Those pocket snorkels are crap. Way to flexible and not enough length to keep the top out of the water in any sort of chop.
Like everyone else, I was required to wear a snorkel during training, found countless posts on here about others not wearing a snorkel. The typical line is "You're scuba diving, you don't need a snorkel." Which is partly true... Until you need it. I had an incident where I needed it and left it at home. I wish I had my snorkel then.
Fortunately there are good solutions out there. For the snorkel, I looked at what freedivers are using. Consequently I found the best snorkel I've ever owned and perfect for scuba. The Riffe Stable Snorkel.
SNORKELS A little pricey, but well designed.
Many snorkels have the big water collector at the bottom which adds another 2-3 inches to the length of the snorkel and it makes it bulky and cumbersome, especially by your face. The Stable has a wide collector which is much more streamlined and a noticeably different experience. It has a purge valve and the top is designed to keep splashing water out. It doesn't have a stupid flopper valve that only inhibits breathing. On my snorkel I removed the mask clip and replaced it with a figure 8 holder.
Part of the key to snorkels and scuba is where the snorkel is positioned. Many people leave the snorkel positioned at the point where the mask and strap connect. This is incorrect. The snorkel should be back further behind your ear. When you're face down in the water with the snorkel in that position it will be straight out of the water. Having it in the correct position also allows you to stow it properly during a dive which results in it being completely out of the way and nearly unnoticeable. You can either turn the snorkel backwards or pull it down tucked by your neck under your chin. The key here is the rubber figure 8 snorkel holder because it grips the snorkel and prevents it from twisting and turning. Also, the Stable snorkel's design is perfect for this because it's not a cylindrical tube. It's more of a tear drop shape like the wing of a plane. That design prevent the snorkel from turning during a dive and having the mouth piece bumping around your face.
Anyway, I know this thread started with training standards, but I'm an advocate of using a snorkel in the ocean and hopefully this post helps anyone looking to solve the snorkel issue.