What use of social networking for a scuba diving equipment niche can be effective?

What I want to do is sell scuba diving equipment. I could consider getting into promotion of vacations related to scuba diving. As I go along and get some kind of traffic I am sure to come up with new directions to follow with my website. Maybe I will create some new sites and/or promote WA.
To date my posts describe and discuss and review equipment. I am promoting some more technical equipment and have one post related to wreck salvage and will do more related to commercial diving, gold dredging and salvage that are not just discussions of equipment, but involve a little history and story telling. I would like to generate commentary from readers, but I suspect it is not a subject that will develop a lot of feedback.
As required by the training here I am enrolled on Facebook, twitter, google+ and pinterest. I have lived in Asia for the last 32 years. A lot of the time I did not have internet access and there was a stretch in the 90s in the Philippines with no telephone or TV (or electricity or clean water) and recently with google, Facebook and others blocked here in China. Until the last couple of years there wasn't a reliable vpn available here. The point of this history recitation is that I do not have a big historical social network to draw upon. There are social platforms in China that are very effective here, but are heavily monitored by the government. I am leaving China in another month and don't plan to maintain contact with people here.
Facebook doesn't seem like a platform to share my website with. Sharing there just seems like spamming. I suppose it is the same with google+. I can easily generate followers at pinterest. It remains to be seen if traffic will come from that, but I feel somewhat hopeful there. At twitter, generating followers is slow going, and again what I write about regarding diving just doesn't seem to be a subject for that platform. Of all the people who have emailed me at all my addresses over the years, not one is on twitter.
Where is my thinking and approach right or wrong? I'd welcome any ideas.
Thanks.
Just an idea. Hope this may help. For a more exciting diving, you can also site examples and introduce new gadgets that they can explore.
Your friend HAP 33
Regards
Wildgeese or Steve
The same experience with me to use vpn in China, but now I have a reliable VPN with stable IP service. it is not convenient to work with social media marketing without vpn. if you write article blog with content that followers interest in, you are easily to get more traffic with website and social media,pinterest, instagram,facebook,twittter is great source to promote scuba diving themes. but more of the divers will be more interest in underwater creatures and ocean life conservation, you would like to write something with this hot topic.I will write some articles about how to get more traffic with instagram,twitter, facebook and pinterest.
Try Facebook and Instagram. Facebook & Instagram Business Marketing 201 by TonyHamilton Instagram 101: Posts and Reposts with Canva, Part 1 by jetrbby80316
There are lots of tutorials here for them.
Monica