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Author Topic:   Converting to Outboard from Stern Drive
Jinfun posted 10-02-2005 09:21 AM ET (US)   Profile for Jinfun   Send Email to Jinfun  
Have forum members removed a Boston Whaler boat's stern drive, filled in the transon, and converted to an outboard configuration? Is this possible? I've got an opportunity to purchase [an Outrage 19]. The current motor is an OMC which looks like it has seen better days and is missing its drive. The boat is literally sitting in the middle of a field. Thanks.
busted 15 posted 10-02-2005 10:12 AM ET (US)     Profile for busted 15    
hell yeah, got any pics,I see a custom setback bracket being installed,that would be sweet,fairly cheap,do a search
ratherwhalering posted 10-02-2005 10:29 AM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
This may help...

Jinfun posted 10-03-2005 09:30 AM ET (US)     Profile for Jinfun  Send Email to Jinfun     
Thanks for the encouragement guys. I'm going out today to have another look. Your link was interesting, but this boat has the true inboard powered stern drive with an entire GM motor inboard of the transom. Freeing up this area would definitely make the boat a lot for fishable. The motor and cover pretty well take up the the entire stern of the boat.

Would make an interesting winter project. Wife thinks I'm nuts. Will let you know how it goes. Hey fellow Canuck, whereabouts you from ?

banff22 posted 10-03-2005 10:14 AM ET (US)     Profile for banff22  Send Email to banff22     
He's up in the Britt area where I keep my 1984 Outrage 22. But I live in Brampton.

Good luck with the project.


banff22 posted 10-03-2005 10:31 AM ET (US)     Profile for banff22  Send Email to banff22     
I know I've seen more pictures of what you are looking for but I can't find them. Someone did the same thing, removed an I/O, then added a big bracket. An Armstrong I think. Try looking through these.


busted 15 posted 10-03-2005 11:12 AM ET (US)     Profile for busted 15    
ARMSTRONG thats the one. These are amazing. They not only look great but help with boat performance. Or you could have a local welding shop fab ya one up to your liking, either way you will be more than happy with a modern day outboard and be damn thankfull that OMC drive is gone. They where electric shift vertical drives and where NEVER any good. And now parts are 90 percent obsolete thank god,anyways throw some pics up on the board so we can have a look at her
captbone posted 10-03-2005 08:54 PM ET (US)     Profile for captbone  Send Email to captbone     
I would think that best choice would be to go with the new 1.7 Liter Mercruiser/Cummins powerplant with an Alpha one. I am an OB guy like most but that boat would be great with a diesel. That 1.7liter/120hp would be ideal for that boat with cruise in mid to high 20s with top 37-40mph. I also think that resale would be much higher than converting it to OB. Most people are careful about buying a converted boat. If you use it alot, it would pay off in the long run. I figured I would just throw this idea out there. Just my 2 cents.
jimh posted 10-03-2005 11:59 PM ET (US)     Profile for jimh  Send Email to jimh     
I do not recall any mentions of a conversion from a stern drive to an outboard. There have been conversions from OMC Sea Drive to outboard.

To convert to outboard you would need to:

--repair transom ($1,000)
--purchase and install engine set back bracket ($3,000)
--purchase 150-HP outboard engine ($12,000)
--re-rig entire boat for outboard including:
----steering ($1,000)
----shift and throttle controls and cables ($500)
----gauges ($500)

I think the total cost of this ($18,000) will exceed the cost of a replacement stern drive, which I think you could probably get for about $7,000 to $9,000.

I would not undertake this much of an investment in an older hull until I was certain I loved the boat, it was in excellent condition, and I planned to keep it a long time.

banff22 posted 10-04-2005 09:01 AM ET (US)     Profile for banff22  Send Email to banff22     
Jimh is probably right about no reference to an I/O conversion. I just have this picture in my head about a picture I've seen around here this last year. Maybe it's on a members website? Anyway, it was a heck of a good job as I recall.

But my main point of responding is, do not forget Jim is talking in US dollars and having the work done in the US. It could be, and probably will be, much more up here, so even less worth the effort on an older hull.


busted 15 posted 10-04-2005 09:26 AM ET (US)     Profile for busted 15    
yeah um and again maybe not,the I/O hole if your handy with fiberglass is not a big deal as it need not be perfect or pretty as the bracket will cover it ,the local welding shop fabbed my bracket up for 800.00 that included 24 inchs of setback enough to trim a V6 OMC outta the water, and a swim platform across the rear,no one says you have to buy a NEW outboard theres many mid-late 90s outboards to be had at a decent price,as for controls alot of these engines will come with them and guages I bought my 99 225 OMC with all for 4500.00 Canadian ,now on top of that theres Ebay,either way good luck and get same pic up
pglein posted 10-04-2005 12:20 PM ET (US)     Profile for pglein  Send Email to pglein     
The term you're looking for is "inboard/outboard" or I/O.

This may not have been done before, but I can't imagine it's all that difficult. The main concern would be properly strengthening the transom where the motor bracket will mount. This is critical. Otherwise, it would be relatively easy.

Although the conversion from I/O to outboard may not have been done on a Whaler before, the conversion from jet-drive to outboard has been done numerous times. Take a look at some of the threads regarding the Rage model, and scale your plans up.

LHG posted 10-04-2005 01:37 PM ET (US)     Profile for LHG    
Armstrong's sales literature has information on making a stern drive conversion to bracket. Check out their website.

If I remember correctly, there is much bigger hole to be filled in the transom, and would probably need to be professionally done. But it has been accomplished many times. When full transom brackets first hit the market in the mid 80's, this was one of the selling points, converting I/O's to outboards.

HOWEVER, with a 19' hull, you are pushing the minimum 20' recommendation for a transom bracket with 26" of setback.
I would think Captbone's recommendation to be a better solution and stay with the I/O.

Note that BW never developed a Whaler Drive bracket for the 18 Outrage, which I why I recommended that "ratherwhaling" only use a 12" jackplate on that Sea Drive Conversion instead of a 26" setback Armstrong

jimh posted 10-04-2005 10:51 PM ET (US)     Profile for jimh  Send Email to jimh     
Restoration of a hull "sitting in the middle of a field" is a project for someone with a lot of time available. If that fits your description, have at it, and pick a re-power strategy that fits your budget.

I do not think it is likely that a boat which has undergone a major conversion from stern drive to outboard will be likely to be a great return on investment if you try to sell it, unless you price all your labor at no charge.

placerville posted 10-05-2005 11:56 AM ET (US)     Profile for placerville  Send Email to placerville     
I have a 19' Revenge that was originally an I/O and converted rather poorly to an Outboard by a subsequent owner. After purchasing it and digging out the rotten wood and circular piece of plywood in the transom, I cut a
5/16" aluminum plate and bolted it to the inside of the transom. I then filled in the space with fiberglass resin and bolted on a CMC jack plate thru the hull and aluminum plate. Total cost was around $300. It's not real pretty but its solid.
Jinfun posted 10-05-2005 05:54 PM ET (US)     Profile for Jinfun  Send Email to Jinfun     
OK guys. I went out and had another look at the boat and bought it (wife's not too pleased), it has hull number 00563 stamped on the step pad at the front port side of the boat. The floor and transon under all the dirt, leaves and branches actually looks to be in pretty good shape.

Here's the Chinese/Jewish part of me coming out. I've got a 90 hp Nissan OB in good running order sitting in the garage gathering dust and a good amount West Epoxy/glass left over from another project. I'm thinking a manual aluminum setback bracket would be about $250 :). On the water for next summer ?

I'm almost embarassed to tell everyone what I paid for the boat. The owner is even going to hoist out the existing motor for me. The area around the motor well has some raised stringers so I was wondering what would be the best way to fill the cavity in. Could I re-use the existing motor cover by cutting it shorter to fit ?

I've never posted photos at a site on the web but will try tomorrow so everyone can have a look.

P.S. Sorry Jim, but I've started a thread in marketplace also. Will let it die.


seahorse posted 10-05-2005 07:58 PM ET (US)     Profile for seahorse  Send Email to seahorse     
On the subject of changing out a stern drive and installing an outboard, I had the chance to setup and run a 21' Tiara that had a 215hp V6 removed, and an Armstrong bracket installed with an Evinrude E-TEC 225 outboard.

After an initial run and some prop swapping, we ran over 54mph compared to 45 with the stern drive. Most of the ones I've been involved with over the years shows a 10mph gain on the average.

The owner can still play with engine height and prop design for absolute top speed as we settled on a Viper 21 for all around use.

The E-TEC rig is now quieter than the Mercrusier stern drive it replaced and has a lot more acceleration, mostly due to less weight in the boat. The owner is happy, and that is what counts.

busted 15 posted 10-05-2005 08:52 PM ET (US)     Profile for busted 15    
JINFUN come on with the picks and how much ya get it for spill it man lol
Jinfun posted 10-06-2005 02:21 PM ET (US)     Profile for Jinfun  Send Email to Jinfun     
Forgot to say hello to my fellow Canucks. I'm near Caledon East and building a cottage at Shawanaga Bay. Anyways, I've posted the photos at

user: waiyut88 password: jacob8

As you can see, the boat's really dirty. Any suggestions are welcome. It's a clean slate for now. Will be picking her up next week.

P.S. I paid $750 Canadian funds

banff22 posted 10-06-2005 03:02 PM ET (US)     Profile for banff22  Send Email to banff22     
Great pictures. Gives everyone an idea of what you ended up with.

Caledon East, that must be all of 20 or 30 minutes from me. I'd love to see the boat up close when you have it all organized.

Good Luck.

Oh. BTW, I tried to email you 'cause you had my curiosity up as to where you the boat around here but it was rejected. You might want to check your address.

banff22 posted 10-06-2005 03:03 PM ET (US)     Profile for banff22  Send Email to banff22     
That should *where you found the boat*


busted 15 posted 10-06-2005 05:46 PM ET (US)     Profile for busted 15    
mmmm hmmm nice find if its still solid and the foam hasent seperated from the hull too much thats gonna be a great G-Bay boat man,get er home clean er out and post some more pics,I think 750 was a steal ,by the way what pointe au baril contractor is building your cott on Shawanaga Bay,your gonna need a good boat out there, theres always rollers
jimh posted 10-06-2005 11:41 PM ET (US)     Profile for jimh  Send Email to jimh     
Just post the URI to the photo images. It is not a good idea to post your user-id and password.
Jinfun posted 10-07-2005 08:44 AM ET (US)     Profile for Jinfun  Send Email to Jinfun     
Thanks for the advice Jim. First time I've posted pics. I guess I'll have to ask one of our IT guys what a URI is first and will do it that way. As you can tell, I'm a bit of rookie at it.

Hello Placerville. I'm very interested in how you dealt with the motor area. Did you fill it in or just cover it with a hatch ? I noticed that there are 5" and 10" setback brackets, which would be better ?

Hey Busted, I'm doing the work mostly by myself for the last 4 years. Started with a bare lot (it's at least a drive to lot). Almost killed myself doing it. Shingling in the snow is not fun. It's a beautiful area and a great place to recharge the batteries after a stressful week at work.

Will try and properly post pics of the cleaned up boat in about a week or so. Cheers guys.

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