*siboney 2.0* structural repairs - 1972 58' yachtfisherman

[MarioG]

That looks great! Its real piece of mind having that project complete. Did you support the lower skin/battens while you had all that weight holding down the lose top skin and core? I recall on mine the bottom skin was nowhere as thick as the top skin and I couldn't see weight as my solution for fear of distorting the camber.

the bottom skin was pretty solid enough to build upon with little flexing im guessing due to the framing on the underside where the lighting and headliner is attached to. on the YF the camber in the forward deck isn't that pronounced. it was no factor and any remining irregularities was resolved during fairing in prep for paint..

[MarioG]

Looks great. Nice work!

thanks Jim!

[MarioG]

Pretty work.

Thank you Sir.

[MarioG]

Hi guys! sorry for not posting updates more frequently, but it has been a marathon to complete the structural repairs ahead of the engine installation {next week}.

this portion of the thread is specifically about the dreaded rooftop core rot and water leaks and how I tackled this major problem that many of us know very well. it all started a long time ago when I would notice water dripping down in the corners above the side salon doors and also out of the outboard wire conduits in the ceiling of the engine rooms, usually shortly after a hard rain shower we typically get down here in south Fl. I did the usual recalking of all the flybridge screws but will little success. I suppose for a while I just "delt with it" until a better solution was found. Yes, there was a deep "sag" in the salon ceiling that was visible above on the flybridge and below in the salon about mid ways going forward. Unfortunately my OCD had other ideas that lead me down one hell of a rabbit hole.
So in the beginning of this year, after I pulled out the old engines, and contemplated my next moves as I staired down into the abyss of the two now empty engine rooms, I came to the conclusion that before i embark on putting in two shiny brand new engines, and everything that goes with that, I must address what's above me before what's below me happens. So with that said, I reinstalled the engine room sole hatches and focused on tackling the rooftop problem. But first, let me back up a little bit, about 10 years ago, I really wanted to solve the rain water "pooling" issue that 53MY/58s and up seem to have. apparently, and I could be wrong on this {please fact this} but it seems that the factory in order to 'help" with water drainage from the bridge, small holes were constructed into the bridge wall where the wall meets the rooftop. I assume the idea was that any water pooling would flow through these holes, into the inside of the flybridge and then migrate to another hole on the outside bridge wall and flow out and down over the sides. little did I know that this process was the leading cause of core rot. So in an attempt to solve this seemingly silly solution, I proceeded to remove all the screws holding down the bridge and glassed in the bridge to the rooftop permanently. then glassed in approximately a 2' section of 1.5 inch dia fiberglass tubing into each forward corner on each side of the flybridge. This did solve the water pooling issue, but it did teach me a lot of the major underlying problems that I would find later. while I was inside the flybridge glassing in the fiberglass tubes, I noticed that the backside of the flybridge wall that met the rooftop deck was essentially bare of any sign of calking or sealant. that thought never left my mind. for a while the leaks seemed to slow down but I knew that was a ticking time bomb. eventually after a few seasons, the leaks were back. this time, I knew where I needed to go. so with a 2" hole saw in hand I headed back up to the fly bridge and proceeded to drill a series of holes along the bridge wall starting drilling just aft of the drain tube and worked my way aft along the wall. immediately, upon drilling out the first hole I noted that the core was essentially gone. literally hollowed out and wet. the subsequent holes drilled further aft were the same until I reached as far back as the flybridge hatch. I knew at that moment that the roof core was gone and there was no easy way to fix it.
Fast forward back to now, since I already had the entire salon interior removed to facilitate the engine removal process and having the salon floors already covered and protected, I proceeded to rip down the entire headliner. it was evident that the bottom side of the fiberglass of the roof was showing signs of moisture with patches of brown stains and water marks. my plan was straight forward, cut off 3 foot square sections of the bottom skin of the fiberglass roof and see where it all goes. well, as you will see in the pictures, it quickly turned into a major nightmare.

BE ADVISED, THE FOLLOWING PICTURES OF THE INSIDE OF WHATS LEFT OF THE BALSA CORE IS NOT FOR THE FAINT AT HEART! I SUGGEST YOU SIT OR LIE DOWN.

[MarioG]

Cutting off the bottom fiberglass layer.

sorry about the sideways pictures. this forum cannot edit uploaded pictures.

[MarioG]

eventually the entire ceiling needeed to be cut away exposing the major damage. the rot and mold was horrible and disgusting. but we pressed on regardless.

[MarioG]

after getting over the inital shock of the immensity of the size of the problem, we proceeded to grind away all the rot all the way smooth to the upper fiberglass surface.

[MarioG]

and more grinding

[MarioG]

if you notice in the last picture above, you will notice that i used a floor jack to push up the sagging rooftop back up close to where it belonged. note, the ceiling has a radius that is more pronounced over the aft salon doors and shallows out as you move forward. the fwd section above the helm is a very shallow radius when compared to the aft section. go easy on the jack so you don't rip off the roof top from the salon sides! in order to keep the rooftop from sagging in further, we placed a series of 2" studs to stabilize the roof.

[MarioG]

So now that the entire roof was cleaned of all the rot. i designed a truss interlocking grid system made of 1.5" thick Cusa board. we traced out each individual truss to take into account the specific radius and uneven imperfections that each truss required. we did this by simply nailing a length of 4" board to the very top of each stud holding up the roof. then with a pencil and a cardboard cut out to track along the ceiling while the pencil transposed the pattern onto the board. I numbered each board to keep them in order then took the boad off and with a jigsaw cut out each unique pattern. from there, i took the patterns to by cousins CNC machine, we traced the patterns onto a large paper and took a digital picture of it and uploaded it to the CNC machine. after a few test cuts, we proceded to cut out the trusses on the CNC. the CNC did etch the numbers on each truss