See full version: Thread: Converting a boat from inboard to outboard
I wasn't being facetious, Reynard38; I'll guess that you meant it as a question. The answer is commonly put that a hull that has a flat aft run, can generate enough hydrodynamic lift at speed to physically lift the hull partially out of the water, and can move through/over the water at a rate of speed between 2.5 - 3.0 times the square root of the at-rest waterline length is generally considered an planing hull.more
Naturally, I defer to, and eagerly await, MMD's commentary to any further info you provide. That said, Ive seen a few of these conversions.here
I've also seen non
-planing hull inboard boats converted to outboard. Substitute ballast and a bracket as above, but the handling and ride ( bow high attitude, poor directional stability) here
Its an old statement that given sufficient thrust even a brick will fly. Not well, but it will. more
I know of quite a few smaller offshore boats, under 30’ that would work great because re-powering with big blocks and drives can get pricey and they often respond really well to the weight further aft and being lighter overall. Outboards are so reliable and easy to maintain now, this is a great option on some boats.
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Many center consoles use brackets, like this Concept 35, and are often based on old offshore hulls
With the Evinrude G2 clean rigging, you get a very uncluttered transom and utility.
Armstrong brackets are common on all types of boats and are often OE suppliers. [links]
There has been a few surprises at recent boat shows where very traditional manufacturers modified existing models, or introduced new models to accommodate outboards. Big manufacturers like Regal and Formula offered some family boats and cruisers converted to outboard and performance offshore orientated builders like Cigarette and Outerlimits started adding outboards to their lineup; Cigarette with newly designed center console boats and Outerlimits converting an existing hull. Others like Saber Marine, Checkmate Boats and Active Thunder have been doing it for a long time. The advantage being turnkey efficient power from modern outboards, ease of maintenance, cost and performance. Outboards have many advantages. Die hards will reminisce about the rumble of a V8 or the song of multiple V8 engines running in unison. But, even those guys might convert when they pull up to the gas pumps, or need to pull an engine for repair.
PDR Marine Fabrication can build a bracket for any purpose for your boat. We build transom brackets to fit the transom of your boat for your outboard motor to be mounted. We build these for boats as a standard item from the factory as well as for boats that are being repowered from inboard power to the efficiency of today’s outboard motors. An outboard transom bracket can be customized to fit one or two motors and include such options as additional flotation, 3/4 or full platform, port or starboard auxiliary motor mount and add a dive ladder. here
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" . Mark42, what do you think? Did I hold my own. "<br /><br />I think you did it with style and class, my friend.
just sold a 96 18' Aquatron for the reason you are wanting to make this change, i bought and older 18' Bonita and put a 135 Merc on it i get the same performance, as with the 190hp 4.3L V6 i/o. gas is about the same. just a lot more usable room. more
I dont know about the other people on here but my 73, 135 Evinrude is a real pig on fuel compared to my 252 Buick V6 on a 16 Correct Craft , I would guess it uses almost twice as much, but the 252 is a strait inboard, with a high performance cam and a four barrel. They came a long way on outboards and I know both of mine are antiques but I would do a lot of research before I went to far if it were me. The 135 is on a 17 Bonito deep V, its been bored 90 over and does 35 to 37 GPS MPH depending on current and load, I usually have two people on board. The 252 Buick will rip a skiers arm out of their socket if your not careful on take off and has more torque then it can ever use! here
I doubt there will much of a difference in fuel economy. As far as power goes, I think the 115 would do, but it will be working hard! Have you considered looking for a used Sea Drive? more
The other thing is the cost,It would be much less money to sell yours and buy what you want, plus you will be back on the water in a few weeks, not next year. I can say this because I've done it, it took about 4 months to finish, 2 of those months were between jobs so I could work on it all the time.
Re: Converting Inboard to Outboard