is it possible to use an outboard with an inboard or i/o boat?

littlebunker

Seaman Apprentice
Joined
Dec 6, 2013
Messages
33
I am looking into possibly getting a new (used) boat. I'm hoping to step up to a larger boat (thinking in the 20-25' range), and most of the ones I'm seeing in my area are inboards or i/os. So, I have two question:

One, inboards are all fine and dandy, but I've had the "two is one and one is none" mentality beaten into me, and since there's no way to bring an extra inboard along with me, I'm looking into alternatives. I've seen little kicker transom plates on sailboats and stuff, but are these able to go on basically any boat? Also, they look weak, and like they're designed for small, small motors. Right now, my "backup" is an old, heavy 25hp. If I stepped up, I'd want my backup to be a 40 or something. Pretty sure these sailboat transom plates aren't designed for that kind of stress. So my question is, IS there something that IS designed for larger, more powerful engines? Something I can just bolt on?

Second. I actually just don't have much experience with inboard or i/os. An old 2 stroke outboard I can rebuild in my sleep so I'm just more comfortable with outboards in general. Is there some product that is meant to be a permanent bolt-on transom? I assume people have converted, but I don't know how much of a project this would be. I am also seriously considering aluminum boats, and this seems like a much bigger undertaking than with a fiberglass boat where, theoretically, you can just build a transom out of fiberglass and glass over the engine hole. But, when it comes down to it, I'd much rather but a boat with a sound hull and a broken motor for cheap, and then spend the rest of my budget on putting in a solid transom than spend equal amounts on a boat with a working i/o. Am I crazy for even considering this kind of conversion?

Any thoughts are welcome, thank you all.
 

Old Ironmaker

Captain
Joined
Dec 28, 2015
Messages
3,050
I haven't seen a 40HP kicker, that's not to say they don't exist on larger boats. All the kicker plates I have seen from Marinas have a max weight of 120 lbs, the size of the kicker would be dependant on the width of the transom I would think. I have seen home made conversions from I/O to outboards, most home made and not pretty. Why not just look for a good 20 to 25 foot boat with an outboard and mount a 25 HP kicker as your back up, they are out there. I have seen 30 foot offshore rigs with triple and quad outboards. Many 20 to25 foot I/O's have 20HP kickers that work well. A friend has a 24' Bayliner Cuddy and his 15 kicker moves it well enough to get back to shore. He has had to do that a few times this season unfortunately. Weight and stress on the transom with a kicker is the issue. With a kicker plate that extends beyond the transom would create even more stress.

You mention the word "cheap", no such thing when in the same sentence with boat or marine. As far as being crazy to think about converting an I/O to Outboard, crazy is based on your fabricating skills. No fab skills, yes you are certifiable.
 
Last edited:

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I don't see any problem turning an inboard transom to an outboard setup. If you know the mechanics of fiber-glassing the inboard hole through the transom to the point that you can fill that hole and make it look like there was never a hole there, then I can see that working. But you have to also make that transom solid as well and not just eye candy. Then installing your favorite outboard or even duels would be merely setting them up with the steering cables. That way if one engine comes down with a case of "I am not going to run anymore", you still have the other to get you wherever you need to go. Sounds doable to me. JMHO
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
24,829
It is more involved then simply glassing an outboard notch into an I/O or inboard boats' transom.

Doable, sure. Easy? Nope. Has it been done? Yep. Were those conversions successful? Dont know, few if any, of those members have come back at all, let alone w great news of a successful conversion.

Would I? Nope.

Buy an outboard boat if you want outboards.

IMO, the above all applies equally to I/O conversion to outboard pod/bracket setups.

Google

outboard pods and outboard setback brackets

These are a larger brackets for larger (which are heavier) HP motors 'equal' to small kicker motor brackets you've seen on sailboats.

And again, they arent simply bolt on and go for an I/O hull and have also been done w little feedback from those members after a season or 2.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Any size motor could be considered a kicker, it just depends on the boat it's being attached to.

You can easily bolt a kicker bracket on the transom of most boats, but not all, so it will depend on the exact boat you buy. The normal kicker for a boat of that size is 15hp or less, but this depends on where you go boating, and we don't know that bit of info. 9.9 high thrust kickers are the most common.

Once you throw "cheap" into the equation you eliminated yourself from this category of boat, nothing about buying, fixing or modifying a boat of this size is cheap.
 

littlebunker

Seaman Apprentice
Joined
Dec 6, 2013
Messages
33
hey everyone, just to clarify, when I said "cheap" I didn't mean "no money". I was just trying to express the idea that a boat with a broken motor is cheaper than one with a working motor, yeah? So I'd rather spend less money on a boat with no motor, and put the rest of that money into fabbing a transom.

Or, at least, that was the idea. Your comments are making me rethink! :)
 

southkogs

Moderator
Staff member
Joined
Jul 7, 2010
Messages
14,785
What kinda' water are you boatin' on? If you're on big water (ocean, great lakes, etc.) I can understand the dual setup motif. But if you're inland I'd suggest that you're in MUCH better shape to look at one of the I/Os and a tow service plan.

I transitioned to I/Os a few years ago ... and honestly there's pros and cons to either setup (OB vs IO)
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Straight inboard motors are horrible for shallow water. However, they do have a full transom where you could mount a jackplate for any size outboard you want. You will want to mount it so the outboard doesn't drag in the water when cruising, or better yet if you can tilt it up.

​I/Os, are much better in shallow water, as you can trim and tilt them. They tend to have less transom space to attach a jackplate. There are bolt on kicker motors (~15HP max) that you could probably use. They bolt to the swim platform or hull.

​If it were me, I would make sure the motor is maintained and is going to get you home, and buy towing insurance just to make sure.
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
If you can't find the boat you want locally then look in other locations, a several hour drive is much cheaper and easier than a several month rebuild of a hull designed for another drive system. The conversion can be done, but the cost and hassle for a DIY project is more than most people want to get involved in. If done correctly the conversion can work out very well, but it?s still a costly hassle.
 

midcarolina

Chief Petty Officer
Joined
Jul 16, 2013
Messages
631
There are more than a few video's on youtube on this very subject...There are company's that manufacture the pod to convert from stern drive to outboard.
But seems to me it would maybe be cost effective if I had a very good outboard of the appropriate HP just sitting around and then found a boat I couldnt live without.....
 

Ned L

Commander
Joined
Sep 17, 2008
Messages
2,266
When talking about a true "inboard" (not an 'I/O"), keep in mind that the transom really has little or no structural strength, because there are no propulsion stresses on it.

Hmmmmm,....... so worried about two engines? Do you have two in your car????
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,310
Good maintenance and towing insurance is more reliable and less expensive than hacking a hull to install pods and mount two large outboards
 

garbageguy

Lieutenant Commander
Joined
May 8, 2012
Messages
1,531
+1 on the above

Yes, it can be done
Also, consider the considerable change in boats in the size-range you're contemplating
 

rallyart

Lieutenant Junior Grade
Joined
Jun 7, 2008
Messages
1,175
Nobody has mentioned it yet but a 40 hp kicker would be no better than a 20 hp one on a 20' plus boat. It will only travel at about 6 mph tops as you won't get on plane and will only be churning the water and burning gas with more power. A 9.9 might do you fine in an emergency.
I would assess if you really need a second engine and, if you do, get a hull designed for it. Mods cost more that no mods.
 

Old Ironmaker

Captain
Joined
Dec 28, 2015
Messages
3,050
[
Hmmmmm,....... so worried about two engines? Do you have two in your car????[/QUOTE]

Good point, but if my car died during a storm I just pull over to the side of the road and wait her out nice and dry until help comes, not as doable in the boat.

I hung a 15 horse kicker on for just that reason, a back up. I don't need it to troll.
 
Top