My thoughts would be to add a small outboard
mount for it, a couple of solar panels
and a small gas generator
(say a small honda
1k, the really quiet model, this will get you back to Portugal
. Also make sure the boat has a good light air sail like a drifter/code0/asymetrical so you don't need to use the motor
That size of motor should keep you going at about 4kt (100nm/day) on a boat that size, and fairly efficiently too.
and cost issues aside the only hard part I see is mounting the motor given the highly raked transom. From the photos I found on AllBoats.com could probably attach part of the motor mount to the liferaft
support frame at the transom.