has any one tried hooking 2 deep cycle batteries in parallel to increase their amp output? is this ok?any ideas out there?

What are trying to do? What are you going to hook up to those batteries?

a am trying to hook my 12 volt trolling motor up to the batteries.i have a 14 ft jon boat that iam rigging up,dou have info on the way to do it right, do i need a inline fuse?

Hooking 2 batteries in parallel will double you amp. hrs. If you connect in parallel 2, 12volt, 60 amp. hr. batteries you will have a 12 Volt, 120amp. hrs. doubling your running time. Hook them in series and you have 24 volts and quite likley a lot of smoke.

I would not go to the expense of 2 batteries. You do not need the extra weight & one deep cycle Battery will do the job for you. What Whittler said is true you just gain time. ! Battery fully charged will last you all day & then some.

It will work as they have said.  It would be better if both batteries are the same, age (condition) if one is weaker it can shorten the life of the second.  You may encounter some chargeing problem.  I haven't noticed that I get alot better results doing that in a normal day, if your battery is in good shape. I usually just carry a second battery or a small ac/dc generator if gone for a long period of time and cannot access electricity to recharge them.  I would use a switch to isolate them, I think you will have better luck.