1987 170 transom/deck rebuild

[Doherty8]

  I picked up a 1987 Aquasport 170 a couple weeks ago with no motor on, knowing it had two minor soft spots next to the seat. After further inspection noticed if I stuck a stick into the lower left outboard mounting hole I could build a garden with the mulch coming out. It felt solid otherwise and passed the hammer-rebound-and-sound test, so after a lot of self-debating whether or not to slap a motor on it and left it rip for awhile I've decided to get into "a little rebuild."

  My initial plan after reading plenty of forums and asking some people was to take the transom out from the top and do a seacast pour. Also maybe trying to inject the deck to firm the spots a little bit, I wasn't too worried about soft spots knowing that it 99% means rot but also knowing that a lot of times it's just the deck and doesn't make your hull explode upon impact with a wave.

  Long story short I have the boat wide open now with a full fledged deck/transom rebuild ahead of me. It kind of just happened the further I dug into it.

  I was going to wait until I finished to post all of the pictures so that if anyone else had a 1987 170 and they wanted an idea of what it looked like tore apart in pictures then they could have a reference point, but figured if I post some updates now then I'll have a lot of useful help from the pros. Hopefully I check it often enough to heed your advice (or warnings) before I dive in and do certain parts of the project, but for now here's some pictures because I know that's what the people come for. Sorry in advance if I don't reply quickly to responses.










This is where I attempted the transom rebuild from the top












I noticed the wood was A LOT better than I had anticipated from that one motor mount hole, and knowing I wanted to look under the deck anyways I decided to go with a traditional transom rebuild and remove the inner skin.













And then onto taking some of the stringers out to get to the full transom. I still don't plan on redoing the stringers anymore than retabbing a little bit maybe, but they definitely have some water in them.











Onto the console/t-top removal and then the entire deck after seeing how wet the wood was, knowing that heavy stuff as well as the waterlogged foam had to go. The weird thing was that the foam just in front of the bilge area and behind the fuel tank was completely bone dry.











The area just ahead of the fuel tank was holding water because the pvc tubes flowing under it had about $5 worth of old coins/screws/nuts/debris sitting in and around it. Snaked the junk out and shop-vacced it.











Any tips would be appreciated, posting this morning also allowed me to procrastinate a little bit from starting more work on the boat. Most of the stuff directly ahead is getting the rest of the wood off of the transom and a lot of grinding up a lot of the fiberglass.

[RickK]

The coins usually come from people putting stuff in the anchor locker up front.
When you are tieing in the transom core you want the best mechanical attachment to hull sides and hull bottom. Usually you need room to work and that is usually 18" of clean glass from the inside of the transom. The typical lamination schedule is 2-3 layers of 1708 cloth on the inside of the ground down/clean transom fiberglass, then lay the core in, which is usually 2 layers of 3/4" marine ply or some composite to about 1.75" and then lay in 3 layers of 1708 cloth on the inside of the core.  The lamination overlaps are typically 3",6",9" or 4,8,12. By the time you're finished you will have laid in glass out to about 18" from the transom glass. That being said, you may need to cut out more of the liner on the sides to be able to work.
The center drain hole in the bottom of the transom is, at this time, the low point in the hull, thus allowing everything to drain out the garboard plug. As you add all the laminations of glass and the core, you are moving the low point forward and it will end up about a foot forward of the transom. Here are some threads to explain how to combat this. Many members have followed the instruction and been fine. I only wish I had thought of the problem before I did my rebuild.  I now have an inch or more of water in the aft of the boat.
Here is a link to where I explain the thought of the PVC pipe:
http://classicaquasport.com/smf/index.php?topic=13148.msg133124#msg133124

Here is a link to where I show what is actual problem
http://classicaquasport.com/smf/index.php?topic=13148.msg133556#msg133556

Here is a link to Hawgleg's rebuild that shows the PVC pipe installation to keep a drain at the new low point of the boat
http://classicaquasport.com/smf/index.php?topic=13148.msg134262#msg134262

[larsli68]

Brings back memories!

Keep up the good work. 

//Lars

[wingnut]

It's interesting to see the subtle differences in materials and construction just one year makes.

I think you made the right call on the transom removal. I poured mine, but was really saved by the fact that it was almost entirely rotten inside. I think it would have been VERY difficult to get all of the material out being mostly solid like yours.

[larsli68]

1/3 of my transom was not rotten, and took 90% of the work to remove... I poured mine too, but would have done what you are doing, had I known how much work it was to remove it from the top.

//Lars

[Doherty8]

Lars and Wingnut, funny enough your post's were the main two I looked at for reference points, wish I could have went through with the pour-able route.

Question for any pros before I get too far, I've grinded all the wood off the transom and grinded down the bottom and sides of the hull. Do I need to go 100% down to the inner hull skin if I'm hitting good glass and roughing it up? I'm assuming this is a thicker area from the factory lay up but I don't want to grind too far if it's unnecessary. If it makes a difference in terms of mechanical bonding I will be using epoxy.

Pictures of the transom/hull bottom at the drain plug area.

[RickK]

Looks like you're ready. Don't forget to add the pipe before you start glassing.

[wingnut]

What kind of core are you putting back down? I think the biggest thing is whether the inner surface is pretty smooth. You want your core to lay as flat as possible and be fully adhered without big resin pockets.

Pourable is great in some applications but I’m sure yours will be great too, you’re off to a good start!

[Tampa Bay Mike]

It looks good to me. As long as you have all the wood out and you've made it to clean glass you are good 👍

[larsli68]

Yes, looks great. Plenty of acetone wash before you start fiberglassing.
But you know that already.

Great work!

//Lars

[Doherty8]

Been doing little things here and there, the planning and thinking of what to do next seems to take the most time. Since last post I've ordered most if not all of the supplies I should need, I've got photos to show of some progress and mistake/fix up. Also have two questions at the bottom of this post after the photos if you guys could be of any help, thanks.



Glued together with epoxy glue



The 12" throat clamps were from harbor freight and worked great for this style boat. I also used top clamps and for the middle areas a bolt through the scupper holes with 2x4's on the other side. Note to self get a long enough bolt to use a 2x4 on the outside as well so it will get better pressure along the whole width.







I ended up epoxy gluing the old drain plug fitting to the pvc pipe trying to keep it at the correct angle for drainage. It looks nicer having that and the screw plug seemed easier to keep for me then fitting the hole for a new plug. When I installed it I made sure the drilled hole was bigger than the pipe and I tried to take care to seal up the hole with epoxy glue so it wouldn't get water.



And here's where I think I messed up. When I got to the tabbing I used thickened epoxy to make a fillet, while it was still wet I used 6" tape then 12" tape all wet on wet. I feel like I used a lot of epoxy to soak it up but the end result did not look good to me.



I grinded most all of it down to nothing again



This is the re-do I did today and I used what I feel like was A LOT of epoxy to fully soak it in, trying to roll out bubbles without pulling the cloth from the corners and making air pocket there. I feel a lot better about this tabbing, only did one layer of 8" this time.




So the question is was that first attempt at glassing in the tabbing enough or was I right to have removed it and redo it? If so then is there a better way to wet out 1708 so I get it transparent without using a load of epoxy, it seemed like some spots stayed white even though I drowned it with epoxy and rolled any air out. Trying to get it figured out before I lay on the big sheets of glass and risk messing up a big area.

Also a little off topic from glassing but when I put the floor in should I keep the cable-dugout on the side and just cut the wood to conform around it or remove it and use new 3" pvc piping to route all wires/cables?

[RickK]

Guessing on how much epoxy is going to be needed can waste a lot (don't ask how I know that). Someone showed me the way to get a close estimate - weigh the cloth on a postage scale. In the pic below The 1708 weighed 49oz. I added some extra weight to cover the scrim on the plascore plus some other things I was laminating. Take the total and divide by 3 - 1708 soaks up about 2-3 oz of resin per yard. So figure 3.  So in this case I calc'd 18.6 oz of resin, which was just enough to soak the cloth adequately.




Yeah, waiting for the fillets to harden a little is a test of patience - most people fail this the first time. The tape was really not needed on the transom but didn't hurt anything. You could laminate and tab all at the same time.
As for your lamination, how many layers of 1708 are you going to use on the inside of the transom? Typical is 3 layers overlapping with 3, 6, 9" or 4,8,12" The dry cut of the 1708 you did  in the 5th pic looks good and you can see the built in tabbing caused by the cloth going out on sides and hull bottom. Just add 2 more layers, dry cut with a couple more inches of overlay on each.

[umecheme]

Did you do a layer of epoxy on the plywood first (no glass)?  I made that mistake.  The plywood kept wicking the epoxy out of the mat, and it wouldn't wet out. Ended up ripping it off and redoing it.

[RickK]

I roll epoxy on the wood and then flip the cloth into the freshly rolled area, use a hard roller to roll out any air, add more epoxy on top, flip the next layer onto the new epoxy and repeat until all three layers are rolled into the resin.
Some people do a coat on the wood and let it harden.  Then you have to lightly scruff it back up before proceeding.

[Doherty8]

Rickk - I plan on using the tabbing to get some strength started then 2 more full layers over everything with the final layer being approx. 9" out

Umecheme - I put a pretty thick layer of epoxy on the plywood first then layed the 1708 mat side down in it then rolled out epoxy over it to soak everything and run air out

I used about 1 full quart bucket seen on the bottom right of the last picture for this tabbing. I can't imagine how much I'll use for the entire sheet at this rate