28' Pantera than a 6.2 liter SBC. Outboards have gotten better and bigger, hell you can now strap a V8 small block 350 Yamaha to the back of your boat, but I don’t think you save fuel. That said if anyone's got actual data showing something to the contrary I'd love to see it- I think we all would. Take the $$ for this project and throw it in a jar to buy gas.
03-03-2013, 09:45 AM
#14
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My 22' deep v CC with a 225 optimax only gets 4mpg on a very good day. That's on offshore fishing trips staying at 3800-4000 rpms trying to save gas. I don't know what twin 300's on a 29' would do, but 3 mpg would be at the high end of the scale in my non professional experience.
03-03-2013, 10:27 AM
#15
It would be beneficial to all just to get an accurate estimate of the work and $$$ needed for such a conversion. The extra space would indeed be a great feature. While I have no idea of the work required and the $$$ needed, another more obvious setup would be to replace the current power with diesels. Given the OP's boat is a '99, you'd really have to keep this boat a long time to appreciate the $$$ invested. But I would imagine it's far, far cheaper than the alternative.
Another thing that comes to mind is the setup of new boats. While some brands have definitely delivered more and more OB-powered boats, they seem to assume everyone wants a CC. This might be due to the fact that it's the current In thing to build. But one of the reasons people like the CC's is space. Cockpit space to move around, and actual seats for people. Obviously, when you see 38' boats with bolsters and a few coffin chairs, the boat is setup for a single purpose. But you rarely see people enjoying themselves in the cockpit hanging out.
I see that Checkmate has a 280 OB, and Active Thunder has a 33 OB, which could be compared head-to-head against their stern-drive 33. Neither boat looks maximized for space with outboards, but the 33 is a very big boat compared to many.
Not many outboards in the used markets yet for this segment, and from the models available now, it looks like it will take another 10 years to get a good inventory.
Given you have twin 330's, it would be interesting to see what the experts would say regarding the weight issues. You'd have less total weight with the twin outboards, but they would be much further back. Does anyone know how this 29' hull would deal with those type of weight shifts?
Another thing that comes to mind is the setup of new boats. While some brands have definitely delivered more and more OB-powered boats, they seem to assume everyone wants a CC. This might be due to the fact that it's the current In thing to build. But one of the reasons people like the CC's is space. Cockpit space to move around, and actual seats for people. Obviously, when you see 38' boats with bolsters and a few coffin chairs, the boat is setup for a single purpose. But you rarely see people enjoying themselves in the cockpit hanging out.
I see that Checkmate has a 280 OB, and Active Thunder has a 33 OB, which could be compared head-to-head against their stern-drive 33. Neither boat looks maximized for space with outboards, but the 33 is a very big boat compared to many.
Not many outboards in the used markets yet for this segment, and from the models available now, it looks like it will take another 10 years to get a good inventory.
Given you have twin 330's, it would be interesting to see what the experts would say regarding the weight issues. You'd have less total weight with the twin outboards, but they would be much further back. Does anyone know how this 29' hull would deal with those type of weight shifts?
03-03-2013, 12:35 PM
#17
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Concept makes a nice 30' sportdeck OB.
Powerboat test 78.4 mph - with 300s, plus enclosed head.
http://www.youtube.com/watch?v=9nAQJca_M44
Powerboat test 78.4 mph - with 300s, plus enclosed head.
http://www.youtube.com/watch?v=9nAQJca_M44
03-03-2013, 12:36 PM
#18
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28 Checkmate with twin Mercury 225 outboards. 70 mph and 3 mpg.
http://www.offshoreonly.com/classifi...o40299-en.html
http://www.offshoreonly.com/classifi...o40299-en.html
03-03-2013, 12:42 PM
#19
21 and 42 footers
Platinum Member
also.....a buddy sold a 35 Cafe Racer with twin 540's and bought a 28 Boston Whaler CC with twin merc 225 (older carbed).......claims he gets the EXACT SAME mpg the Cafe Racer got, 1 mpg.
03-03-2013, 12:43 PM
#20
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I like the comment about the 33' PP O/B's. I was actually thinking the same.
Theres one thats been for sale down here, forever w/twin XS's for I think $48K.
T500, I don't have accurate #'s on mine yet. Still tuning the motors and figuring out my fuel monitoring system. My best guess on my old 24' O/B w/stock versions of same power was about 2 MPG's @ cruise.
Remember too though, that's old school carbed motors and the new DI 2 strokes are between 40 - 50% more efficient. That would put me over 3 mpg's if my guesstimates are close.
BRP has a site to figure fuel savings on repowering w/their E-Tec's. At $3. per gallon I was saving $500. every 3rd tank based on their math. At $4. per gallon that savings goes to $650. per 3 tanks or $220. per tank @ 90 gals!
Theres one thats been for sale down here, forever w/twin XS's for I think $48K.
T500, I don't have accurate #'s on mine yet. Still tuning the motors and figuring out my fuel monitoring system. My best guess on my old 24' O/B w/stock versions of same power was about 2 MPG's @ cruise.
Remember too though, that's old school carbed motors and the new DI 2 strokes are between 40 - 50% more efficient. That would put me over 3 mpg's if my guesstimates are close.
BRP has a site to figure fuel savings on repowering w/their E-Tec's. At $3. per gallon I was saving $500. every 3rd tank based on their math. At $4. per gallon that savings goes to $650. per 3 tanks or $220. per tank @ 90 gals!
Last edited by Twin O/B Sonic; 03-03-2013 at 12:49 PM.
