Yep. I was almost dumped over a few years back, in my aluminum boat, by a freighter wave that caught me sideways. Since then, I am very mindful of the ships that pass me. I still have that boat but have switched to a bigger, safer craft for the Sound.
I found a couple guys drift mooching in the fog last season. They asked me where they were. When I told them Lagoon Point on whidbey Island they turned white. They put in at Kingston and were so stoned they didn't realize they drifted across Admiralty Inlet,
You cannot count on tidal currents to take you down the shoreline in a controlled drift.
I see people out in the sound in float tubes now and then. Very risky. I don't think most people realize how fast the tidal currents are or how fast the wind can kick up. Also, riding the wake of an 18 ft Bayliner in a float tube would be risky, let alone a tug boat or freighter. Might be ok in a pontoon on a nice day. At least with oars you can get around better.
Number one recommendation would be to try out your vessel of choice at your chosen location WITHOUT trying to fish. KISS principle, at least initially. I'm hoping to do that in my yak in October on the Yakima. It will be with a group (PSFF), so we'll have some "backup". Still, first float will be just that, "float". No fishing, take pictures, and figure out what's best for location and fishing.
Unless your craft is bright colored, I would strongly suggest adding some hi-vis orange (like hunter vest) so you can be seen by the motorboats. There are some very strong currents and rips around the sound, so do some homework before venturing about and by all means, wear a PFD.