ive got a Bass pro brand 2 bank charger(made by promariner) i need to put my batteries up front for better performance but have nowhere for the charger up front so its in back the original cables aren't long enough i didn't wanna have to order 2 of there extension cables if i can just snipe em splice em with some marine wire ive read the book and the only thing it says is not to shorten them because of the in line fuses any insights it doest say anything about special wire besides the fuse and doesn't seem to be shielded or anything any thoughts

Consider mounting the 2-bank charger in the same space as the 2 batteries, or an adjacent storage space.  That's what I did with my Fisher.  I have 2 batteries in the bow storage area, to power the TM.  When I want to charge them, I simply unplug the TM and the FF, and plug in the charger to an extension cord that comes from my garage.

Just remember to unplug the extension cord when it's time to move the boat!!!

Cal

well i just talked to pro mariner and since there extensions wouldn't work anyway because the way they hookup with a screw and nut i wouldn't be able to fit 4 in my wire channel they told me to cut at the connector and splice 10 gauge run to where i need and and a 40 amp blade fuse to each lead and i should be good

I did the same thing only with 8 gauge.  My center console has no place for a charger and limited space for my 2 TM batteries.  I have a dual pro and they even sell extensions as accessories.  You wouldn't want to go real far with them, but extending them some won't hurt.  I lengthened my cords by probably 7 ft and have not had any problems.  I didn't add any extra fusing.