proposal for change of subs in default ruleset

I propose the following changes to submarines. Speak up now if you think
this is a bad idea.

  - Per

Index: data/default/units.ruleset
===================================================================
RCS file: /home/freeciv/CVS/freeciv/data/default/units.ruleset,v
retrieving revision 1.39
diff -u -r1.39 units.ruleset
--- data/default/units.ruleset	2002/09/19 14:16:31	1.39
+++ data/default/units.ruleset	2002/09/23 19:24:25
@@ -1360,7 +1360,7 @@
 [unit_submarine]
 name          = _("Submarine")
 move_type     = "Sea"
-tech_req      = "Combustion"
+tech_req      = "Steel"
 obsolete_by   = "None"
 graphic       = "u.submarine"
 graphic_alt   = "-"
@@ -1368,25 +1368,25 @@
 sound_move_alt = "m_generic"
 sound_fight   = "f_submarine"
 sound_fight_alt = "f_generic"
-build_cost    = 60
+build_cost    = 50
 pop_cost      = 0
-attack        = 10
+attack        = 15
 defense       = 2
 hitpoints     = 30
 firepower     = 2
-move_rate     = 3
+move_rate     = 5
 vision_range  = 2
 transport_cap = 8
 fuel          = 0
 uk_happy      = 1
-uk_shield     = 1
+uk_shield     = 0
 uk_food       = 0
 uk_gold       = 0