Here's a sample write-up of a level 4 standard complication. This is more of a PC vs. environment encounter than a social encounter. While I went with a variant approach for the way in which Nature and Perception checks accumulate successes, partly to show off another possible twist for skill complications and partly because it seems to me that all the Nature and Perception in the world isn't going to help if nobody rows the boat, the level of challenge wouldn't change very much if each successful use of the skills earned one success as normal.
Rowing a Leaky Boat to Shore
Level 4 Standard Complication (XP 350)
Setup
The PCs are in a leaky boat in rough waters. Perhaps they are on a lifeboat escaping a sinking ship, or their boat hit a rock while they were navigating some rapids. The PCs must row the boat to shore before it sinks.
Progress Phase
The PCs overcome the complication once they have earned 8 successes.
Primary Skills
Athletics: On a successful DC 18 Athletics check, the PC rows the boat closer to shore. This counts as one success.
Arcana: A PC with the mage hand cantrip may make an Arcana check in place of an Athletics check.
Nature: The PC uses his knowledge of water currents to pick out the easiest path to shore. On a successful DC 18 Nature check, the next successful Athletics check earns the party an additional success. This stacks with the benefit for Perception (see below).
Perception: The PC locates the most direct path to shore. On a successful DC 18 Perception check, the next successful Athletics check earns the party an additional success. This stacks with the benefit for Nature (see above).
Bonus Skills
Religion: A PC who worships a deity with an appropriate portfolio (e.g. nature, water or sailors) may offer a prayer to his god for assistance. On a successful DC 18 Religion check, the party earns one success. This skill can be used only once in this way during the encounter.
Recovery Skills
Arcana: A PC who knows the make whole ritual may recite a simple incantation that temporarily plugs the holes in the boat. On a successful DC 22 Arcana check, the party does not accumulate a failure in the complications phase.
Endurance: A PC may bail water out of the boat fast enough to negate one failure with a successful DC 22 Endurance check.
Complications Phase
The PCs fail the complication once they have accumulated 8 failures. Both of the following occur during the complications phase:
Slow Sinking
The boat takes on more water. The party automatically accumulates one failure.
Unstable Footing
A randomly selected PC must make a successful DC 18 Acrobatics check or lose his balance and be unable to act during the next progress phase. (Note: if you prefer to have the complication roll against the PC's passive Acrobatics skill, use 1d20+7 vs. 10 + PC's Acrobatics modifier).
Failure
The boat sinks (8 - number of successes earned by the PCs) x 5 squares from shore. The PCs have to make Athletics checks to avoid drowning and to swim the rest of the way.
Upgrade to Major Complication
Increase the number of successes required by the PCs to 12, and the PCs fail once they have accumulated 6 failures. If the PCs fail, the boat sinks (12 - number of successes earned by the PCs) x 5 squares from shore. Increase XP award to 875 XP.