27 Flybridge conversion from I/O to Outboard

[3rdday]

Thank you all everyone- Sandy,Denny, FR Frank, Joel, Captbone, No Bones, Ryan and everyone else who has contributed.

Just needed a little sanity check against the theories.( bracket set back 10-15% improvement, boat will be 13% lighter, two stroke fires on every compression stroke)

I'm betting you are right in the Mirage, as Fr Frank, Sandy, Denny and others have speculated the same/ similar. I read in the post that Denny provided with the guy running the 30' with etec 300; that the 4 blade robbed forward thrust power was bled off to stern lift versus forward movement...so I'm thinking a 3 blade- I Have both here now a 3 blade 15 pitch House Mouse Ear blade style (credit Sandy) and a 4 blade that was designed and built by Halls-Mike Hall- Ill try them both and see. I think if the three blade doesn't do well ill have some cup added its a little flat in the ass, and test her out.

I will be posting pics- soon probably starting tomorrow.

[captbone]

Any updates?

[3rdday]

Here are a couple of photos.
I need opinions;
One pic- the one with the rear (engine side) of the bucket angled down is flush mount.
The other pic is with the bucket almost straight out. I would be able to shim the bucket.This would bring the engine higher out of the water but still in effective operating range.
In either case the engine will be able to be moved in operating range. Large Hydraulic Jack Plate.

Im asking because I dont like the appearance of the back angled down, but this is how they fit on a dusky also. The advantage of this would be more of the bucket submerged offering more flotation.

Originally Posted by captbone

Any updates?

[Rlbol]

Are you going to run a single outboard? I couldn't imagine what the fuel burn as well as performance would be like? My 23 with that bracket and a 250 ox66 is decent but I bet that hull ways at least a 1000lbs more. You are also not going to gain much if anything of floatation with that bracket looks more like drag. I would ditch that bracket and spend the money on a hermco floatation bracket! Good luck. I just don't think that bracket with the biggest single outboard would do that boat any justice.

[77SceptreOB]

I'll would think the operating angle of the engine would not work at the angle the bracket appears to be in the second photo. I don't think the trim portion would go that far and compensate for that angle. Probably be up into the "tilt" area, which would be unsafe to operate at speeds above 5 mph.

I'll bet a Yamaha 350hp V8 would do the job fine...

[3rdday]

Thank You Gents, Much to consider, especially the trim range/Angle.
Yes the Yamaha 350 might, but its allot heavier.
I was just going to experiment with this for the purpose of running a single.
If I can't get decent performance Ill probably go with twin etec 175 or twin 200 etec.
It's nothing for me to unblolt, do some composite work, and re-bracket , childsplay!!

Originally Posted by 77SceptreOB

I'll would think the operating angle of the engine would not work at the angle the bracket appears to be in the second photo. I don't think the trim portion would go that far and compensate for that angle. Probably be up into the "tilt" area, which would be unsafe to operate at speeds above 5 mph.

I'll bet a Yamaha 350hp V8 would do the job fine...

[gofastsandman]

Originally Posted by 3rdday

Thank You Gents, Much to consider, especially the trim range/Angle.
Yes the Yamaha 350 might, but its allot heavier.
I was just going to experiment with this for the purpose of running a single.
If I can't get decent performance Ill probably go with twin etec 175 or twin 200 etec.
It's nothing for me to unblolt, do some composite work, and re-bracket , childsplay!!

Much to consider indeed.

Denny has shown that you can mount an engine much higher than the norm on a VDH hull w/ a
large flotation bracket.

Carl opined, why not make a bracket follow the running surface of the hull as already designed?

How much travel does the jack plate allow?

I saw the new Ocean Master 27 cc hybrid at the show 3 yrs. ago. Rigged with twin 150 e tecs.

Mark said it would hit 50 light and plane off on one engine.

Please post audio of the V8,
GFS

[DonV]

Hey Sandy, I've got a friend who has one of those V-8 350 hp Yamahas. At "full song" it makes a very loud fuel sucking noise....very loud. I'm not sure a 3/8" fuel line is big enough.

[3rdday]

Here Ya go Sandman.
Music to your ears!!!! and Mine too.
http://www.youtube.com/watch?v=GcrpMbSXWF8

[captbone]

You will not need any additional flotation with the single. I would highly recommend mounting it level on top like in the first picture.

Here is a great read about a similar project. Like myself, this gentlemen needed to add weight to the rear and not floatation. I have an 8D battery against the transom to get it level. I suspect you will have the same issue.

http://simplifying.net/phpbb/viewtop...er=asc&start=0