How many hours can you last on a kayak?

I started out on average about 4 hours at a time on the kayak but lately I've stayed out for as long as 6 hours. How long do you/can you last fishing on a kayak?

Really depends on the wind. I usually stay out about 6 - 8 hours if conditions are perfect.

I've also noticed an inverse correlation between trip duration and catch rate...

It depends on the conditions. If there's a steep swell and wind chop, then 5 hours can seem like a long, long time. When conditions are nice I could last a lot longer, but rarely go much beyond 6 hours, as by then I've either found what I was looking for, or I'm getting bored out of gourd...

For my guided trips 4 hours is the minimum we should get to fish.  6 to 7 is average, and 8 is pretty common.  Sometimes we stay for up to 10 if the water's really nice, but not if I am fishing the next day.

The problems for me come on my "day off" from guiding.  I am usually pretty laid back, but I get sucked in to trying to drum up some nice catches for marketing purposes.  Spent more than 10 hours a couple weeks ago and it was quite a burn.  Good problem to have.   

Being out in a strong current or wind usually limits a trip to 6 hours, but a bite late in the session can change all of that and keep you at it.

Paddling a yak is basically like walking - you need to be able to do it all day if you want to do well at the sport.  Sometimes you need to 'jog' and sometimes you need to 'sprint' for a bit - you always need to be able to keep paddling.

Or Peddling!!!! Everyone and every kayak has it's comfort level. Start where you are and work up to longer. Like any sport... Training on and off the water pays big when you are out there playing! 

Or Peddling!!!! Everyone and every kayak has it's comfort level. Start where you are and work up to longer. Like any sport... Training on and off the water pays big when you are out there playing! 

Yes this is very true... Used to be 6-8hrs max but after the Hobie & new seats, I’ve been pulling lots of 10-14hrs a day (Darn to Dusk). I hate dark, so don’t like to stay late but some fishing can be really good on dusk.
As long as I have the fluids & some snacks, the limiting factors are fishing (although I tend to stay out there longer if I don’t catch fish), weather, daylight or WAF nowadays...

salmon/halibut trolling 5 hours is my max, rockfish can go long, sturgeon virtually never tired, but my average is shy of 5 hours on the water. that is about 4 hours of fishing. not that I cant go longer, just nice to get out early and have half of the day to do other stuff without feeling exhausted.

Wind/swell notwithstanding, for me I usually cut the day off earlier in order to err on the side of my energy stores for landing and shlepping all the gear back to the car. This is for the more rugged beach launches with trails to the water. I'd guess 6 hours is tops OTW.

For someplace with more 'civilized" accommodations like close parking to the launch site and a protected launch (like a harbor or Shelter Cove)I'll stay out longer because the landing and loading is a lot easier.

Freshwater? Often around 14 hours in the summer in the sierras, from 5-6am to 9pm..

In the ocean I can only handle 4-6 hours, its just exhausting keeping an eye on everything that is going on (swells, that stupid seal that pops up and spooks the shit out of me) and I end up getting seasick. On calm days I can stay out all day but am usually done with my rf limit by then.  long days of salmon trolling can get a bit monotonous if nothing is biting.

depends on the conditions and the kayak. But If I am on the Predator PDL I have spent up to 8hrs. The seat is where it all matters

6 hours - that's when my SS battery is done,  but even before I had one, a nap starts to sound better and better after 5 hours.  Now, if I was 40 years younger....

Four to five hours. If I haven't caught what I want by then another day awaits. Also, as Tom says, getting up there in years makes naps more attractive and enough energy has to be kept in reserve for beach landing and hauling yak and gear to the car.

14 hrs twice are my longest days, but I have done 12 hours many times too.

Not exactly apples to apples as I'm a spearo that dives from a yak, but I consistently put in 7 hour days if conditions are good or the fish are limited.

Often depends on what type of breakfast was eaten.  Bowl of cereal all day ,breakfast burrito with chorizo maybe 4 hours . Late night of drinking and Andy Morales cooking 2 hours top.