Seaswirl Tempo 17 sole, mounts, stringers?

Discussion in 'Fiberglass and Composite Boat Building' started by ster1, Apr 30, 2013.

  1. tunnels

    tunnels Previous Member

    45 mm is not that thick and the size of the wood thats required is only quite small and by the time the cut out has been done there not a lot left so heavy !! dont think so . the older stern drives didnt have the motor hanging off the transon like the newer ones do .:confused:
     
  2. ster1
    Joined: Aug 2012
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    Location: colorado

    ster1 Junior Member

    https://picasaweb.google.com/gillyn...authkey=Gv1sRgCJDF3MWy3fLupgE&feat=directlink

    Here is a link to some pics I just uploaded to pisasa. We got a little snow last night and it hasn't all melted but I'm pretty sure I don't have anything else to rot :) Pretty self - explanatory. I edited 2 of them; one I outlined in red the "gap" between the transom and the outer boards (whatever they are called). The Gap goes all the way around. I would say it's about an inch. I also drew a fantastically detailed shot of what I would think some gussets would look like. The point of the gussets would be to make the transom strong enough for a Mercruiser alpha 1 gen 1. Also shown are a few pics of the floor, which is more or less moot at this point. Not to say I won't re-do the sole, just it's not my biggest concern any more. I'm still wishy washy about whether I want to do all this work on this boat. I mean, I don't have an undying love for it. It's been a good boat, and certainly a practical one. It has served my needs fairly well. I want to do more stuff to it (who doesn't?) but it doesn't wow me. It fine. That's like saying your wife / girlfriend has a nice personality. Who wants that? We want our wives / girlfriends to be angels in the bedroom, whores in the kitchen and hotter than a 2 dollar pistol. Right? Gah. I can't get to a place that makes sense to me. I need to think about this; it's frustrating!
     
  3. tunnels

    tunnels Previous Member

    Its your choice !!

    The ply that was down the side of the stringer and the engine mount blocks could simply be replaces and the same layout as was there before not a problem just make a better job than was there before !!,same with the transom center piece, Just dig it off grind sand and prepair the surface to be glassed and fit ply the same thickness that was there before !! even in its bad state it was still working !! the transom side panels just rip the glass off the top which you already have started to do!!, fix the holes and reglass the side panels first off and completely seal completely separate to the center panel !!
    Laminate a centre panel same thickness as what was there and glass under clamp and then glass over the top with smoe good glass out onto the side panels . Gussets or knees will stiffen the whole thing but the hollow side stringers will need to have a good sand and scuff so new glass bonds really good !! Simple just redo what was there before and dont change anything from the origanal lay out !! mounts the same just add lots glass like what it had then refit all the mechanics and your done !! resin seall the underside of all your ply panels its last for a few years so will get a few years more .BUT if you going to replace and fit newer stern drive and motor then you have to think a little more seriously !!
     
  4. ster1
    Joined: Aug 2012
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    Location: colorado

    ster1 Junior Member

    I believe it can be repaired, and I'm fairly certain I can do it. I just wish I started last fall :(. Poking around on Frisco Jays site and gabbing on his recent restoration thread, I learned something about Mercs I never knew, and that was how the engine was mounted to the inside of the transom, as well as the stringers (I never knew it was mounted to the transom, I always thought it was just mounted to the stringers and more or less "floated" somehow), and acts as a stressed member, negating the need for more gussets, and also fully enabling me to put in an Alpha 1 or one of those SEI units. I can also gain a few more inches of room on deck with a Merc with a few minor modifications. With a modern drive, this project is looking more and more feasible.
     
  5. ster1
    Joined: Aug 2012
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    Location: colorado

    ster1 Junior Member

    I just thought of something; I'm sure it's a result of not knowing shinola about Mercs. If I mount my engine to the stringers, the crankshaft will be more or less parallel with them. My transom does not sit at a 90 degrees to the stringers, it's closer to 105 degrees. Does that mean my engine would have to be tilted up 15 degrees or is there something in the Merc mount that accommodates for this?
     
  6. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

  7. tunnels

    tunnels Previous Member

    Ok i have seen some people raising the eye when i mentioned 40 Plus mm thick transom for a stern drive !
    Lets get real here for a moment ! where is all the stress ,strain, twist ,push and pull taken with a stern drive unit ?? Is it taken on the motor and the mountings etc etc what about the brackets inside and out of a stern drive!!! whats clamped and through bolted between them ??
    You would put all and everything onto a 12 mm thick transom ??
    No thank you!!! over build, never under build !! You need to think a little about what you doing!!
    It reall dosent hurt that much !!
     
  8. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    Tunnels, you are right. Actually your transom thickness spec might be a little on the light side. When he reads the manual he'll see that Merc specifies a transom thickness of 2 to 2 1/4". The caveat is that this spec applies to the transom in an area 8" to either side of the vertical center line. The entire transom need not be so thick, you can taper it down. I visualize a thick center section tapering down to 1/2" or 3/4" as you get beyond that 16" wide center section.

    Regards,

    MIA
     
  9. RufNutt
    Joined: Jan 2013
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    Location: East

    RufNutt Junior Member

    In my boat the transom is built into 3 sections of plywood .The piece for the sterndrive area is 24 inches wide ( 2 pieces of 3/4 inch plywood laminated together then the keyhole cut out). Then there is 5 inches space of bare hull on each side( 1/2 thick of laminate and chopstrand) then there is another piece (1 Piece of 3/4 inch plywood)from there to the edge of the hull. At the keyhole it is 2 inches thick and use 2 pieces of plywood there to get the thickness needed to hold the sterdrive.

    [​IMG]
     
    1 person likes this.
  10. tunnels

    tunnels Previous Member

    yip thickness is needed and done in plywood ! the key hole is a pretty big hole to cut out and the clamping takes place over a pretty big area!! The ply on the 2 outer areas can be HD foam !!! it doesnt have to be plywood ! but should be around 15mm to 18mm thick to make the transom ridged, the gap left between needs(can be up to 50mm wide ) to be substantually glassed from bothsides so all glass is doubled there ,the foam side and the ply side so if you glass the panels independant of each other the all the glass gets doubles in those areas!! The ply ends up taking all the stresses in all directions The foam is to stiffen and brace the outer panels !!, i Have built dozens of production boats using just this method be it a stern drive or have out boards strapped on the back ! bolted to the transom of !!bracketed
    I am also in great favor of shapped transom !!simply the shape used increases the ridged strength noticeably !!
    The transom is a really important part of the boat it need to be super strong ,it takes all the torque and power of what ever drive you are using and if you under build then you are a fool to yourself and a danger to be around !! :eek:
     
  11. tunnels

    tunnels Previous Member

    The inside stern drive bracket has a pair of feet and mounts and totally supports and the rear of the motor and all its gizmos so if your stringers are to wide apart you could modify the engine mount brackets or fit a cross beam from stringer to stringer with a HD pad to mount the front of the motor onto .What ever you do its a much better way !!Look closely you will also notice the key hole is much smaller than what you had before . so like I been going on about need 40mm plus thickness is much better .
    Take your time and think about everything you want to do ! when all is clear !! just get on with it and do it !!:):p:D

    If I had my old laptop up and going I have a ton of pictures of transoms in various stages but not possible for a while till it comes back from being services ! I always photo recorded all and everything that we did to each boat if it was the slightest bit different and out of the ordinary !!
     
  12. ster1
    Joined: Aug 2012
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    Location: colorado

    ster1 Junior Member

    Thank you MIA for that link! That did answer my questions. I found an old Larson tri-hull on Craigs for less than a grand. It has the 160 HP I6 and an alpha 1 gen 1. I'm going to try to pick up that rat raft today (I'll post some pics of that ugly pig) and gut it. It even has a nicer trailer than mine. I'm still looking at a summer without a boat but I'm excited about the potential. I can spend the summer repairing my transom and floor, and take my time, spend the winter rebuilding the I6 and the drive, and next spring, I'll have almost a new boat (plus a few more ponies). I like it :)
     
  13. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    You're welcome. I'll bet that just about all of the regulars around here have spent at least one summer without their boat. Some of us have spent many years in the yard. It's worth the effort though, if you get satisfaction from building and/or designing your own craft.

    MIA
     
  14. ster1
    Joined: Aug 2012
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    Location: colorado

    ster1 Junior Member

    And thank you tunnels for all your help too. Cheers!
     

  15. tunnels

    tunnels Previous Member

    We are always here to help !!

    so when you make up you mind what you going to do then lets get back together again and sort the glassing details outside and inside and if you adding a new power unit more horses and a more up to date stern drive then those things need to be taken into consideration as well !!
    Cheers !!:D:p:p:)
     
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