Hey better late than never. I like this option because a quick look shows it saves an hour in commute time coming from Detroit airport. Are the wrecks in this area marked with buoys, what are the depths and what is the surface swim like in terms of distance?
When are you planning on visiting and with what equipment? Are you comfortable with river diving? Or do you want to hit the big lake no matter what?
So if you want to hit the river for wrecks and souvenirs there's 3 levels of diving.
1. Port Huron boardwalk is mostly a drift dive. However if you read my post about the sturgeon dives, you can make it to the wreck of the Tremble and back to your original entry point. South of the Black River in a massive dirt parking lot are 3 wrecks joined together at the bow and depths are around 5 to 25 feet and it's out of the major current.
2. St. Clair. The St. Clair boardwalk is about 10 miles south of Port Huron and the river is slower there on most days and you can easily go upstream. Right out from the large brick hotel in the middle of the river is the massive wreck of William Wolf. It's in 35 feet of water, but you will have to navigate underwater from a compass bearing. Most of the diving is done near the breakwall where there is much more items going to 25ft. Once you hit 30ft and in the channel, it's essentially desert until the Wolf's wreck.
3. Marine City. The current swings from very slow to fast depending on the wind direction. The entire length of the city is open to divers from the main beach down to the old ferry dock. 2 busted up wrecks lie in 20ft of water exactly 35 yards off shore. (Past the weed bed and on a slope) don't go past 30ft as there's nothing there.
4. Algonac boardwalk. Depths can get a little deeper here. Parts of the boardwalk just short off the breakwall can reach 50ft or so. Lots of bottle and such. Current is dependent on the wind, but rarely strong enough not to swim against.
I recommend visiting Anchor Bay Scuba in Fair Haven. They know the river quite well and will be able to give you landmarks to take bearings for.
As for Lake Huron shore diving, you gotta keep an eye on the weather. It's been chocolate milk as we've had lots of rain and North winds the last week and the shoreline has been hit hard. I'm trying to find some GPS #s for the shore sites and public access might be a challenge on some. Harbor Beach is your best bet as of now though Port Austin reef has some interesting rock formations along with tons of shipwreck wreckage (not a lot of hulls).
