transom repair opinions

Discussion in 'Materials' started by swade, May 21, 2012.

  1. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    Ok well i suspected but i pulled a motor on a boat i've been cleaning up, got some rot around one of the bolts ..was able to dig a bit out around there.

    Bottom two bolts damp, not mushy or rotten can't stick a pick in it but it's slightly damp, top left a bit degraded but can't dig anything out, top right can definently dig around..maybe couple inches to one side of the bolt. I drilled a couple of small exploratory holes between top and bottom, shavings not too aweful.

    It could probably ride a bit longer there's no movement anywhere but it will need to be addressed.

    attached a pic of a boat like this one, you can see the somewhat triangular outboard well. It looks pretty darn doable and reachable The bottom of that box is solid glass as well as the sides..it's just that back piece that's wood.

    Stringers are good, i think water made it's way in at the top cap there and started from the top.

    I assume i can't just cut out the top well cap area dig/auger the rot out and rebond some ply from the top with clamps and epoxy? It's a pretty small transom area.

    Thanks for any advice.
     

    Attached Files:

  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Usually there's a lot more then you can find by exploring the holes. Rot will follow checks, grain lines, glue lines, etc. and generally the out of sight rot, is 10 times the visible stuff.

    There are products that suggest you can just pour it in and all will be well. I'm grateful for these products, as they've brought me a lot of work over the years. You see, it pours in all right, follows the path of least resistance, typically a void, eaten out grain line or what ever and immediately flows directly to the very bottom of the transom, where it pools into a neat pile and hardens. This is a fortunate thing, as all I have to do is smack it with a hammer a few times and it pops of the hull shell for easy removal as I rebuild the rest of the transom.
     
  3. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    Hi Par,

    Thanks for the input. Just exploring options here initially. It's roughly a 2x1 somewhat triangular piece, seems pretty small. So you have to cut it out from the back? there's no way to cut the top cap at the well, auger out, insert new ply with epoxy and clamp everything?
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You can remove the core from out side (the easy way) or the inside (the hard way) or from above (the really hard way) and each has good and bod points to consider.

    Removing a portion of the deck cap and gaining access through a 1.5" wide slot is problematic at best. Some use a chain saw, then shop vac out the chips, then go back with a flap wheel and extension to clean the interior surfaces. I don't trust this method, mostly because I can't see if the contact surfaces are clean and "toothed" well, for a new core bond. This method means you only have to bond the top of the transom back down, so is minimally invasive but tabbing is very difficult.

    Cutting off the outside skin is the easy way, as you have complete access to the core and it can be hacked out with one of several methods/tools. It's also easy to insert the new core, bond and tab things in, etc. Naturally you'll need to tab and bulk up removed hull laminate, on the transom's outer skin, but most boats that need a transom core also need a paint job any way, so it's my first choice usually.

    Cutting the deck cap and liner inside the splash well can be challenging. It's usually best to just remove the whole splash well, maybe hiding most of the cuts in lockers, bait well edges, etc. This technique preserves the external skin, though you will have some cosmetic repairs, on the liner and deck cap (often a single unit). Many find repairs to these areas more acceptable, than painting the transom, as you need to do with an external skin access job. Removing the core with the inside skin removed is a little less easy then if you remove the external skin, but a hell of a lot easier then trying to drop a chain saw down a 1.5" slot.

    In all cases the skins need to be clean and free of old core wood, then heavily scuffed with 40 to 80 grit, to insure a good bond for the new core. As to clamps and such, most repairs are unique, so some inventiveness on the part of the guy with the grinder is necessary. You can cut 2x4 braces and wedge these against potions of the interior, make up some clamps with threaded rod and long lengths of 2x4, maybe some well fed friends can stand there for a few hours (provided lots of beer) pushing against it. There are many ways to solve this problem. With 'glass boats anything can be cut away, ground down, repaired, added to, etc. and all put back together without anyone knowing you ever fooled with it. The cleverness of the repair person is the only hitch to this equation.
     
    1 person likes this.
  5. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    i can see how inside could require some forethought you have to make sure you can get your transom cut piece back there, i'll have to look it's not that large i could probably get it back there though wouldn't be fun...but could avoid cutting the well. I don't think i'd do this without cutting that, it's a darn tight fit back there.

    Top just seems so much easier to me since it's only 1 foot deep and 2 wide. That outboard transom jut out is surrounded by solid glass bottom and both sides, but I see what you're saying about the 1.5" and actually getting the old laminate scuffed and cleaned enough to bond.

    I'm comfortable cutting it out from the outside...and repairing the appearance, i've done some glass, gelcoat work on the boat (but it's just appearance type stuff) what i'm not sure about is how to cut the outside skin, and glass it back so it's structurally sound...
     
  6. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    I'll check back access tomorrow, i've been reading your help in threads on transom repairs and how far you want to grind back from the cut to get some tooth.

    With this jutting out like it does (ie not a flat back transom) it would seem i'd have to cut right before those 3 transom corners grind around the corners to tab everything in...but there's alot of transitions there, doesn't look as simple the the flat back examples others have done.

    If i can get reasonable good access from the back it may be easier.
     

    Attached Files:

  7. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    ok. Looked again. making a bit more sense now. i see i'm pretty ignorant but learning here. 2 stringers tie into the back glass at that outboard well jut out. Go in from the top i gotta do some major cutting out around the well, and there's still a good bit of work tieing things into together stringer wise when you go in that direction. Stringers are good, they're composite, why mess with something solid obviously providing most of the structural integrity.

    So i think go in from the outside, i'd rather spend time fairing, I assume that stringer back end is more structural than the front visual part?

    The only ply i see is on the face of that jut out, sides, bottom,etc the rest that i can see is all glass. I'm thinking cut a few inches in from all of corners of that jut out on the outboard flat side (see picture attached) ,clean everything up, grind back on the sides but not go around the curves...ie a bit back from the redline.

    Think that will give me enough to cut it out and grind back without getting into all of the complicated curve parts and still tie the cut piece back in? How far do you think i could come in from the edges? ie the red line.
     

    Attached Files:

  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    3" is about as tight as you should get, with 4" or 5" being better. The "flange" you leave, the easier the skin repair, from a structural stand point. Being flat, it's pretty easy to fair. The last thing you want to do is have to wrap tabbing around those corners, from a fairing perspective.
     
  9. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    Hi par,

    Yes that's what i was hoping, avoid curves corners and that flat would be easy.

    I spent a bit of time this morning making sure i knew where everything was. The top blue line is the wood , at first i was worried it might do a u shape there but where the red dots are there's no wood, so it's just straight across. I confirmed inside the well step outs it didn't go back there as well (luckily not!), green lines are stringers.

    Now i'm stumped. I'm not sure where to cut to connect my blue lines (top with the bottom) and avoid those step out curves..and still be able to wrangle the new stuff in...since there will be a 3"-5" lip all around. Maybe i just need to bite the bullet continue on up around the step outs and just deal with tabing around those 2 step outs inside corners..but i'd really love to avoid that.
     

    Attached Files:

  10. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    Here's what i'm thinking cut wise now

    Blue is the existing wood layout. Red is where i'll make my cuts (3-5 inches back) that keeps me off the step out corners. Only thing is i'm not 100% sure i'll be able to squeeze in a new piece. I'm sure i'll be able to clean everything.

    I'm hoping there will be enough play to slide it into my cut out slot from the top, if not, i'll have to figure out what to do next.
     

    Attached Files:

  11. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    I'm having a bit of a problem visualizing with the 3-5" lip all around how i'm going to get the new wood in there, am i going to need to cut the top cap lip and slide it in piece at a time past the 3-5" lip on the 2 sides?
     
  12. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    i think i got it, i'll cut about 6 inches or so up the cap sides at the lip, that should leave plenty of room to leverage it in at and angle.
     
  13. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    There's probably no way of avoiding cutting the flange on the deck cap/liner. You have to be able to drop in the new core. You're not going to lever in these pieces. You ultimately need enough room to get in there and fillet the ooze out and tab things in, so you need access. You're going to have quite a bit of "fixing" to do, another few feet of gaps to fair isn't going to be a deal breaker. Putty and paint will fix everything.
     
  14. swade
    Joined: Jun 2010
    Posts: 123
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: apollo beach,fl

    swade Senior Member

    Hi Par, thanks!

    Yes, i went ahead and cut that flange just awhile ago, i figured there was no way to avoid it, but better up there than tight in with the step outs...that's an easy cleanup job there. I see everything now! including where the transom back glass ties in with the stringers.

    Haven't cut the transom yet, going to ponder it some more over beer for a day. But yeah it's rotten and wet as heck as i guessed, needs to get done. Just blowing things off with my compressor air gun spit out wood.
     

  15. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Much of the core can be knocked off with a hammer, but a surprising amount will still be solid and a good tool is a power plane that you don't like so much. The core will probably have some staples so the blades will take a beating. I have a 3 Harbor Freight power planers, just for this purpose. They really suck at fine work, but they come with a spare set of blades and I just swap them out as I need to. They'll die fairly quickly (usually break a belt), but they're cheap so you don't feel bad when they do.

    The rest is hand work with an angle grinder and sanding disk. Use 16 or 24 grit, to make easy work of it. A flap wheel in the corners, hand chisels and some cussing are the rest of the tools. You'll figure it out and have extra beer on hand, as it makes things a little easier.
     
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.