Is there a lot of difference in castability in going  from 8 to 10 pound? I know that is not much of an increase but I do a lot of shore fishing and one particular place I fish I throw crankbaits where there are logs left there when the dam was constructed and I lose a lot of lures on them.

I thought a heavier line might help free them but it is a pretty good cast to get the lure there and I catch nice bass off those logs.  ??? I use only 8lb test.

Depends on line diameter. If you go with a thin diameter line, your 10lb line may be as thin as 6lb so your casting ability will be enhanced over say a thicker diameter line

I don't think going from 8 to 10 will help much with logs, but here are some proven things to try (in order from the simplest to the most involved).

1)  When you feel the bait hang up, STOP PULLING and try to let it float free.

2)  Apply light tension and shake the rod tip.

3)  Pull the rod tip up over your head to apply light tension and pluck the line like a bow string several times.

4)  Make a plug knocker.  This is accomplished by securing a large snap swivel to a heavy weight such as an old spark plug, a large bell sinker (1.5-2oz), etc.  Snap the weight onto your line and raise the line to as close to vertical as possible.  When the weight hits your bait, it will usually knock it free.  If not, again apply light pressure and shake.  If this fails, you are out the bait and the plug knocker, but at least you tried

Ceph, your first three suggestions sound pretty good, but the plug-knocker is very unlikely to help, but it's worth a try. I fish a lot from shore at a canal which has wall-to-wall crankbait-eating rocks.

I tried a similar commercial product and it was worthless to me. It was obvious that these things work best from a boat where you can get directly above the bait.

I then bought a pole that telescopes out to 20' and that has saved me about $200 already, but that's only because I determined before I bought it that the vast majority of the snags were within 20'.

His bait would be too far away for a pole.

Try power pro braided line.

there 30# test is a 8# mono diameter

The bow and arrow trick is very effective. Rick Clunn and michael icanelli use it. I know that if you can get the bait to release by using this proven method that you can sometimes get bit. The only real thing that I can see differ between 10lb and 8lb is the depth your crank will run. You'll probably lose about 6" on your depth. Also learn how your crank feels and how it bumps off of objects. That will enable you to feel the differnce between a snag and a fish. plus when cranking you don't really have to set the hook.

You're probably right, Marty.  I usually fish from a boat and the plug knocker works absolutely great.  I usually save a crankbait or two nearly every trip.  I have tried it from the bank a few times, though and it didn't work.  I was just trying to exhaust all possibilities for him.  If the plug knocker fails, you aren't out much, if any, cash.  Especially when compared to the cost of crankbaits.  

It also doesn't work when I decide to go "tree fishing" (but, of course pros like us would never do that) ;D