Sorcery: Breathe Water

Artist's Site

I like utility spells. I'm in between series concepts, and I have a bit of writer's block. So let's take a look at creating a simple spell, Breathe Water. The vanilla version of this spell is on p. 189 of GURPS Magic. How would it look like as a power?

So, breathing underwater is basically Doesn't Breathe (Gills) plus we need to add in mana sensitive. Very simple.
Breathe Water Buff (-60%): Doesn't Breathe (Mana Sensitive, -10%; Gills, -50%) [8]
This will be a buff that lasts for three minutes at least. So we need to afflict someone with this advantage for three minutes and the affliction needs to have the Sorcery modifier.

Breathe Water (+80%): Affliction(Sorcery -15%; Advantage, Breathe Water Buff +80%; Increased 1/2D, 10x, +15%; Fixed Duration, 3 Minutes, +0%) [18]

So this spell costs 1 energy and requires a roll against an innate attack skill to work. It lasts for 3 minutes.

Other Notes

A version of the spell for an item enchantment would be the Breathe Water Buff spell as statted, but Mana Sensitive exchanged with Sorcery, making the entire cost [7] instead. An enchanted item would allow a user to breathe for 1 minute per every point of energy expended, but the ability to give other people the ability to breathe underwater would be lost. The Breathe Water spell with the more common -10% power modifier would have an unchanged cost of 18 points, for example, to use as a Psionic Power or Prayer.