I've replaced the hatch lenses on two boats, which doesn't make me an expert, but I was impressed by my shop's insistence on having the old hatches in hand. "Measurements never work," was the quote after I handed over my beautifully drawn spec sheet.
They want the original as template so they can copy it exactly. And when you pick up the new plastic, you can compare to the old.
They want the original as template so they can copy it exactly. And when you pick up the new plastic, you can compare to the old.