1980 JC31 Flybridge Refit

Discussion in 'Downeast Projects and Boat Building' started by SlowLoris, Nov 28, 2018.

  1. SlowLoris

    SlowLoris Member

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    After a lengthy search, I found what I was looking for. With some broker games and a buyer backing out, I purchased a 1980 JC31 in Fall River, MA (not a fan of brokers but this one was pretty good for the most part). The boat had a full refit done some time ago but was pretty neglected after the first few years of use (according to the broker) and had been sitting for at least 3. The interior and exterior were in pretty good condition but clearly hadn't been touched since it was winterized last. The engine passed (6LYA-STP) with a tech and the sea trial went fine. The ride back to Newport was flawless.

    The stringers were on the soft side and I knew they would need to be replaced before the purchase, additionally there was some questionable boat building practices with the deck support construction but nothing that would compromise using the boat for the rest of the season.

    My plan was to put as many hours on the boat as I could until early November to get confidence in the boat, develop a good work list and then jump into projects. After 70hrs of running (lots of fishing, trips to Block and Montauk), I hauled the boat and got to work. My general impression is that the boat is a tank. I put it through some pretty gnarly stuff in Montauk and was thoroughly impressed. Following sea wasn’t an issue, just gotta proactive on the helm.

    Here is the list. Feel free to post any input, ideas or methods you have, always welcome second opinions. Over the past week I’ve removed all deck structure and am getting close to laminating the stb stringer. I cut the deck in 4, 3’ wide sections so I can remove them and use again (after de-coring edges).

    - Remove all decking/structure/stringers
    - Replace starboard and port stringers with penske
    - Replace deck structure
    - Remove fuel tanks, move sending units to the middle, manual sight hole, fuel transfer pipe, coal tar epoxy coat (Luthers)
    - Remove all wood bulkheads aft of helm bulkhead and replace with composite materials
    - Install surge tube on exhaust
    - Decore all thru deck fittings
    - Re-bed rudder post housing
    - Clean up or replace wiring, fuel lines, battery cables
    - Re-install deck/nonskid
    - Build third helm station with electra-dyne pot hauler (need help how to run hydro line’s for 3rd station)
    - Remove, de-core reinstall swim platform
    - Sandblast and barrier coat bottom (if I have time)
    - Update electronics
    - Build central tackle station w/ ice or livewell storage
     

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    Last edited: Nov 28, 2018
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  2. SlowLoris

    SlowLoris Member

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    Some more shots and demo. The stringers are 2x6's with 2 layers of heavy gauge cloth. they rotted as the edges were not laminated, various screws used to hold the deck structure to the stringers, one section of 2" stb stringer removed and a few large holes were cut and not sealed.
     

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  3. tailhook

    tailhook Captain

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    Looks clean, wondering where that boat went. I have the same boat, Looks like you got the deck situation under control.
    Just did a second station last season out of coosa. Keep posting and congrats!
     
  4. tailhook

    tailhook Captain

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    Location:
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    Here is mine.
     

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  5. SlowLoris

    SlowLoris Member

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    Finally got some time off to press on. Finished grinding down the entire starboard side stringer after removing a thru hull and electrolysis plate, made a template of the stringer from 3/4" plywood to be transferred to 3/4" penske. The thru hull wasn't de-cored so added de-coring all the thru hulls to the list.
    Dry fitted the penske, and glued it together with some polyester with cabosil and started cutting glass. Doing one side of the stringer at a time with a vacuum bag, may be do both sides for the port side if it goes well.
    I ground down the joining seam and laid one layer of CSM and 3x 1708 and then put down one layer of light CSM and 2 layers of 1708 full length of the stringer. The top will get a radius ground down then a few layers of biax over the top.
    Laminating the other side of the stb stringer tomorrow and cutting glass out for tabbing
     

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  6. tailhook

    tailhook Captain

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    Looks like you have done this before.. nice work!!!
     
  7. SlowLoris

    SlowLoris Member

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    Was only able to get half the stb stringer tabbed in Monday with the cooler weather (only so many heaters).
    Too cold to laminate the last two days so was able to take down most of the port structure, do a bunch of Grinding and inspect The turbo riser/mixer.
    Should be able to laminate the rest of the stb stringer and start the template for the port side tomorrow.
     

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  8. SlowLoris

    SlowLoris Member

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    The major grinding has finally come to a close (for now). The past week has been grinding, templating and laminating the port bulkhead out of the boat, to be tabbed in. This has made it much easier to work with and I can do it inside which has saved a ton of time with fluctuating weather temps.

    Was going to tab it in today but the moist weather was a deterrent. The tanks are back from Luther’s and decided to prep and paint them with coal tar epoxy (somehow convinced the girlfriend to paint). Also started to remake the tank beds that had to be cut out to prep for new stringer tabbing.
     

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  9. SlowLoris

    SlowLoris Member

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    5 1/2hrs later and the port stringer is tabbed in. Second coat of paint goes on the tanks tomorrow then will start templating bulkheads.
    Going to check engine alignment before the forward bulkhead will go in since it’ll be much easier to do without it in place.
     

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  10. JimRP31

    JimRP31 Captain

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    Great project. Keep posting.
     
  11. SlowLoris

    SlowLoris Member

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    Back for a few weeks to work on the boat before I head out for most of February. This week has been pretty productive so far;
    - Bulkheads are all cut and laminated - ready to be tabbed in
    - Stringers and bulkheads are trimmed to height (ready for capping)
    - Fuel tank paint is finished
    - Took out the rudder and hardware to re-bed at a later date
    - Took off the prop/shaft to replace cutlass bearings and replace the standard shaft seal with a PSS
    - Replaced both Cutlass bearings
    - Fit replacement/extra foam tank supports to be glassed

    This shaft tube has two cutlass bearings (prop side and engine side). I'm not sure if this is standard but I replaced both as they had some play. It seems like a good system as the shaft is always supported, unlike some boats i've seen that only have the prop side bearing. Curious about what other's cutlass bearing setup is?

    I did a bunch of research on removing the shaft coupling but decided to go my own route and rented a puller for advance auto (photos below). This worked really well with a socket between the puller and shaft. Luckily this coupling didn't put up too much of a fight and i'll be putting tef gel on the shaft to keep it that way on the reinstall.

    With no warm days in the near future i'll be limited to smaller lamination sections using heaters.
    I'll cap all the bulkheads indoors and tab them in as I go to utilize the indoor heat.
    More to come...
     

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  12. Toolate

    Toolate Captain

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    You grinding with the Festool Rotax or is that a grinder? Rotax is an amazing tool I have it.

    Lots of discussion on forward cutlass bearing here seems like maybe 55/45 in favor of it (anyone feel free to disagree with me). My take is that if it was there then leave it though I would suggest adding a shaft seal with a water feed rather than a traditional stuffing box like it appears you have. It worked for a long time though so feel free to ignore me :). Most convincing argument against the forward cutlass comes from one of our most experienced builder @fvfirstteam who hard mounts his engines and thus doesn’t believe in the forward support. Personally I can see a reason to leave it out if the engine sits on rubber mounts too but my old boat had one and I left it (rubber mounts) and its been fine for about 200hrs.

    Great progress you’re making!
     
  13. Genius

    Genius Captain

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    fwd cutlass is helpful when aligning the engine. If the distance was short between the gland and the motor on soft mounts, I wouldn't use one. In this situation, it would be handy to have one cut in half the long way, can be used to support the shaft in the log when aligning the engine. Just slide the gland off the log to install, remove when done aligning. If you are doing anything serious with glass, your Festool set up is the way to go. I've got the same and love it, wish I had it many years ago.
     
  14. SlowLoris

    SlowLoris Member

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    That grinder is a festool RAS115, i cant imagine doing this job without it. The ROS is a bit beefier but I feel the the RAS is easier to grip in off angles. The flap wheels (even this tool with no vacuum) are efficient but the lack of dust collection is primitive. Pricey system but well worth it as the cleanup would be a sick joke otherwise.

    I've got a PSS that i'm installing tomorrow which i'm pretty excited about. The "standard" packing system works well but they are a giant pain to maintain when you have to swap packing in the water (or at all really).

    I've stuck with the system of two cutlass bearings as that was what was in the boat when i got it at it seems to work well. It will make aligning the engine a bit easier as i wont have to support the shaft while aligning but Genius' idea would to the trick as well.
     
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  15. SlowLoris

    SlowLoris Member

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    Finally back from work for a week and a half and picked up the shaft and coupler from the machine shop. The coupler came off the shaft just fine last month but on reassembly it was giving me a VERY hard fight, too hard . The machine shop took down pretty much nothing on the coupler to get it to fit and make a new key.
    Now I’m having some alignment issues on the reassembly. This shaft tube has front and aft cutlass bearings which I replaced (they were going bad at the end of the season). I’m at the point where I need to shift the engine to starboard to finish the alignment but can’t because the shaft starts to rub the cutlass bearing.
    I’m curious what others have in regards to cutlass bearings on their jc31’s or of the like. If the front cutlass bearing weren’t there this would be easy. However it was like this when I got the boat, the double bearing seems to be a good idea from an alignment and support perspective, and worked great until the bearing started to go (boat sat for 3 years, not surprised it didn’t last).
     
  16. mudhake

    mudhake Captain

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    can't tell by the pictures, is your engine hard mounted or soft mounted?
     
  17. SlowLoris

    SlowLoris Member

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    Soft mounts. The aft mounts can slide side to side and up and down, forward mounts just up and down.
     

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  18. Genius

    Genius Captain

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    engine gets moved to match the shaft for an alignment. I don't understand how the cutlass is rubbing?
     
  19. SlowLoris

    SlowLoris Member

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    The issue i'm having is when the engine is aligned to the shaft (or so it seems by being easy for both couplings to mate with no cross contact), there is a gap on the port side from 7-11. In theory I would slide the aft of the engine to starboard to eliminate the gap, but by doing so the only way for the two couplings to mate in the new position isn't a smooth connection (its a decent sized shift) and the shaft rubs on the starboard side of the bearing when connected. The front mounts have no side to side movement, otherwise this would be much easier. Going to try to work with it a bit more tomorrow, but looking for suggestions to what is usually an easy process.
     
  20. Genius

    Genius Captain

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    You have to make the front mounts move side to side by slotting them or remounting them.
     
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