As you can see, this is the second boat I've owner that I've had to repair a bad hull to deck joint. Not surprising really, since this is common and to be expected problem on boats of this vintage. The hull, deck, and liner of both the Compac 16 and Starwind 19 are held together with an exterior flange joint - over time, stresses on the hull, deck and liner, as well as the natural decay of the adhesive degrades the seal/adhesive and causes leaks and weak spots in the hull/deck joint.
Unfortunately, many boat owners (including the previous owner of my Starwind 19) cheap out by trying to silicone the rubrail onto the joint to stop the leaks. This is NOT the proper way to fix the problem, and will only make a mess and lead to ongoing leaking in the near future. Calking the rubrail doesn't actually rebond the joint - eventually the caulk gives way and water can again enter the cabin. In addition, the weakened joint creates structural instability in the deck that cannot be repaired by simply caulking the rubrail in place.
To properly fix this problem, here's what you need to do: carefully remove the rubrail and set it aside. Here's what you're likely to find:
I used a belt sander to remove the old sealant from the face of the
flange. The S19 hull/deck joint was originally held together with
staples
(yes, staples - shot in from the bottom - see below), you'll probably
find that many of the
staples have rusted out and no longer provide any stability to the
joint. If the
adhesive is at all worn out, this will allow you to gently pry the joint
apart. Do the best you can to remove all the weak or deteriorating adhesive
from the joint - this may mean you actually have to pry the joint open in places
so that you can remove the old stuff and make room for the new. Expect it to be
tenacious; use a scraper or bent coat hanger or whatever you can to pick out as
much of the old stuff as possible. Leave the places where the joint is still
sealed alone, but anywhere the joint is bad you should remove the old sealant. As you can see, in my case, this meant that you could actually see through the hull/deck joint into the boat!
Once the joint is cleaned of as much of the dodgy adhesive as possible, drill holes through the joint to receive #10 SS bolts every 8 to 10 inches. Clean the joint thoroughly with MEK or Acetone on a rag, then, gently using a pry bar or screwdriver where necessary, open and reseal the joint with 3M 5200 - DON'T just smooth 5200 over the outside face of the joint, you want to actually bond the flange itself together. Install and tighten the bolts, nuts and washers, and smooth/feather the 5200 that squeezes out of the joint across both the inside and the outside of the joint (i.e. inside and outside of the boat.) The 5200 will take 48+ hours to cure - If you're in a hurry, you can wait until the 5200 gets tacky and then cover the joint with duct tape so that they can immediately reinstall the rub rail.
Depending on its age, expect the rubrail to have shrunk. Lay it in the sun or submerge in a bucket of hot water in order to make it stretchy again, then, bolt the rubrail at one aft corner and stretch it forward to the bow. As you do, let the rubrail rest above the joint (ie tight to the lifeline stanchions) - DO NOT fit it to the joint as you move forward. DO slip the rail over the joint at the bow, then come off the joint, again laying the rail against the lifeline stanchions until you get near the other aft corner, where you will again fit the rail to the joint and bolt it in place. It helps to have 4 hand here - two to hold the rubrail stretched tight, and two to rebolt it. If you're on your own, some clamps will be helpful. The key here is that you want the rubrail as tight as possible - if you fit it to the joint as you work forward and aft you won't be able to get stretch it to a tight enough fit, and on hot summer days the rubrail will get loose and sloppy. Once you have the rail stretched tightly above the joint and secured at both aft corners and over the bow, you can go back and stretch it into place over the joint. This will ensure a tight fit and no sloppiness later.
Sounds like a lot of work, but I've done this to two boats now and it's really pretty straight forward. If you do it right the first time (right = getting the old, failed adhesive out, thoroughly cleaning the joint before resealing, and bolting for additional strength) you will probably get another 20-30 years out of it, depending on use.
