Should I recore my transom?

[jbrinch88]

1985 24' offshore with open transom. I'm currently in the middle of restoring it (check photo section) and I'm wondering if I should recore the transom while the boat is completely apart. I've already done the floor hatches and wasn't planning on going any further than that really (structurally) speaking. However I'd hate to have the boat all finished and within a year or two have to rip it apart again. Not worried about the work involved, but I know that it may open up a can of worms and I really wasn't looking to rebuild stringers or anything like that.

The floors and deck on the boat are solid and I haven't noticed any real flex in anything besides the floor hatches which I already took care of. The wood support where the cockpit lights go were wet and rotted so I am planning on replacing that. Would be fine without it but I'm doing all that I can to keep the integrity of the boat. Only test I did on the transom was put a 4' pipe wrench on it and jumped up and down on it and didn't see any movement at all. Any tests I can do to really find out the condition of the inner transom core without drilling a bunch of holes in it?

Thanks!
Jason

 

[DennisG01]

Well, "opening up a can of worms" is the $64,000 question, isn't it? How comfortable are you in your diagnosis skills of checking for delamination and rotten wood? Do you have a marina or a surveyor in the area that can do this (along with a moisture reading)? Another thing you can do... anything that's currently screwed onto the transom (transducers, trim tabs, etc) is probably due to re-sealed, anyways. Pull them out, check the wood. Do you still have the garboard drain plug that uses a rubber stopper? I hate those on bigger boats - it's OK on a Jon boat. I drilled mine out and rebuilt the area and then installed a real, bronze (screw-in) plug. If you do that, that would give you a real good look at the wood in the lower transom.

The "leverage" test is fine, but it's not the "be all, end all" of tests. It's one test that can be used, along with others, to diagnose transom health.

 

[suzukidave]

you can drill as many test holes as you like in the transom from the inside of the bilge and inspect the shavings that come out. just don't go right through (you can feel when you hit exterior gelcoat) and refill with epoxy.

 

[jbrinch88]

Dennis, I'm actually a full time employee at a marina on Long Island haha. Been in the business for almost 6 years now and there is still PLENTY I have to learn. I started working under my fathers wing and now mostly do all the service work, welding, equipment operating, elec. installs, and custom fab work but NO fiberglass work to speak of. The work I've done on this boat is really all the experience Ive had with glasswork.

We have a great glass guy that works here as well and Im constantly picking his brain for advice, just thought I'd throw it out on the interwebs to see if there were any tricks. I'm going to at least drill some holes with a small hole saw just through the glass, pop out the glass skin and take a pick or screwdriver to the wooden core and see how it feels/looks. If you look at my thread you'll see the boat is completely gutted and I've already checked the engine mounting holes and drain plug fitting hole with pick and the wood seemed decent still.

 

[DennisG01]

That's alright, I've been in the business for over 1/4 century and am still learning! I understand where you're at (mentally) - this past winter I ripped the ENTIRE floor out of my Offshore, part of the aft stringers and the entire aft bulkhead. Rebuilt it all, better than it was from the factory, new floor (all wood encased in multiple layers of epoxy BEFORE laying it in), etc, etc. I was at least smart enough to carefully "skin" the cockpit fiberglass floor off so I could reuse that and not have to lay down a completely new fiberglass floor (although I did add one layer of mat).

What the link to your rebuild post? Sounds interesting - I'd like to take a look.

"Picked some holes"... you picked some upper holes and the lowest one - good. It's sounding reassuring that everything's alright. Before you drill some holes, though, I'd pull the tabs and/or 'ducer's off. They really should be resealed every 10-15 years, anyways.

If you want to do a little project, drill out each screw hole twice as big as the screw. Mix up some thinned epoxy (or heat the transom and the epoxy - which I prefer) and paint the wood with that mixture a few times (before it completely dries). It'll wick into the surrounding wood. A pipe-cleaner works great for this. Then, tape one side of the hole (tape the inside - it's easier to work on the outside) and mix up some thickened epoxy, insert, and tape the other side of the hole. Or, with thick enough epoxy, you won't have to tape the outside. But sometimes that thinned epoxy dilutes the thickened stuff a bit.

Another way is to drill a small hole (1/8"), at a downward angle, from slightly above the hole. Tape both sides and use a syringe to insert epoxy that way. Either way, now when you put the screws back in, they're going into 100% epoxy. IF they should ever leak, the wood is completely protected.

Another tip... whether you do the epoxy thing, or not, before you insert the screw again, counter sink the hole slightly. This is good for preventing spider cracking, but also to give a larger area for sealant to sit.

And... you probably know this, but... don't use 3M5200 for any of the screws or for ANY "normal" sealing. 5200 has more tensile strength than the bond that exists between the gelcoat and the glass. Which means if/when you need to remove something... in addition to it being a royal PIA, you stand a good chance of ripping gelcoat off.

 

[jbrinch88]

viewtopic.php?f=7&t=21373

 

[DennisG01]

I didn't read every post, but I looked quickly at most of it. I'll definitely go back and look at it some more. You're doing some really nice work, Jason. There's no better way to learn than to completely immerse yourself in the work - which it looks like you are DEFINITELY doing! Nice work.

Tip for working outdoors... I had an extra long hardtop to work with (which helped), but I added a wooden frame at the stern - basically a 2x4 going straight up from each stern cleat, then sandwiched those two pieces with two boards running port-starboard. Then a "ridge" board running from that upside-down "U" shape to the hardtop (which could be more lumber, instead). Well, you've probably done enough wrapping to know what I'm getting at. Basically, I had a squared-off stern end. I added a couple 4' shop lights inside, along with an oil-filled "radiator" style electric heater and a nice big zipper door... even in the dead of winter it was surprisingly comfy in there!!! Whenever someone came to the house and asked where I was, my wife would just say - he's probably in the big, blue bubble on the side of the house (didn't have white shrink that was wide enough at the time!)

 

[jbrinch88]

Thank you, I'm really trying to not cut any corners with this boat and do everything the way I want and just deal with however long it takes. I have my 22 seafarer that hasn't sold yet so I may not be completely "boatless" this summer.

I do regret not wrapping the boat after seeing 6+ inches of frozen ice in the bilge and cockpit however I think it would have made sanding/fairing the boat more uncomfortable. For awhile I was putting it in the shop whenever I worked on it but now the shop currently has a 40' down Easter and a 45' wellcraft scarab crammed in it both getting new paint.


I probably won't get back into the glasswork until the end of March when the weather breaks. For now I'm trying to work on getting some things done that I can put in once the boat is painted.

 

[VeroWing]

I did a rebuild on a 22' Grady Seafarer transom a number of years ago. There are different ways to do a transom recore: from inside/from outside/from top/wood/composite/pourable/etc. I did mine from inside so as not to disturb integrity of exterior fiberglass. I did not trust my fiberglass skills enough at that time to do it from outside. It was quite a bit of work, and pretty involved. I honestly think if I had to do it again I would open top of transom, gut out core, dry thoroughly, and use a pourable product. I did long and thorough research on this method and could not find one single first hand case of this method failing. Plenty of hearsay though!

If you remove a lower transducer/speedometer pickup and have water come out of screwholes then your transom is wet. Doesn't mean core is completely shot though. As suggested earlier, you can drill holes (1/8") in transom and check shavings in various areas to determine core quality. If most of core turns out to be solid, you can actually locate and cutout bad sections and replace with new wood, etc & fiberglass/epoxy paste. If properly done, epoxied area will be stronger than original core.

Hopefully, your transom core will check out to be solid and not need replacing. Good luck.

 

[DennisG01]

I think it would have made sanding/fairing the boat more uncomfortable.

Yeah, you got that right! That part was a real PIA. I put a large box fan in the shrink door to help evacuate, but it was still all over. I went through a lot of masks.

 

[suzukidave]

looking at those photos in your other thread you have a huge motorwell slot to work with. i think you can dry it out without having to cut away the outside of the transom.

what i suggest is you get a couple of 3/8" lineman's extra long drill bits and drill holes every 8" straight down from the top of the transom being careful to stop at least 5" from the bottom. in between those holes drill another set of holes half way between the previous depth and the top of the transom. if you are really keen you can also add some holes at quarter depth.

i would also drill some 60ish degree holes into the vertical walls of the transom slot. i would then drill a series of horizontal holes halfway into the thickness of the transom from as low as you can from inside the bilge. these are for air intake.

then i would suck air through your top holes using a shop vac to dry it out.

to do this go to your local irrigation supplier and get some plastic 3/8" id irrigation "header hose" and some plastic end nipples and fittings and pvc pipe to make a distribution manifold with enough holes for every transom slot hole. also take your shop vac hose with you. what you want are the step up fittings to connect the manifold to the shop vac with minimal duct tape.

turn the shop vac on for 48 hours to suck moisture out of the transom through this rig. you do this in warm weather or under cover with a space heater in the bilge for a couple of days before using the shop vac.

then you fill all your vertical holes with epoxy resin with virtually no catylizer. you want it to soak into the wood before it sets and ideally after a couple of days all the holes are dry. if the epoxy disburses keep adding more until it does not soak any longer (keep an eye open in your bilge for leakage) then remove the last batch of epoxy from the hole. i recommend rot doctor for this. if the epoxy does not disburse at all in a hole then that part of the transom is waterlogged.

assuming you get decent penetration, i would then fill all the holes with a quicker setting epoxy and call it good.

for areas where you do not get good epoxy penetration you may want to do some exploratory drilling.

 

[gw204]

I'm really trying to not cut any corners with this boat and do everything the way I want and just deal with however long it takes.

That's your answer right there. Open it up and do it right. If you are rebuilding this boat for the long haul, the additional work of putting in an entirely new core will be worth it.

 

[jbrinch88]

I'm really trying to not cut any corners with this boat and do everything the way I want and just deal with however long it takes.

That's your answer right there. Open it up and do it right. If you are rebuilding this boat for the long haul, the additional work of putting in an entirely new core will be worth it.

This is true to an extent. You have to stop somewhere, I could seperate the top and bottom of the boat, rip out the floors and replace the stringers, and replace the transom. It comes to a point where what is your time worth? At that point I'd rather spend the extra coin on the same size boat but newer. I would like to be using the boat by summer 16'. At least that's what I'm shooting for now.

Guess that makes me a hypocrite, but if my transom is in decent shape ( haven't had time to really look at it thoroughly) I will leave it and replace it when the time comes.

 

[jbrinch88]

I think it would have made sanding/fairing the boat more uncomfortable.

Yeah, you got that right! That part was a real PIA. I put a large box fan in the shrink door to help evacuate, but it was still all over. I went through a lot of masks.

Exactly. Once the boat is fully painted, Im going to shrink wrap it but build a big enough frame so I can stand up and work comfortable etc. This way the weather will not stop me from rigging the boat next winter.

 

[DennisG01]

I think it would have made sanding/fairing the boat more uncomfortable.

Yeah, you got that right! That part was a real PIA. I put a large box fan in the shrink door to help evacuate, but it was still all over. I went through a lot of masks.

Exactly. Once the boat is fully painted, Im going to shrink wrap it but build a big enough frame so I can stand up and work comfortable etc. This way the weather will not stop me from rigging the boat next winter.

You know, in regards to whether or not to re-core: I agree with the sentiment of "if it's good enough, leave it alone for now". However... considering how far you have the boat ripped apart right now; that there's no engine on it; especially that you're planing on painting... it would be SO easy to skin the outside of the transom (leave about 1" around the perimeter), replace the core and epoxy the skin back on. Since you're painting, it makes it even easier since you don't have to worry about re-gelcoating the seam. Just feather the seam, smooth it and you're good to go.

If you do decide to do this... I saw in your build thread where you talked about coating the plywood before putting it into the floor hatch. That's good, but you can take it one step further (and maybe you did this, just didn't mention it): The wood should really get about 3 or 4 wet coats of epoxy. Brush/roll the first coat on, then come back in about 5 - 10 minutes and you'll notice that the epoxy has soaked into the wood and is no longer laying on top. That could very easily lead to a poor bond between the wood and the subsequent glass. What you do is after the epoxy has soaked in (you'll be able to tell since the wood won't be shiny anymore), throw another coat on. Check again in another 10 - 20 minutes. It'll usually take about 3 or 4 times. Then you can start your glassing. You'll end up with a MUCH stronger bond this way and the wood will have been more thoroughly saturated.

Some tools I found to make my work easier when getting the old wood out:
-- An oscillating tool with the "scraper" blade
-- Of all things, I found a shingle removal tool was a huge help since it is basically a blunt chisel, but has a lot of weight/mass behind it

 

[Bruce123]

yeah, i agree with you veronica. i also like that answer.