The propeller of a boat can do major damage to a diver on his way back up to the surface. It is therefore important that you review the ascension procedures that will keep you safe from passing watercraft. Consider the following tips:
Begin your ascension early Keep in mind that in order to ascend properly you will need to take your time. As such, begin by taking note of how much air you have left, how tired or cold you feel, and the no-decompression limit as well. It is important to start your ascension while you are still fresh.Ascend Slowly
Dont go any faster than 30 feet a minute. Be sure to also begin orienting yourself as you go up. Consider where you are currently located in light of where you plan to surface at. You also want to note the conditions around and above you including the choppiness of calmness of the waters, boat traffic and other divers as well.
Use your Dive Flag Buoy This is something that your divemaster
should carry especially if you are diving in a place with lots of boat traffic. It should precede you to the surface so that watercraft can know just where you are under the water. You should surface as close to the buoy as possible. If you do not have a dive master with you, you should definitely do the same.
Make a Safety Stop If you have been diving at more than 33 feet, it is recommended that you stop at about 15 feet for a period of about 3 minutes. This is a great time to scan for watercraft and to listen for any propellers since you are more likely to hear them before you actually see them.
Breaking the Surface of the Water Once you are done with the safety stop, it is important for you to become buoyant prior to ascending further. You want to make sure that you are neutrally buoyant the entire time. Go up very slowly scanning the surface as you go. Be sure to turn 360° as you go. It is recommended that you take hold of the low pressure inflator in order to dump air out of the BCD if needed. In the event that you notice any boat traffic, delay the ascent until the surface is clear. However, you may also choose to swim to a different location, if you have enough air, and break the surface there.
Ascend Close to the buoy or boat come up as close to these as possible since any other boats will generally keep a respectful distance