Yes, it was a very good radio. i especially liked the frequency switches. Sometimes you find them for sale on eBay.
We too had it wired into the ship's battery - which I assume your unit was also. We used a handheld speaker/mic/ptt combo as DanW mentioned.
As to wiring it to your ship's speaker/boom_microphone/stick_ptt we never did that nor do I know how it could be done. Unless there is a non-factory connector unseen in your photographs the only way to implement that is is via the two jacks on the face of the radio.
I am unsure which pin-out of those jacks are (nor the size) but might be "easy" to figure out. Maybe look for a speaker/mic listed on eBay or Amazon and cut the cable off it to use for connections to PTT/speaker/mic.
Bottom line is that the simplest thing to do is use a speaker/mic/ptt.