Hello Can111
Welcome
I have never been in Lake Huron but have done some shore diving in a somewhat larger lake just to the northwest of Lake Huron. My comments are based on that (We were out last weekend and dove the wreck of the Hesper).
We drive 1/2 hour north from where we were staying to the dive shop to be informed they had rented all their equipment to a dive charter for the day.
Quit relying on dive shops. They complicate logistics considerably. Get your own gear, early on, including tanks, if you're serious about shore diving. There are various alternatives for used and lower cost gear. Ask questions here if you decide to go this route.
The wreck is marked. We start swimming ... and swimming ... and swimming.
I make it a rule to scout shore diving sites before the day of the dive whenever possible. There is no substitute for looking around with no pressure to actually make a dive. That allows for an in-person verification of any facts, and a check of visibility, shore entry/exit conditions, whether the buoy is actually there, parking, and so on. I find this sort of scouting to be fun, and I can do it on days when I can't dive due to time constraints or weather.
My husband says he watched us for about 1 - 1.5 hours struggling to get to the bouy. Had to swim on my back for a lot of the time because on my belly waves would wash over my head and get in my snorkel. Question 1: should we have dove and worked my way over under the water? We considered this but didn't want to waste air.
Typically I would swim under water most of the way and surface if needed to look for the buoy. But I would use an oversize cylinder or twins. You could use an HP120 cylinder, if you can find one to rent borrow or purchase, if you revisit this site. Another fact to consider is that underwater navigation is a skill that requires practice for proficiency.
At one point I flip on my stomach and see the wreck. THRILLED. I yell to my buddy we made it. For some reason he wanted to keep going to the bouy. Like he thought it was the "beginning". So we struggle on because it is still about 100' away. We never make it to the bouy because the waves kept pushing us away.
Either the conditions were too poor for a safe dive or you need better fins. Shore dives that involve traversing distance, like you're doing, call for long, stiff fins. If you have short fins or split fins that may be part of the problem. I have Cressi Reaction fins that are about 30" in overall length, and have thought about replacing them with freediving fins (which are even longer). There are other good fins, but take a look at those and compare them to what you have, and see if there's a difference.
Finally i say let's just dive here. Buddy says ok. I descend about 20' down to the sandy bottom of Lake Huron, of course the wreck is nowhere to be seen. Buddy doesn't make it down at the same time. i wait for him for about 3 minutes (question 2: is that too long?) It felt good to just relax at the bottom and not be in the waves. He finally appears briefly but then pops back to the surface. I wait longer for him again (3 ish minutes) and then finally go up also.
The usual convention is one minute, but it's something you should cover during dive planning.
... I talked to my buddy and asked why he bailed and went to shore. He said he had trouble descending. (lost about 30 pounds this year and reduced his lead), the dive flag line was "twisting and bugging him", and he was just plain tired from the waves.
It seems to me that you could benefit from planning some dives just to work on skills together. I do that with my kids, and it helps, not just with the skills but with helping understand each other's limitations, expectations, and assumptions. With shore diving this stuff is more important.
Also, usually I try to take turns with the flag, since it is more work when pulling it.
One more thing. When I got home i consulted my Great Lakes Dive book (by Kris Kohl) and it said my dive was 800' (!) from shore and to get to it by boat! The first dive shop said 200' the second said 300'. I had stressed to the dive shop we were inexperienced, surprised they sent us there.
The best construction I can put on it is that there may be portions of the wreck that are closer to shore than the buoy. ::shrug:: In better weather I think you would have had a much easier time of it.
So people help me learn from our outing. What did we do wrong? Is there a dive stress-light that i would use to my shore person in case i really was in trouble?
I would guess that, in reality, the main problem was that the wind conditions were not favorable the day you were diving, and neither you, your buddy, or the dive shop realized it.
With shore support, make your expectations clear and talk about what does and does not constitute an emergency. Be very clear about your timeline, and allow enough time that you are sure you will be back even if there are delays. They will respond to your confidence or lack of it. Again, dives at a benign location, even if it is a boring location, will help with this.
Signal wise, you can carry a strobe light if you want to be able to make an unambiguous indication that there is an emergency. Or just use the standard "crossing and uncrossing of arms stretched vertically above the head" hand signal. Again clarity with your shore support people is important, especially at first. My wife got much less stressed out with my shore dives after the 20th one or so.
What can we do different next time?
I hope you keep diving and work through this stuff. The first steps are hard and I remember some of these problems.
1) Get some of your own gear. Better still, get a full set of suitable gear.
2) Consider larger cylinders for shore dives (assuming you can handle them physically). Call around, some places may rent them if you want to experiment.
3) Work on skills in shallow water near shore even if there is nothing cool to see. There is much more to diving independently than diving with an instructor or from a boat. The more times you go through the steps, the easier it will become.
4) Scout various dive locations close to you whenever time permits. Take photos, make notes. (I keep site notes in evernote)
5) Learn to swim the four standard strokes if you don't know how, it will help your confidence immensely
6) Try to incorporate some swimming with fins into your workout routine. It will help your strength and endurance when diving.