I have seen many people get slammed and fall off the ladder when they try to climb it very quickly. Most people (who really need help with this) are NOT particularly strong and can not scramble up a ladder, after being tired and while wearing 75 lbs of gear. Women, with their reduced arm strength are at a relative disadvantage too.
MY advice was always to watch the ladder for a few moments. Try to understand the timing of it. When the ladder is going down, you need to grab the top and slam your feet down on the lower or bottom rung. Then STAND UP! That is the most important part, get your weight on your feet with your knees locked! People can not hang on a ladder with their arms strength, they will get striped off when the ladder lifts them and they will smash their chin on the ladder.
So.. grab the ladder and stand up as it is going down. Stand on it as it lifts you up.. THEN, when the ladder goes down again, you should try to take a step or two up the ladder as you are partially submerged. Being partially submerged, provides some buoyancy and makes it easier to climb... but again.. climb with your weight on your legs.
Take your time climbing, if it takes a few cycles of up and down to get up the ladder that is fine. Trying to rush and scramble up the ladder will make you fall, plus if you try to climb as it is lifting you, the inertia makes you heavier.
Also if you miss the initial grab on the ladder, back off for a moment and try to time the rhythm again. Sometimes you have to kinda make the grab totally blind because the ladder is going up and down in white foam and bubbles. Keep your arms outstretched, so the ladder can't come down on your head and kill you.
Also, this is important, if you begin to fall from the ladder, allow yourself to fall back into the water on your back. Struggling to hang on after you have lost your footing or a good hand hold can damage your shoulder, cause you to split your chin or worse.
Take your time to mount the ladder, STAND on the ladder before you climb and go slow.