This is really a DIY job. If you have to pay a marina $125+ per hour to fix easy problems like this you'll be broke real soon. Unless of course you were a Mega Lotto winner.
well said! If I had to pay a boatyard to perform all maintenance on my boat, I wouldn’t be able to afford the boat. In addition to saving lots of money, you will become intuitively knowledgeable about the systems on board. You will immediately, without thought, know what thru hull assemblies & hoses connect to. Unfortunately, when buying a used boat, that is almost 40 years old, you have to establish a baseline for future maintenance. That means replacing
EVERY thru hull assembly ( thru hull, valve, tailpiece, backer block, & hose) with proper bronze fittings, marine grade hoses & clamps. I replaced all on my Hunter 33.5 when they were approximately 15 years old. Grind off the mushroom portion of the thru hull fitting on the exterior of the hull & pull/remove the remaining assembly from inside the boat….easy peazy! Chisel off the old wood backer & fabricate new ones using G10 fiber or plywood donuts soaked in epoxy.
The raw water intake assembly (shown next to the raw water strainer), is a disaster waiting for a time & place to happen. The original hose appears cracked & rotted; when it fails, your boat sinks. Keep a set of conical wood plugs to plug the hole in an emergency. Also, keep the valve closed until you replace the hose. Good habit is to close all thru hull valves when you’re not onboard.
Photo #2 shows the plastic shaft stuffing box & hose assembly. My Hunter had the same configuration. The old hose & flax packing should be replaced, better yet, convert to a Volvo shaft seal that eliminates the plastic fittings, hose, & packing.
I personally wouldn‘t be concerned about the plastic speed/depth transducer yet.
All of this probably seems a bit overwhelming & yes, expensive; however, if you tackle one system at a time, you will become an ”expert” like everyone else on the forum! Don’t hesitate to ask questions when you need answers.
One final thought & bit of advice about learning to do repairs yourself. I can’t count the number of repairs that boatyards have done, that I have had to go back & fix myself either for poor workmanship or use of inferior materials. Learn to do these maintenance tasks yourself when possible.