Shipwreck survival

[Vynticator]

What kinds of skills (and penalties to those skills) would a party face if shipwrecked on a cold, exposed coastline with absolutely no equipment or clothing?

Fishing.
Survival - Beach is an obvious one. But what penalties would accrue for the following:
1) unfamiliar coastline/flora/fauna
2) total lack of equipment

Perhaps different penalties for different aspects of Survival skill? After all, it covers:
-Finding food
-Finding fresh water
-Building improvised shelter
-An 'eye for country'
-Trapping wild animals

I'd have thought -5 for building shelter without *any* equipment. Seem fair?
No penalty for finding shellfish and berries (presumably, equipment-free)
No penalty for finding fresh water (no equipment needed)
-3 perhaps for trapping without rope, hammer, hooks, etc to build a snare? Or is that too harsh?

I'm thinking there will likely be penalties to IQ and DX from accrued fatigue after the swim to shore in icy waters. Also from lack of sleep over time if shelter not found quickly.

I'd really welcome other ideas on this - I want this to be a tough, gritty 'out of the comfort zone' challenge for otherwise very robust, supernormal-warrior-type characters.