Seal The Lid..
I sell shrimp for a living (dont laugh I made $54K last year) and carry it in 10# bags in a 120 qt Igloo coolers..the problem I ran into when I first began was that the coolers sat in the back of my truck all day and were blasted by the wind when I drove.Ice went fast..Upon examination of the coolers during the day it was obvious the ice was melting around the areas where wind intruded fastest.I hit a Home Depot and got some door trim weather stripping and sealed the lids..now ice lasts several days..not several hours.The coolers I use are the best Igloo makes as far as insulation goes..but are too big for use on a boat or even for one person to move once loaded.On my boat,there is a big built in ice box..it makes for a good storage bin,nothing more.Ice in there lasts only a short time.I use a small (50 qt) Igloo cooler with a gasket around the lid..freeze several bottles of bottled water and put one in each corner of the cooler then put in your drinks..use CUBE ICE over everything (not the ground up stuff-it melts too fast).This set-up has cold drinks in my cooler for about 7-9 days.As for who makes the best coolers..PracSailor can say whet they want..I make my living with these things and have handles Coleman,Rubbermaid (JUNK)Igloo,etc..and I swear by Igloo.You can get parts almost anywhere for them (not so with Coleman and most other brands) and they hold up well under the sun..something P/Sailor did'nt test..but I have.Igloo number 1..Coleman behind in 2nd place.NOW,if you wanna spend hundreds of dollars....then you get into another place..but for $20.00 or less you can have a cooler that'll likely last as long as you own the boat and do a good job for you..hit your local Academy store and look around..you'll find what you need there..and it'll say "Igloo" on it (LOL). Fair Winds>>> David