Dual engines possible

[DarrenPayne]

Hello all, Im new to the Forums and new to the boating world. I have been looking into finding an older gently used 18-20 foot bowrider boat. I have alot of questions about boats period. I have a specific idea in my head for what I want to do, But having a very hard time tracking down real information. First off, is it possible to buy a boat with a single engine (inboard/outboard) and modify the transom ( i beliave thats what the rear of the boat is called) to accept two engines and to final drives ?? Are hulls desighned around the engines ?? I took mesuremets on several boats and all will fit two engines with accecories ( tightly). I have no real reason why two engines is better than one, but its just what I want to do. I have read and researched several web sites about repearing and replacing transoms but im still in the dark. Can one cut out that part of a boat and replace it with a dual final drive set up ?? I know its going to require alot of of work and fabrication with all the other parts involvedm steering, engine mounting ect ect. Thanks for any help and ideas. I may be spitting in the wind with this idea

[marshmat]

It is possible, but it's extremely difficult to get the transom strong enough. You can't just patch the hole as the entire transom is structural. While you can cut out a transom and replace it, it's really not practical unless it's already rotted out.

You will not find any 18-20 foot bowriders with twin sterndrives. Virtually all of this class is single sterndrive or single outboard; a very rare few are twin outboard. A hull this small simply can't take that much weight in the tail. Twin 3.0L 135hp motors (the smallest sterndrives available) are heavier than a single 250-275hp V-8. With the extra weight an 18-footer will just squat and stick its bow up in the air when running. (Notethat most boats in this class have either the 135hp 3.0 or the 190hp 4.3 engines as standard.)

You can get all the handling benefits of twins with a coaxial sterndrive such as a Bravo 3 or Volvo DP. This might be an ideal solution for you, a single larger engine with a coaxial drive.

[DarrenPayne]

Thanks for the reply Marshmat. I had a feeling it proably would not be possible. The new master craft X-80 with twin 5.7 liter engines is a aswome looking ski boat. Kinda what got me on the dual motor kick. To bad I cant just hand out 50k for one or I would be set :) What exactly is a coaxial drive ?? Thanks agin for the reply

[marshmat]

A coaxial sterndrive is simply a sterndrive with two propellers on the same shaft, spinning opposite directions. The Volvo Duoprop line is the definitive example.

About the X-80: This is one heavy little porker of a watersports boat. It gets away with its engine arrangement by mounting motors farther forward than is normal with sterndrives and by having far more buoyancy aft than most boats of its class. Nice boat to be sure (if you're a wakeboarder), but the concept doesn't adapt too well to traditional hulls.