That's a poorly designed light and was installed later because of tracvision. A boat requires a all around white light for anchoring and also for underway. Splitting the light at the same position would have me asking why? Splitting it in two locations I would understand (one forward and one aft) to keep the light from shinning into the pilot house.
https://www.boatus.org/study-guide/navigation/lights/
I think they're just a screw on the bottom ... but I can't remember for sure I can go climb up tomorrow morning as i put the boat awayStill can't figure out how to remove the lense to get to the bulb - is there a trick?