Let’s run some simple numbers.
Your goals are rather modest, you want to net $50.000 before taxes and have $20,000 to cover benefits; you want to work 44 weeks per year.
To teach diving you need a pool. If you can get one for $50/hr you’re lucky. Ten hours per week for 44 weeks is $22,000 (maybe you should build your own pool – but that’s another topic).
To teach diving you need a classroom. If you can get one for $20/hr you’re lucky. Ten hours per week for 44 weeks is $8,800 (maybe you should build your own classroom – but that’s another topic).
To teach diving you need tank fills. If you can get them for $5/each you’re lucky. 44 week long courses each with eight students, each using six tanks, costs you $10,560 (maybe you should get your own compressor – but that’s another topic).
To teach diving you need gear. If your courses are 8 students you will need at least 16 sets, if not more. Each set is about $2,000 … so servicing the debt (there’s no depreciation on the gear I assume you sell it off at the end of the year for what you paid for it) is going to be about $3,000.
Dues, insurance, Con-Ed seminars, advertsing, dive shows, etc, will be about $3,000 per year.
You’ll spend $7,000 in automotive costs
Your costs are $54,360. You need to make $70,000 more to make it worthwhile, so that a required gross of $124,360.
I’m not saying that you can … but if you had 8 students per week and taught 44 classes (that’s 352 students), you’d have to charge a bit above $350.00 plus certs and materials to meet your goals.
BTW: The “magic number” for a dive shop to stay alive is often said to be 300 new students per year.
If you disagree with my numbers, or your expectations are different, or your projections are different, that's fine ... in fact that's great ... plug in your own values and share your conclusions.