I hate to say this, but it honestly depends on the TSA agent you get. Some are tougher than others, and if s/he decides it can't go, it can't go. Period. There is no arguing with them at all. So, be prepared to toss out whatever they decide you need to toss. LOL.
As for the size of your carry on, and what is permitted, read the rules of the airline CAREFULLY. They are not all the same. Some go by overall size, and some have specific dimensions you must meet in each direction (height, width, depth). Not every airline is the same. There is no problem carrying snorkel equipment IF it fits within a bag of the proper dimensions.
Even if your bag meets the requirements, there is ALWAYS the possibility that the airline will require you to check it because of space limitations on the specific plane you board. And, remember, carryon bags are always supposed to be of proper dimension/size to fit under the seat in front of you....airlines consider this space to be your primary storage space. The bag you describe in your OP is not going to fit under the seat in front of you, and would be at substantial risk of being booted into the luggage hold for that reason.
But, read the airlines rules and make sure you follow them.
As for the size of your carry on, and what is permitted, read the rules of the airline CAREFULLY. They are not all the same. Some go by overall size, and some have specific dimensions you must meet in each direction (height, width, depth). Not every airline is the same. There is no problem carrying snorkel equipment IF it fits within a bag of the proper dimensions.
Even if your bag meets the requirements, there is ALWAYS the possibility that the airline will require you to check it because of space limitations on the specific plane you board. And, remember, carryon bags are always supposed to be of proper dimension/size to fit under the seat in front of you....airlines consider this space to be your primary storage space. The bag you describe in your OP is not going to fit under the seat in front of you, and would be at substantial risk of being booted into the luggage hold for that reason.
But, read the airlines rules and make sure you follow them.
