Questions regarding an unorthodox drive layout.

[Ji Simmons]

Hi folks. I'm not really sure how to start, so I'll just tell you all the whole story...

I like to build and own unique things. My cars, my bikes, my guitars... all rare and somewhat unorthodox. I've been itching to build a boat, and it's looking like this winter will be the build season for me. I'd like to build a 15' two person boat that will see calm, freshwater use. As for a hull design, I'm pretty much set on that, but the propulsion is still up in the air. An outboard would be fine, but I feel that it would spoil the lines of what I've drawn up, and would like to go with an sterndrive or inboard. Now, at this point, I'd like to mention that I'm a cheap bastage. :-p Anyway... I have a '99 Chevy Metro four cylinder engine laying around, and would like to use it in conjunction with a turbocharger (how that all will work has been figured out). The engine stock makes 79 HP, and with the turbo, I calculate 150- 180 HP, depending on several factors that aren't important here.

Anyway... the questions are... are there any simple F-N-R inline or L (or Z?) drive transmissions out there that are cheap and designed for said power output?

Or... If I were to use an outdrive from a sterndrive, but have it fixed and attached to the bottom of the hull just fore of the stern, and have a movable rudder at the stern, how would that affect the handling of the boat? To clarify, the lower unit of the stern drive would be below the keel, and the upper part would be inside the boat, coupled to the engine. It would not be trimmable or steerable. Steering would come from a rudder directly behind the prop, and all this would be as far aft as possible. The reason for doing this and not a conventional stern drive is because, again, I'm a cheap bastage and can pick up used Alpha 1 outdrives for $150- $300 at my local marina, but the gimbal, trim pistons, and pump put the price upwards of $800. I prefer this method over a conventional inboard because it would give me a transmission, prop shaft, and skeg all in one, and would be simple to rig. My only concern is how a rather large fixed skeg so close to the rudder would affect directional stability in the turns. I know some boats use turn fins, but they're amidship or so...

Thanks in advance for your thoughts/ ridcule.

[Corpus Skipper]

Oh boy, here we go again. See this: http://boatdesign.net/forums/showthread.php?t=650

are there any simple F-N-R inline or L (or Z?) drive transmissions out there that are cheap and designed for said power output?

Borg Warner Velvet Drives can be had fairly cheap, and come in a variety of ratios. Don't know how you'd couple it to that engine though.

If I were to use an outdrive from a sterndrive, but have it fixed and attached to the bottom of the hull just fore of the stern, and have a movable rudder at the stern, how would that affect the handling of the boat?

I think the skeg would tend to override the rudder. But anyway, a stern drive has to be mounted at the transom to run right.

[Thunderhead19]

I never ridicule.

I'll tell ya, I was on a sea-trial of a 15' boat unlawfully re-powered to 225HP. At about 70mph things started to get scary. Ahh, to be young and stupid again!! Our 15 footers rate in at about 50HP, but I digress.

Cheap is a relative term, If you're new to boating, nothing is cheap. I don't even own a boat anymore. Making stuff from bodged together parts seems to be your forte' (you and me both). If you have lots of the parts from the chevy still, use the transmission too, and the CV joints (CV joints are wayyy cool)). You should be able to come up with a nice down angle through the hull bottom or even come through the transom and make your own trimmable surface drive. good luck.