1987 46 post salon side windows

Rotton wood around the window frames most likely or loss of a support. The weight of the flybridge above them then was bearing on the windows and they finally cracked under the weight.

does the 87 Post have a wood house?

I do not know what would have caused them to crack the tracks are teak and I am sure they could rot but I have not heard of the problem in that vintage Post did the crack start at the top or bottom or on the side edge that might help also were you in some really rough seas

I can tell you how to replace you have to remove the top valance and the corner in the rear where the cables and wires run also the trim that runs underneath where the rope lights run if you have them when you get that done there is a apprx. 6x2 heavy piece of Mahogany with about 20 large wood screws that runs the full length of the windows it is also glued in with dolphinte or some similar product, that is the difficult part you have to carefully pry / work that long piece off with out cracking the good windows when you get that removed the windows will tilt in from the top then lift out of track and remove, what I did at that time was to then to place all the windows in the outside tracks and seal with windows urethane I live in Fla and never opened the windows any way also this is the way Post started doing it in the early 90s if you are interested I can tell you how to do it

No it is fiberglass............Could be the cat whiskers are rotted or worn out and the impact of a heavy sea cracked the window.

yes
first you need to remove the front of the box that the wires and cables from the port engine run up to the hardtop in the left rear corner of the salon then once you remove the panels where the track lights are mounted under the valance you ( look up between the windows and the valance) you will see the screws that hold the valance in remove them and move valance out of way then you should see the screws that hold that trim in place it runs the full length of windows in one piece and and is difficult to get loose it is heavy and you will probably need help to remove if that piece has not been removed before it is really stuck to the cabin side it fits really tight if all your windows are broke not a problem but if you are trying to save one or two panels get help and try to work free very slowly or you will break the other windows as it seems old safety glass gets brittle with age then the windows just tilt in at the top and lift out hopes this helps it has been a few years but that is how I remember it as I said earlier I would consider cutting
the aft window smaller have some trim pieces made and stack all windows to outside and seal them up less problems later if you do decide let me know and will give you some pointers

Wait a second guys. The OP needs to give us more info on when and where the glass broke. Running in heavy seas. On the hard. At the slip. During a windstorm??? Did my son hit it with a baseball? There are hundreds of reasons why that glass may have cracked or broken. We don't even know what it is he's describing as a crack? Is it shattered. Is it a centerline horizontal crack or vertical. Is it in the corner ? Just my 2 cents

The one thing I forgot to point out is that heavy piece of trim that you have to pry off also has the window track attached that is why if you wish to save the windows you have to be careful and do not twist it you have to work it from end to end with that said the windows in the Post are really put in well as you will see, that trim piece straddles from the aft of the salon to the front and is attached in multiple places and is quite sturdy and will support that span quite easily it is built like a brick ---- house, I do not know what broke your windows but I do not think it was structural unless the boat yard dropped your Post or really twisted it when blocking I would think something must have hit your window or windows but you should be able to determine when you disassemble

Use Laminated glass. Tempered glass shatters very easily and Laminated is more foregiving. Most yards will flat out refuse to remove tempered glass windows (if they're leaking) because the chance of breakage is very high. I would take a really long and hard look at your flybridge supports.

salon windows

Post used dolphinite which is not as bad as 5200 but is close I used what I call a Stanley wonder bar which is a short pry bar about 15 inches long with a rolled end used for removing nails start at one end at the top of the board and start prying while working your way to the other end pry it gradually from one end to the other to try and save windows like I said before take your time as far as the vertical track in the back you will have to slide that aft window forward to clear that vertical track
I broke one of my windows while removing and replaced with laminated like the original at a cost of around 200.00 also now is a good time to move all of the windows to the outside track and seal the windows like Post did in the later years if you want some tips I will try and help you you will need plastic strips made and you have to cut the aft window it would probably cost 300.00 to 400.00 but it really cleans up the look and seals the window the also I hade a glass installer urethane all of the glass where it meets the fiberglass no more water to the window tracks

I did some window track work years ago and couldn't get one of those top boards off.

Hopefully I can explain it clearly. When you look at the top rail, there is only a small piece of the board (1/2"x1/2") that is keeping the tracks and windows from tilting in. I cut that piece off wider than the center window. Without it, you can access the tracks. I can't remember how the tracks were attached but you may be able to get a saw blade between the tracks and wood to cut any nails\glue. The center window can now tilt in. In theory, the front and back windows can slide to the center and come out. I couldn't get the front window out and had to break it.
Whether you put the windows back in with new tracks or seal permanent, they can be installed through this center part. The small piece of wood can be screwed back in place at the end if it is needed.

An alternative if the whole board won't come off. Pretty big job to start now. Sure it can't wait until winter? I did mine under the shrinkwrap which was great. Good luck.

Windows

The header board with some work will come off I have taken off on two Posts a 43 and a 46 it was a pain in the butt, just need some patience and a pry bar

Windows

Glad to hear you got that board off the rest is easy I do not know which window was broke hopefully the center which is already loose, the rear track should not have to be removed just slide the aft window forward if you need too and it will then tilt in to remove, a lot of people silicone that aft window in because they will leak under way in a windy/rough conditions, hopefully the info I provided helped if I can be of any more help let me know also the glass in my boat had a slight tint I think they called amber but not sure, all the Post's that I have seen do have a tint the glass

Mine are gone at this point. I can describe what was originally on the sliding window: It had a stainless U shaped piece that was around the rear portion of the glass and extended inside. That part had teeth on it with a key lock that slid over the extension and locked against the metal weatherstrip on the rear window. I have never been able to find these online to replace.

The only thing I can find is this:
Perko Sliding Window Lock and Anti-Rattler

Not sure how well it would stop the window from sliding. Should do something.

Hi Ruby

Does our mutual capt friend at WSM have sliding windows?