Most often, 30 foot dives will take place in open water. There are some dive training centers with dive pools that may be deep enough. If you are planning to free dive (hold your breath at surface, dive, and return), you can go out into open water and try some free diving, shallow at first. Do not do this without a swim/dive buddy. If you want to dive Scuba, you'll need to get certified first to avoid killing yourself. When ascending after breathing air under pressure, you'll need to do it properly. Free dive or SCUBA dive, I would never recommend diving without a swim/dive buddy with you.
They can dive up to 500 feet deep.
Orcas can dive upto a 1,000 feet (304.8m).
Walruses can dive to depths of about 80 to 100 meters (approximately 260 to 330 feet). They typically dive for food, such as clams and other benthic organisms, and can hold their breath for up to 30 minutes while underwater. However, most of their dives are shallower, generally around 20 to 30 meters (65 to 100 feet).
All military submarines dive into deep water. The deeper they can cruise,the harder they are to find. I call 'deep' any more than 120 feet down, but most modern military submarines can operate as deep as 900 feet, many even to 1500 and possibly more. There are now many civilian submarines (shallow divers) which show tourists the undersea reefs and fish life. These generally operate between 30 and 90 feet down and I doubt that any could safely dive deeper than 200 feet at most.
Up to 100 meters which is over 300 feet deep.
No, the recreational dive limit is 130 feet. However, with the right breathing equipment and suit, much greater depths can be achieved.
30 fathoms is 180 feet.
it can live to about 5,000 feet down deep in the water
Narwhals prefer to be near the surface, but can dive as deep as 5,000 feet.
The blue whale can dive for 10-20 minutes and dive for 500 metres deep.
30 inch's of water how deep
The time it takes for deep-sea divers to surface can vary significantly based on their depth and the type of dive. Typically, a diver may ascend at a rate of about 30 feet (9 meters) per minute, but they often need to include safety stops to avoid decompression sickness, especially if they have been deep diving. As a result, a dive from 100 feet (30 meters) could take around 10-15 minutes to safely return to the surface, including stops. Always, the specific ascent time will depend on the dive profile and safety protocols followed.