Where to the Engines Go?

Discussion in 'Powerboats' started by big-boss, Nov 19, 2008.

  1. big-boss
    Joined: Mar 2008
    Posts: 58
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Exeter, CA

    big-boss Junior Member

    I am in the process of repowering a 27ft Uniflite Express. It had twin SB Chryslers- I do not know what it will have yet.
    Question is:
    I know after swinging on my crane where the CG is +/- couple of inches with no engines. Where is the optimum place to put the engine weight? Front or back of CG? Or on CG. I would think it would be advantages to put fuel tanks closer to CG and the engines as far back as can go? I really do not know- I am a car guy and that is what we like. Thanks
     
  2. KnottyBuoyz
    Joined: Jul 2006
    Posts: 829
    Likes: 55, Points: 0, Legacy Rep: 685
    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    Does it have straight shafts? V-Drive? Stern drives? Ideally you'll want to put them back where they were originally as the stringers where they were should strongest part for mounting engines. It's a planing hull so weight in the aft end isn't all that bad a thing. Trim tabs will correct for that.
     
  3. big-boss
    Joined: Mar 2008
    Posts: 58
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Exeter, CA

    big-boss Junior Member

    It is stright shaft drive. Had two 318's w/ velvet drives. I am either going back with one or two engines-don't know yet but I have a set of very cool Arneson ASD6's. I would like to put the engine back for more usable room. The stringers go all the way to the transome
     
  4. KnottyBuoyz
    Joined: Jul 2006
    Posts: 829
    Likes: 55, Points: 0, Legacy Rep: 685
    Location: Iroquois, Ontario

    KnottyBuoyz Provocateur & Raconteur

    So the engines were mid-ship in the boat to begin with. Can you post some pics I'm not familiar with that kind of boat. The Arenson's are surface drives aren't they? Lil' over the top for this kind of boat maybe but who cares eh?

    The 318's were tough engines, ya practically had to drown them to get them to quit!
     

  5. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 489, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You can move them aft and use a V drive arrangement, or you could go all the way aft and use stern drive(s). With the weight moved so dramatically, particularly with stern drives, you'll need to relocate tanks forward in the belly. Ultimately, you'll still need to launch and "trim" her up if she's doing something weird, like proposing. Tabs could be an option, but getting her to trim is a much better solution, which doesn't require additional systems, parts or installation and adjustment. Finding her LCG would have been much more useful if the original engines were still aboard. Can you install 1,700 to 1,800 pounds (approx. what twin 318's with Velvets weigh) of ballast on the engine beds and re-hoist her to find the real LCG?
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.