Mariner 420 2004 - water in swim platform

[Lruel]

Hi,

The core underneath the swim platform is delaminated on nearly half of the platform. My fiber repair guy is telling me that this is cuased by water getting in and out of the platform via the flaps at the end of the platfom. He suggest sealing these to prevent water from coming in after the repair is done.

My question is: if their are flaps at the end of the platform, it mus be because it is expected, by design, that there is water in the hollow platform. If so, does anyone know where that water could come from, if not from the flaps? Are there drains that are just connected to the hollow platfom? That would just fill it up if the flaps are sealed?

Any idea on how to fix this so that problem doesn’t come back?

Thanks in advance!

Laurent

[Tireless]

Do you have a swim platform storage box? If so, this is a big problem for Carvers as the water gets into the core via the mounting screws that were used during the installation of the box. I had just removed the inner liner of my storage box and re-sealed the screws to prevent this very thing.

This may not be your issue, but this can be a problem.

Greg

[Viper]

Do you have pics you could post of the platform and these flaps you're talking about?

[g36]

X2 on the dock box issue

[Lruel]

Hello and thanks for the speedy response

There are compartments where the master cable is and some storage. Not sure if this is what you call a storage box?
Please check the picture of the back of the boat, you see 3 doors, this is where the storage area is.

For the flaps, I do not have a good photo but the second photo shows 1 flap on the starboard side (red arrow pointing at it). There a 2 other flaps, 1 in the middle and the other one on the port side.

Thanks again for helping me on this.

Laurent

[Lruel]

Did some more research and this is exactly "the flaps" I am talking about. Its really called a scupper valve (sorry I'm a French Canadian, so my vocabulary lacks a bit). See the photo below.

Laurent

[Tireless]

Your storage box looks like it is formed to the knee wall on the cockpit. I don't think that would be your issue. The storage box I am referring to is a separate box that is installed on top of the platform.

Water can get into your platform or deck anywhere there are screws or fasteners through the fibreglass. The water then wicks into the balsa core. The longer it is left, the worse it gets.

Greg

[tomschauer]

I don't have a mariner, and can't tell you for sure, but as you have found, those flaps are scuppers. They are there to drain water from your cockpit. You can't block them off or your cockpit will fill with water.
I would look for anywhere someone has made penetrations that were not factory. I see you have underwater lights, did the drill holes for those or anything else in the transom storage compartments and not seal them properly?
Hopefully, you can find the source of the problem.

[tomschauer]

It also looks like you have some kind of access holes on the underside of your platform. I am pretty sure they are not from the factory. I believe I would start there.

[Lruel]

Hi,

I don’t think the lights are the issue since they are transom mount, a lot lower than the hollow platform.

I looked at what i could for the cockpit drains and they are connected to a drain on the side of the boat. But there may be other drains that i have not seen for sure.

The acces holes are actually vents connecting to the outside of the knee box at the rear of the cockpit.

Is there a way to get the plans from Carver? Understsnd their design intent?

I will definitely look for other drains coming in, but this means almost opening the platform on all its surface… kind of an expensive thing to do

Thanks for your responses and pls keep them coming, there might just be an idea that will spark from our discussion

Laurent