Shield tactic?

[Ziggurat]

My party of lev 8 adventurers was trying to make it back to the Monastery when they ran into 9 army ants, 9 twilight bats and 6 shriekers. I ran to one of those convenient crevices and dug in for a long battle. This 4-party is a mook monk (male, I call him "Threem" because he has 3 M's), faerie ninja, elf samurai and gnome valkyrie. Normally the valk is in center and the rest in front. Since the sam gets picked on alot (no stealth), I got the bright idea of dropping the other 2 back and putting him on defense. Meanwhile, the nin could use her cane and the monk his pebbles, along with the valk's pike. The sam has AC 11 and reasonable armor for head and feet, but he started getting bit bad by the ants. Shield ability is about 21. I saw a problem ahead with the coming twilights, which generally are much harder.

I am wondering if there is such a thing as a shield defense, i.e., a way to take advantage of it tactically? My trick didn't work, I switched them back next move with much better results (killed them off almost as fast as they moved in). A second question is: how much protection do you really get from a shield?

[Scatter]

'Defend' only adds 2 to AC, regardless of shieldage. Shields add to your overall AC. Most shields can double their AC value (eg Round can be worth 2-4 AC), at 1 point per 15 Shield Skill. Light only adds 3 from skill, and not starting til 60 Skill.

[Slag]

I find shields to be pretty useful for some classes, using a good shield will get you a "hits SHIELD" message quite a lot. They're perfect for bishops, bards, gadgeteers and other casters too, anyone with a small amount of hit points. I don't give them to fighting classes though, as a 2 handed weapon or good offhander is more useful there.

[babar]

sure, I've done that before. same type situation except 6 chars. lord and sam in front, in a crevice, defending, while those behind wail away, with a stragetically placed heal now and then. it's a lot harder to keep them alive if they are fighting (plus lose stamina and could faint).

[Ziggurat]

Yeah, I was worried about running out of gas (as well as the damage). It was a bit early in the game for 24 vs. four hybrids.

[ferro287]

Scatter, there are a couple of errors in your post: Defend definitely adds points to your shieldage. I don't know at which shield skill it starts, but it's a maximum of +2ac (added to the +2 from defending)
Light shield gets +1ac at each 25/50/75/100 so it maxes at +4ac, which gives +6ac when defending (that's the way the engine tells you: +10ac shield, +6ac from shield skill, just when defending +4ac from shield skill otherwise).
Iirc (I'll try to check) those skill values (25/50 etc) go for the other shield as well, capped at the ac for the shield in question (so you need 75 to get the +3 for the kite, etc.)

[Scatter]

oh. I guess i haven't been that exacting; i usually don't use a shield after i've gotten Stealth, and during Stealth training (while Defending), i usually get a point more attributed to Shield at 15, 30, 45, etc. but never more than double the shield's original value. Maybe the Skill you need for more AC goes down when defending. I've only kept Light Shield a couple times, and i know it's different, but i didn't play with it much, and nobody who had it had less than 90 Shield.