I/O (Sterndrive) Conversion to Outboards

[jlh3rd]

"and we shall see how it all works out in terms of the boat performance "

that's the million dollar question.

 

[redneck joe]

i think he is actually in for under $100k....

 

[Pmt133]

Do you have a proposed set of metrics to assess boat performance? Or is feels good enough, good enough?

 

[redneck joe]

feels good is always enough.

 

[tpenfield]

Do you have a proposed set of metrics to assess boat performance? Or is feels good enough, good enough?

The happiness meter will include the following inputs . . .
.

 

[Pmt133]

Makes sense, fuel usage is always smiles per gallon anyway.

 

[redneck joe]

explain the trim metrics; not familiar.

 

[tpenfield]

explain the trim metrics; not familiar.

Trim is the angle of the keel vs. water level. So, a zero angle would be even with the water level. Generally, you want a slight upward angle at rest and not too much upward while underway.

I’m hoping for a slight up angle at rest (0.5-1.0 degrees). And less than 3 degrees underway. The Naval Architect modeled a 7 degree bow rise coming out-of-the-hole and about 2 degrees at WOT

 

[tpenfield]

Speaking of WOT . . . In discussing propeller pitch with the re-power shop we came up with a 19” pitch as the starting point (19 x 16). Estimated top speed would be in the 51-53 mph range if the engines can make their WOT speed of 6,000 RPM

 

[Scott Danforth]

if the engines can make their WOT speed of 6,000 RPM

Nitrous will help

 

[Pmt133]

I've heard anything can take a hundred shot once.

 

[redneck joe]

so your current sig pic looks like an aggressive at rest angle?

 

[tpenfield]

so your current sig pic looks like an aggressive at rest angle?

Looks so . . . I did not measure it. There will be an additional 2,000 lbs of buoyancy from the extension bracket. I expect the stern to be up a 'wee bit'.

 

[redneck joe]

i bet it will only be a 'tad'...

 

[Pmt133]

When I removed all the water logged foam on my boat I expected the thing to float higher. It did not.

I recall discussing the CG change a while back. How much did it move? I feel that's going to dictate quite a bit. Then all the extra beer storage is going to effect the angle as well.

 

[tpenfield]

The CG (Center of Gravity) . . . as best that I could calculate . . . is going to move about 12" aft and 5" upward.

The Savitsky analysis done by the Naval Architect showed the boat would be at only a slight upward angle at rest (0.3˚).

Some folks do a live test of the boat before the engines are rigged, but most tend to just wing-it and see how it floats once fully rigged.

 

[redneck joe]

so you are going to 'wing it'. Got it...

 

[tpenfield]

so you are going to 'wing it'. Got it...

wing & a prayer

 

[Pmt133]

Accurate description of my entire rebuild.

 

[Lpgc]

Been following this thread a long time, looking forward to seeing pics of it on the water and hopefully reading how happy you are with it @tpenfield . Best of luck!