  Marine vehicles have been used for various scientific missions where
information over features of interest is collected. In order to maximise
efficiency in collecting information over a large search space, we should be
able to deploy a large number of autonomous vehicles that make a decision based
on the latest understanding of the target feature in the environment. In our
previous work, we have presented a hierarchical framework for the multi-vessel
multi-float (MVMF) problem where surface vessels drop and pick up underactuated
floats in a time-minimal way. In this paper, we present the field trial results
using the framework with a number of drifters and floats. We discovered a
number of important aspects that need to be considered in the proposed
framework, and present the potential approaches to address the challenges.
