Arjay motor mount/stinger repair

Discussion in 'Powerboats' started by PickleRick, Sep 11, 2018.

  1. PickleRick
    Joined: Dec 2017
    Posts: 20
    Likes: 0, Points: 1
    Location: Greenville

    PickleRick Junior Member

    I have an 88 citation, inboard aq211a, volvo penta 290(c?) 23 foot cabjn boat.

    While working on the tilt/trim issues i noticed a caved in motor mount. Cutting open the support i found all wood rotten. The motor moint was essentially a 10 inch 4x4. The rest of the stinger, about 12 inch forward and aft the motor mount was hollow, marine ply wood made hollow square.

    Because of cost savings, time savings, no need to remove the motor for repair im going to pour. Ive removed all wood and shop vacced her dry/clean. Wouldn't eat out of her but clean.

    The stinger isnt fully encapsulated, there are imperfections in factory lay of matt where ill have to seal off holes in the forward and aft section where my pour would run out. Was thining some matt with 5200, followed by brushing on thickened epoxy for a tight seal.

    Ive read that arjay bonds very well to wood. Would it benefit me to put a section of 2x4 wood longways across the transom, expoxied to the hull before pouring to help bond her to the hull? Im looking at less than 4 gallons total for both stingers, less if i use new wood as filler/structual skeleton.

    Thanks ahead of time.
  2. Blueknarr
    Joined: Aug 2017
    Posts: 1,433
    Likes: 404, Points: 83
    Location: Colorado

    Blueknarr Senior Member

    Your boat will catch fire if you do this!!

    Epoxy produces heat as it cures. The volume of epoxy poured into your hollow stringers will generate enough heat to spontaneously combust!

    I'll bet dollars to donuts that the plywood in your transom is also rotted away.
    Pull the engine.
    Remove half of the interior
    Replace transom ply
    Replace stringers
    Replace engine

    Rebuild exactly as original: Unless you have an engineering degree.
  3. PickleRick
    Joined: Dec 2017
    Posts: 20
    Likes: 0, Points: 1
    Location: Greenville

    PickleRick Junior Member

    Arjay is a competitor of seacast.

    Arjay and seacast have all been used for over a decade for transom and stinger repair/building with good results if instructions are followed. The temp of the curing arjay will not exceed 160 degrees she's not a fire hazard. The only super hot when too much is set to cure at one time epoxy I'll be using will be thickened as a glue to fill in the voids for and aft of the stinger so she's water tight, something that wasn't done from the factory. 5200 will be put into the voids and then the thickend epoxy, possibly matt as well if the holes are too great to be filled with "fillers" alone. I just need her liqued tight enough so my pour doesnt go into the bottom of the bilge.

    Transom has been checked and is solid, the transom is also made indepenant from stingers, something the manufacturer got right.. The motor mount was the only solid part of the stinger, the rest was marine ply wood made into a hollow box.
  4. ondarvr
    Joined: Dec 2005
    Posts: 2,896
    Likes: 548, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Do not use 5200 in the holes, go with epoxy all the way if you're going that route.

  5. missinginaction
    Joined: Aug 2007
    Posts: 1,102
    Likes: 254, Points: 83, Legacy Rep: 512
    Location: New York

    missinginaction Senior Member

    Trying to fix an engine stringer using some pour-able quick fix just won't work. If it was this easy, everyone would do it. There are a number of ways to remove/replace rotted out stringers but all involve replacing the core with ply/coosa or even foam, depending on the specific application. There are different methods depending on how the engine(s) are attached to the stringer. Replacing stringers is a fairly complicated project, the old stringers need removal new cores need fabrication and then an installation is done using epoxy and fiberglass cloth and sometimes roving to an appropriate thickness based on the specific application. It's not rocket science but you need to research it so you do it right. I don't have time this morning to go into all the details. There are many posts on this site that detail stringer replacement. I did this myself and you can search for my thread(s) or look at what others have done. The late Paul Ricelli (known as PAR 0n this site) spent a lot of time giving good advice to people who thought they'd do a quick and easy "pour" repair. There are no shortcuts. Don't waste your money and time. Do your homework.

    Read through this post from a few years ago. A lot of good information here. Seventeen ounce biaxial cloth (without mat) and epoxy would be my choice over new cores.

    Stringer And Deck repair
    Last edited: Sep 15, 2018
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.