Re: Irwin 28 head help
Not giving you a hard time, but the year of your boat is not in the title or in your first post. Yes, I know it is a Irwin 28, but depending on when it was built, it might be a II. That's what I meant by model.
Anyway, I'm not familiar with your boat but I looked it up to see the layout. Yes, there probably is room underneath your V-berth for a tank. But, most boats I see have tanks underneath settees and that would be an obvious place as well. Not sure how big your cabinet is, but one might fit there as well. Are there any holes anywhere that hoses may have been run thru? is there a pump out fitting on the deck even if there is no hose connected to it?
Regardless of where a tank may have been installed at the factory, where is the most convenient, easiest place for you to put one? They may not be the same place.