Hatch replacement on an '85 Mac 25

[Seadoc]

Have any of you had experience replacing the forward stock deck hatch with one that has a transparent lid? If so what brand was used and what steps were needed to adapt it to the Mac 25 deck
(for example adjusting the installed hatch frame for deck camber and depth)?

Thanks in advance for your collective wisdom!

Seadoc

[Wyb2]

Just bought an '86 M25 and this is tentatively on my list of things to do. Since this is a molded-in hatch (vs a rough opening in the deck with an aluminum hatch frame installed), I'm guessing getting any off-the-shelf hatch to fit would be a small nightmare. My plan right now is to simply cut the center out of the existing hatch cover and install a sheet of smoke/clear polycarbonate over the opening. A 12x12" panel of 1/4" polycarbonate can be had for $30 or less. I'm thinking bevel the edges, countersink the mounting holes, install with flat head machine screws and cap nuts, and it might not look half bad.

[Massey]

Have any of you had experience replacing the forward stock deck hatch with one that has a transparent lid? If so what brand was used and what steps were needed to adapt it to the Mac 25 deck
(for example adjusting the installed hatch frame for deck camber and depth)?

Thanks in advance for your collective wisdom!

Seadoc

I’m not sure if it’s a year thing or not, but am M25’s I have ever seen have a fiberglass deck hatch. Here is mine in the pic below. Maybe someone more familiar with the changes over the years can shed some light on the 84-86 possible changes. Mine is an 83.

[JohnnyP]

My 224 (I know, lightyears away from the M25) has a round pop vent in the forward hatch cover that may or may not have been factory; however, I am considering the same upgrade. I am considering two options: 1) going with a completely custom polycarb lid that would be a direct replacement for the factory one; 2) heavily reinforcing the factory hatch and cutting out an opening using a CNC router (for precision, naturally) to which I would affix a 1/4"-3/8" sheet of polycarb which would allow light into the cabin while also be strong enough to catch a wayward foot.

Because I am borderline insane, those are my options; however, the "pop vent" may also be an option for you as it does let in a decent amount of light in its open position and you would not have to worry about compromising the structural integrity of the hatch by cutting the 4" or so hole in it.

[Wyb2]

Have any of you had experience replacing the forward stock deck hatch with one that has a transparent lid? If so what brand was used and what steps were needed to adapt it to the Mac 25 deck
(for example adjusting the installed hatch frame for deck camber and depth)?

Thanks in advance for your collective wisdom!

Seadoc

I’m not sure if it’s a year thing or not, but am M25’s I have ever seen have a fiberglass deck hatch. Here is mine in the pic below. Maybe someone more familiar with the changes over the years can shed some light on the 84-86 possible changes. Mine is an 83.

My '86 looks exactly the same. What I'm thinking is cutting a square-ish hole in the existing hatch cover and installing some transparent polycarbonate with ~1" of perimeter overlap for mounting hardware and sealant. So a clear or tinted panel where I've drawn the grey box.

My 224 (I know, lightyears away from the M25) has a round pop vent in the forward hatch cover that may or may not have been factory; however, I am considering the same upgrade. I am considering two options: 1) going with a completely custom polycarb lid that would be a direct replacement for the factory one; 2) heavily reinforcing the factory hatch and cutting out an opening using a CNC router (for precision, naturally) to which I would affix a 1/4"-3/8" sheet of polycarb which would allow light into the cabin while also be strong enough to catch a wayward foot.

Because I am borderline insane, those are my options; however, the "pop vent" may also be an option for you as it does let in a decent amount of light in its open position and you would not have to worry about compromising the structural integrity of the hatch by cutting the 4" or so hole in it.

Polycarb is very tough stuff, much more so than acrylic. It will dent before it cracks. I just looked at Lewmar's website, they use acrylic for all their hatches, and they only use 8mm (5/16") for their smaller (13x13) hatches. If you don't skimp on the mounting hardware I would be surprised if it had any meaningful impact on the structural integrity of the hatch. Downside is polycarb is less scratch resistant and will yellow over time from UV.

[steve4]

someone had done what you propose to my M25 before I got her, complete with a solar-powered vent fan. The light is nice but, the screw holes aren't sealed well and now it leaks pretty bad into the v-berth. Just had to pull out and wash the new cushion covers we made.

That said, I'm trying to figure out if it makes sense to try and repair mine or just start over with a whole new hatch so I'm curious how yours turned out.

[steve4]

After a LOT of learning and effort, this is the result of my attempt at disassembling my aforementioned hatch, re-gelcoating, and re-sealing everything. Not having much experience manually color matching paint, I opted to just stick with whatever version of white was in the can of Evercoat that I bought at the local marine store.

Here are a few from before/during repair.

[Wyb2]

Looks pretty good from here. And yeah that’s roughly what I’m planning to do (minus the solar fan probably).

What did you end up sealing it back up with? I’m always amazed that there seems to be an endless supply of previous owners that think holes in a boat don’t require sealant.

[steve4]

This stuff called Lifeseal. It's messy and gave me a lot of frustration since I had just made this nice pretty white finish then ended up with black smudges and finger prints I had to clean off from not realizing I had some on my fingers....



That said, I trust the guys at my local shop and that's what they recommended.

The solar fan was part of the original "MacGuyver job" so I didn't bother with it. Pretty sure it doesn't move enough air to be of much use on the boat but, one less thing to change I guess.