Factory installed "holes" in rear storage area

I recently purchased a 2015 Tandem Island.
Directly behind the rear seat, in the open storage area, in the center, there are 2 holes penetrating the deck. These are not the rod holders nor the scupper holes on the left and right. (I do not see how I can attach a photo, sorry.)
One is sealed below the deck. It will fill up with water and stagnate, so I plan to place a swim noodle in it.
The other has a plastic plug. Should the plastic plug fail, the hull will fill with water.
Anyone know what these to "holes" are for?
Thanks for your advice.
Bill

I believe you are referring to the "Lowrance ready" cavity and transducer wires thru-hull hole.

The larger one is direct to an area under the hull where a transducer (Fish Finder) can be installed. This is like an over sized scupper hole and does not lead into the hull or hold water. The wire port is above water line and should not be an issue at all.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I actually have a related question. I am not sure whether the holes are the same Bill is referring to... We want to buy a second hand tandem mirage island and identified on the photos the owner sent these kind of sealed holes at the bottom of the boat (see pic). We found 4 of these small holes. We were wondering about the function of these and whether they are truly sealed. Can anybody advise?
Thank you in advance

Those are locations of a molded-in inserts. One for the front of the drive well. Heated brass material attracts more plastic to areas for added strength. They also function as hardware attachment points. The two forward support the Island mast base inside the hull. These are solid brass with a threaded shallow hole on the outside to allow the attachment inside the molds. This holds the position during molding. The attachment screws are removed at the end of the molding cycle, during cooling. Then a "cosmetic" plug is inserted during assembly.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)