Does indeed sound like the typical pump shaft seal
There are "weep" holes on the pump body to allow the leaking water to escape and also provide detection of the problem. On some engines, but not yours, the leaking water can enter the engine
crankcase undetected without these holes.
If you look, maybe with a small mirror, you can see these holes and often some salt water corrosion
on the pump body. On your pump mount bracket the leak should be dripping near the middle of the bracket. May be hard to see the holes with that channel shaped bracket.
You can continue using the engine but should repair this as soon as it is convenient. Monitor
the issue with though, and do it sooner rather than later.
If 200 miles gets you "home" that shouldn't be a problem. And this is a repair you can do yourself if you are so inclined. It's not that hard and will help build confidence in your ability to take of things yourself.
Finally, my usual admonition to aquire a service
manual for your engine. If you are mechanically inclined and can use a manual you may be surprised how much you can do yourself on common boat maintenance