Brewer Expedition
August 10 - August 17, 2006

August 16, 2006
ROV Dive 5: The Clathrate Bucket

Yesterday, after our ROV dive, the Western Flyer steamed northward to a secondary site for another attempt at an AUV launch. Despite increasingly rough seas, the AUV launch and recovery went remarkably smoothly and produced some valuable underwater mapping data. Hopefully, we will have a repeat tonight of last night’s success.

This morning, after traveling back to the original hydrate outcrop site, the ROV was prepared for the day’s dive. A “clathrate bucket” was installed onto the robot’s swing arm for the purpose of collecting and preserving hydrate samples for later laboratory study. The intention was to collect two core samples from both the harder, higher oil-concentration zone of the hydrate outcrop as well as two samples from the softer, purer zone of hydrates.

By the end of the day, we were successful in this endeavor, although the purer samples appeared to be softer than initially predicted. In addition, we were also able to make occasional observations of the samples at the elevator frame – the dissociating time-lapse camera sample and the carbon dioxide exchange sample. Finally, we were successful in using a heated funnel mechanism that was able to dissociate both an oil-saturated and pure hydrate sample into their component gas forms and preserve them in pressurized containers for retrieval.

Tomorrow will be our last dive, in which we will examine both samples resting on the elevator frame with the PUP (Precision Underwater Positioner) attachment for the DORISS laser optic probe head.

The hardest part of an AUV dive is actually its retrieval, which requires a small craft to tow it into the range of the ship’s crane.

The heating funnel was successful in releasing the trapped gas from the hydrates.

The time-lapse camera will continue taking pictures of the two dissociating cores for approximately 48 hours.

[Previous Day]    [Next Day]