[SPLASHED] I/O (Sterndrive) Conversion to Outboards

[redneck joe]

side note, about time to plan for the pic to update your sig line - and how to concisely describe this thread in 10 words or less...

 

[flashback]

I might be wrong,but I think Honda made the first 4 stroke outboards many years ago, I had a 7.5 bf75 on my old sailboat in 1976. Probably still running.

 

[racerone]

I believe Lauson made a 4 stroke in the late 1940's.

 

[flashback]

I believe Lauson made a 4 stroke in the late 1940's.

Never heard of them, how were they, probably a bit troublesome I'd guess.

 

[tpenfield]

I should be able to 'test' the boat at higher speeds tomorrw, even up to WOT. I'm thinking somewhere in the 52-54 MPH range. What say y'all?

 

[tpenfield]

Now that this project is winding down, I took a look at the overall cost of the conversion project, for the benefit of anyone else crazy enough to consider such.
.

.
Of course, without the Honda instant savings promotion, the cost would have been $20K more.

 

[tphoyt]

Yeah but you got a sweet ride out of it and it’s the way you want it be. You only live once right.

 

[jlh3rd]

and you know it inside and out.

 

[redneck joe]

what was original WOT?

 

[flashback]

what was original WOT?

He has the same hp. So I'd guess about the same top end. The added length might be a factor.

 

[Pmt133]

He has the same hp. So I'd guess about the same top end. The added length might be a factor.

Dual props add a lot of drag up top though

 

[redneck joe]

and aren't we about a couple five hundred lbs lighter? And newer technology at the powerhead? I know hp is hp but I/o and OB are apples and oranges - both fruit but i would not bake an orange pie.

 

[redneck joe]

Dual props add a lot of drag up top though

'up top'? you mean on the WOT part of the scale?

 

[Pmt133]

'up top'? you mean on the WOT part of the scale?

Yeah. They're better at cruise but a couple mph slower at wot in my experience.

 

[tpenfield]

The boat is about the same weight as before, because the engines and bracket are heavier than originally planned.

Top speed as a sterndrive boat was 45 mph. I'm thinking it will be 8 mph faster with the extended hull and outboards.

 

[Pmt133]

These are 19s you're running?

My guess is ~52 MPH assuming it was propped for middle of the WOT range.

Any faster than that and you may force me to drop a 350 in my boat on principle.

 

[tphoyt]

I’m waiting for the fuel economy numbers. That will be very interesting to me. I’m guessing you will be saving quit a bit on fuel cost.

 

[jlh3rd]

$20,700 +/- (not including labor) just for the addition. Just goes to show why a boat can run into 6 figures easily, and what it takes for engineering and design.
Impressive work.

(edited)

 

[Scott Danforth]

I’m waiting for the fuel economy numbers. That will be very interesting to me. I’m guessing you will be saving quit a bit on fuel cost.

there is no fuel economy on a boat unless you have sails or oars......