 Captained by Commander Geoffrey Layton , her post @-@ completion trials lasted for five months as she was used to evaluate steam power for submarine use . Much was learned about the operation of steam submarines , which helped the subsequent design of the steam @-@ powered K @-@ class fleet submarines . She proved to be very unstable while surfacing , presumably because she could not pump the water out of her controlled free @-@ flooding spaces quickly enough in the upper part of her double hull . These problems , coupled with the fact that she was too slow to work with the fleet as originally envisioned , meant that she was impossible to make into an effective warship , and she was laid up after her trials . 
