1987 170 Rebuild

[wingnut]

In my 170 of similar vintage, they squirted foam into the gunwale to add flotation and hold the rod holder cutouts in place. This foam comes out between the hull/liner at the bottom and pools on the outboard side of the stringers, so it looks like you have the same situation. I did not remove my liner, but my guess is there is a LOT of adhesion between the liner and hull because of the foam. I can't imagine getting the liner out in one piece, but perhaps I'm wrong!

The putty on top of the stringers is normal, it's like a leveling pad so they didn't have to build to as close of tolerances (also sticks it down to some degree). They smeared it on and dropped the liner in before it cured, so that the stringer support height was touching the bottom of the sole. The putty planes or grinds off very easily if you need to remove it or adjust the height. If it is intact and you are not scooping out your stringers, I would just adjust the height down just enough to account for your extra deck thickness - my two cents.

[AquasportEd]

Wingnut, thanks for the reply. I havent checked the liner toward the bow platform, but the liner that remains in the picture running toward the transom seems like it will come off w/out much effort (famous last words...) If there isnt much concern of the hull warping due to its removal, Im going to attempt to get it out this weekend. Ive seen several other threads here where its been done, so heres to crossing my fingers.

Also, makes sense with what you stated regarding the foam atop the stringers. My plan from the start was to bring the deck all the way to the hull sides, and create a 3 piece hull with the cap being separate. I was going to run a "cleat" along the hull sides level with the top of the stringers to seat the deck upon. Then cut out most of the remaining liner and set it back in to act as a gunnel cap. I realize i will also have to fabricate some under gunnel supports to sturdy it all up.

Lastly, called my local supplier and ordered several sheets of 1in thick, 4x8' honeycomb panels to build the deck out of. Should have them in hand in a couple weeks. I still have a TON of more work to do, but with all these shipping delays I wanted to get the product sooner than later.

[AquasportEd]

More progress made this weekend. Removed the rub rail, and the fasteners holding the cap to the hull. Then went around the perimeter with a pry bar and broke it free from the hull. It broke free from the hull with out much drama, worst part was the number of screws holding the rub rail on, many of which had stripped heads. What did add some drama was getting the cap out of the hull. It was heavier than i anticipated, likely in the neighborhood of 300lbs. Took a little ingenuity, and removal of some pieces that i dont plan on using to complete the build. Anyway, next step looks like chiseling out the old foam and cleaning up the junk inside of the hull.

[Greenlake]

New here. I have a 170 but it doesnt have an access hatch for a coffin box gas tank. And the current gas tank is above floor under the helm.
Should i chase what isnt there or???

[RickK]

Welcome aboard Greenlake  The early center console models had the fuel tank inside the console - my '71 did.

[AquasportEd]

Not a ton of progress this weekend, but i was able to remove much of the foam from inside the hull, pretty much down to just glass now. The vast majority of the foam i removed was dry, and the stringers appear to be in solid condition upon initial inspection. I haven't stumbled upon any soft, or clearly delaminated sections yet. Though the wooden bulkheads toward the transom need replacing, but I'm responsible for some of their demise.  Been taking some measurements between the stringers and think I've found a gas tank online that will fit. I need to start planning on how to build back the section of stringer i removed to access the transom. But next weekend will likely be spent sanding the inside of the hull.

[AquasportEd]

Doesn't make for sexy progress pics, but spent several hours over the weekend with my grinder cleaning up the inside of the hull. Although I originally didn't want to, starting to realize I have to cut open the tops of the stringers to remove the old foam. Nothing seems wrong with their condition, but think that I've come too far to leave almost 40yr old foam sitting in there. So next weekend i plan on cutting open up the tops as neatly as i can, and removing the old foam. I also still need to build back the section of stringer i removed to cut out the transom. Thinking of building a "dam", then after pouring the new foam, removing it and glassing over it. Is 2lb density Polyurethane flotation foam the right call? Also what sort of glass (1708?) should i use when adding a layer inside the hull for around the tops of the stringers, keel etc? Thanks for any input




 

[RickK]

Got her nice and clean.   Good idea on getting the old foam out - piece of mind anyway.

[Fishhead]

looks good ed, i used a hole saw and punched a few holes on top ,got a prybar work from rear, break the foam up and push it out the back and work your way forward. saves glass work and aids filling stringers up with foam having more holes to dump in.

[AquasportEd]

I like that idea Fish and may give it a shot. Im thinking its going to be a pain digging that foam out w/ a pry bar, but ill be needing to drill those holes on top to fill the foam anyways so Ill likely give it a shot.

[AquasportEd]

So I started taking some measurements the other day and ran into an issue, hoping someone may have experience and can shed a little light...

Hope to be at the point in the next couple weeks where im finishing off the stringers and adding probably an 1in to their overall height to raise the deck slightly. So i started putting a level on my stringers and noticed i can never seem to get it level on the trailer. Ive adjusted the front jack on the trailer, added some height under one wheel etc, and i notice when i get the aft end of the stingers level, the front is then out and visa versa (almost seems as though the deck slopes down toward the bow). Sort of came to the realization that the boat likely doesnt sit level on the trailer (could be by design, could be the way the bunks are adjusted etc). Then i started thinking, how do i account for how the boat will sit in the water once a 300lb motor is hanging off the transom? I may be really overthinking this and getting caught up in the details. Ideally, Id think i want the deck to be slightly higher toward the bow to help with shedding water toward the transom scuppers. If anyone has experience with this Im all ears, thanks again.

[BradC]

I cut off 8” pieces off the top every 3’ or so, made it easier to hack out the foam and retop the holes with glass without worrying about keeping square and hull twisting etc

[AquasportEd]

Welp, good news/bad news on the project. Spent Sat morning removing the old leveling foam off the top of the stringers, then took a grinder to them and cleaned up the tops of the stringers. They look nice now. Started to pry out the foam and thats when i heard an odd noise...turns out the old cedar tree right next to the boat is in terrible shape and about to fall. Its in such bad shape Im shocked it didnt come down during a winter storm, it surely would have went right through the hull. So i had to put all the tools away, hitch up the truck to the trailer and get the boat away from danger. So progress on the boat has come to a halt until the tree get removed. Though i did make an executive decision and ordered my gas tank today, 25gal poly for below deck.

[AquasportEd]

Quick update, took some of the advice here and pryed the foam through access holes. I didnt cut these holes, they were from the factory, most likely where they originally poured the foam. Still some foam i have to remove, but got about 75% of it all out. Overall it was in pretty good shape, stbd side was worse than port, but still not terribly wet. Gas tank also came in, going to have to start dry fitting and figuring out exactly where to run conduit for the outboard controls, etc. Any recommendation on diameter for my rigging tube to the transom? Thinking in the neighborhood of 3in.

[RickK]

Looks good Ed. If you plan any bends in the rigging tube(s) 3" should be enough at the bend - you have to test pushing the throttle and shift cables through the bends You can use smaller on the straight portions. I planned 2 tubes.


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