Tampons should be changed every 4-6 hours.
Some tampon manufacturers say up to 8 hours - this time-frame was introduced after the TSS outbreaks in the 1970's-80's, but modern understanding of tampon risks say that this is too long to leave a tampon. The longer tampons are left the longer you are allowing bacteria to multiply (they do so exponentially) and preventing vaginal cleaning, if you can go 8 hours without leaking it also means you're using too high an absorbency which also increases TSS risks.
Tampon companies continue to say 8 hours maximum to make their products seem more convenient, as they are self-regulated they can say this regardless of the risks.
You cannot do this, it would be embarrassing for you, so wear a tampon, or stay out of the pool.
Hippo can stay in water for 16 hours
16 hours
It depends on her individual needs. Tampons need to be changed at least every 4-6 hours, or sooner if the tampon leaks before then - women should also alternate with pads as often as possible, or at very least use pads overnight rather than tampons.
8 hours.
For about 3 hours.
Forever
There is no way that you would be expected to sit on a boat for 15 hours without any access to a toilet - it just wouldn't happen, if you have access to a toilet then you can change your tampon and pads. If you are ever in a situation where you can't change a tampon every 4-6 hours then you shouldn't use a tampon, you can leave menstrual cups or softcups in for up to 12 hours so could potentially go a little longer without risk.
A dog can stay without peeing for max of 4 and a half hours
There are many places where one can learn how to insert a tampon. One can learn how to insert a tampon at popular on the web sources such as YouTube and Playtex Sport.
Your tampon should be completely saturated with blood after 4-6 hours - if the tampon is dry when removing then you need to use a lower absorbency or switch to pads. If the string is getting blood on it some may be from blood lingering in the vaginal canal before tampon insertion, but it may also be that blood is simply bypassing the tampon. Try different TYPES (not just brands) of tampon, you may also want to consider menstrual cups which don't leak.
That varied from mission to mission.