Re: How bad?
 

Don't hold me to it, but I don't think it plays a role in structural support. To me, based on everything I've seen, it's just cosmetic, and it was one of the selling points of Mariahs in their brochures, that no other boat manufacturers were offering a custom fiberglass lined engine compartment.

If I had to venture a guess about the mystery water capacity before the bilge pump kicks on, I'd say at least over 2 gallons while sitting level (ie on a trailer, etc). Attached is a pic of when my my old Z250's engine was removed. You can see the distance where the bilge pump is located in relation to the transom. There's quite a bit of real estate there, and depending on how deep your hull is, there's lots of room for water to hide.

You can also see where my fiberglass liner cracked around the port side engine mount. This was repaired and cracked again at a later time slightly forward of this one.

Re: How bad?
 

That is interesting I only have one cut out where my depth transducer mounts. My bilge pump is mounted on top of the fiberglass liner and generally the same position. There is no cut out through the fiberglass liner for it.

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