Possible hull damage?

[ProjectPat]

I have an 88 Sylvan Pro fisherman 16' aluminum boat. After a recent outing in some rough water my pass through windshield became separated and came through past the other windshield it rests on. I was able to flex the consoles and pop it back through but now the mark on the aluminum where it's been resting on in the past is off quite a bit. There's almost no play in the consoles and they don't seem like they shifted at all. Now if I hit a wave the window pops through very easily and I have to struggle to get it back on the outside where it's supposed to be. I already needed to replace the floor so I pulled it up to take a look at things underneath. Previous owner put a floor over the original so it was quite difficult to get everything out and cleaned up. It appears that there's nothing broken that I can tell. I was expecting to see some sort of cross bracing or stringers underneath but it doesn't look like it. I'm concerned that there's something I'm not seeing or that there's so much flex in the hull now it might not be safe to take out. Other pictures I've found of similar aluminum boats show a cross brace in front of the consoles on the bow side but all I'm seeing is some crudely pieced together lumber. Could this be the problem why it's flexing so much?

 

[Grub54891]

well, something isn't right. I dint know what it is but it shouldn't flex that much. you might have to dig deeper to find out what's missing. The area ahead of the consul/windshield is suspect at this point.

 

[cptbill]

Seams to me if you can't find anything down low you have to start looking higher up to find the point of your flexing. Like maybe where the consoles attach to the upper hull or even the wind shield it's self

 

[ProjectPat]

Took the floor up in front and found an aluminum brace just flopping around. Looks like there's other pieces missing too because there's a bunch of rivets popped up. The guy ran some 2x4's across the hull in front of the consoles and I feel like that should be aluminum tying the walls together

 

[jbcurt00]

The thin metal strip across the top of the stringers is the only cross ties.

IMO, the deckover the original deck gave way and the deck simply flexed under a serious pounding.... once it flexed enough to mpve, its continued to do so under less pounding..

There should be no wooden framing below deck and except except the hull ribs, the stringers across them and the thin cross strips across the stringers there is no other structure made of aluminum below deck either. Might be a small bulkhead fore and aft of a below deck fuel tank (which I see no evidence of, but I'm using my cell) or fore/aft of a ski locker, which may have been offered in some models using the same hull &/or on yours. Its the big open cavity amidships...

If the deck was soft and a new deck laid over it, its also likely that the gunwales on your boat moved, if only slightly. its a known problem running a boat w soft deck, creates chine and rib end cracks if run long enough...

IMO, you got the deck out, its time to gut it, remove all the foam and thoroughly inspect the hull, chines and rib ends.

 

[ProjectPat]

There are two thin "straps" (picture A) from starboard to Port riveted under the deck to the two aluminum "beams" (picture B)t run from fore to aft to support the deck. These straps must of been attached to the deck underneath by rivets on the ends of the straps and riveted through the deck to the beams. When I'm outside the boat pushing against the gunnel on the port side by the console there's significant flexing and I can see the strap going loose then tighter when I let off. This doesn't happen with the strap that's near the stern. I removed the foam around the rib ends those all appear to be fine the rivets are tight. The riveted seam of the chines is at the rib ends (picture C) and those both seem to be ok as well. Would a cracked rib(s) give the boat flex like I'm seeing at the consoles or could it be simply that the deck and straps completely failed making the boat flimsy so to speak?

 

[jbcurt00]

1st: Dont flex it anymore....

Thats why they crack, movement. And because you no longer have a deck and no verticle support below the gunwale it mimics the soft deck I mentioned....

Aluminum work hardens and cracks, so if it isnt cracked now (yet?) it will be, sooner if you push/pull on it.....