Cruise Planning

Shipboard Operations and Cruise Planning

Advance information is vital to planning a successful cruise, particularly when deploying large and complex oceanographic equipment.   Information on HMRG shipboard operations, support vessel requirements, personnel requirements; data collection and processing policies and products are provided.

 

HMRG Shipboard Operations

The following provides a description of equipment and systems needed for HMRG operations. These requirements are intended as guidelines for cruise planning and selection of a vessel suitable for offshore operations.   University-National Oceanographic Laboratory System (UNOLS) Global Class (> 200 ft.) and Ocean/Intermediate Class (150-200 ft) vessels are routinely used for HMRG operations; non-UNOLS vessels must meet UNOLS safety standards and be approved by SOEST administration.

Shipping Container The vessel must provide space for one 20’ x 8’ x 8’ (8 x 2.4 x 2.4 m) ISO shipping container (van), containing all the sonar equipment, depressor weight, and supplies, that are necessary for a cruise. The container weighs approximately 15,000 pounds (6,800 kg). The container must be welded (or bolted) and chained to the deck; the total area required is 740 ft2 (69 m2).   If more than one sonar is required for the mission, space for a 2nd container may also be needed.

Real-time displays and winch controls are monitored continuously by fish flyers and sonar engineers.

Deep Sea Survey Winch:  The MR1 has a dedicated launcher, cable, and winch; a description of configuration for this system can be found in the MR1 Launch and Recovery section.  For IMI30 and IMI120 operations on UNOLS vessels, winches, traction units, and cables are usually supplied by the vessel operator and/or are acquired from the National Science Foundation’s (NSF) winch and wire pools. For other vessels, HMRG will work with the client to specify and acquire the winch and wire and to assure that they can be safely deployed on the ship being used.  Winch and overboarding sheave(s) must comply with UNOLS Safe Working Load Standards Appendix A.  A typical winch assembly is usually mounted on the centerline near the stern of the vessel and includes the following components:

Weight Size (L x W x H)
Traction Unit 22,000 lb (10,000 kg) 12’x7’x12’ (3.4×2.1×3.4 m)
Level Wind 2,900 lb. (1315 kg) 8’x 4.5’x 6’ (2.4×1.4×1.8 m)
Storage Drum 30,800 lb. (14,000 kg) 8’x 7.5’x7’ (2.4×2.3×2.1 m)
Diesel Power Pack 7,500 lb. (3401 kg) 11’x 4’x7’ (3.3×1.2×2.1 m)

Tow Cable: Both the IMI120 and the IMI30 require electro-optical (fiber-optic) tow cable such as Rochester A302351.  Both systems can be operated to depths of 6000 m, which requires 10,000 m or more of electro-optical cable; shallower surveys can be accomplished with shorter cables.  Typical electro-optical cable has a weight in seawater of 608 lbs/kft or 905 kg/km.

Support Vessel Requirements

Deck Configuration: MR1 deck configuration is unique to that sonar system and is discussed in the MR1 Launch and Recovery section. To support the IMI120 and IMI30 systems, the ship must be capable of handling a tow cable over the side. Typical overboarding of this wire is done from a sheave mounted to either an A-frame or suitable crane. Tow point locations at the stern (on or near centerline) or amidships over the side have been used. A tow point must be at least 10 ft (3 m) outboard and 10 ft (3 m) above the deck plane. Tow points must also be capable of supporting a maximum wire load of at least 22,000 lb (10,000 kg). Additionally, mounting points should allow deployment and recovery of the wire from its outboard location to a point no less than 5 feet inboard. Should the candidate vessel not have sufficient overboarding capacity, an A-frame must be installed as part of the system. The ship’s deck must be capable of supporting the winch, wire and A-Frame installation.  A typical A-Frame weighs ~11,000 lbs (22,700 kg) and has a dimension of ~ 15’L x 12’W x 17’H (4.5 x 3.7 x 5.2 m) with a 10’ (3m) overboard reach.

Power Requirements:  Power requirements for the system are as follows (60 Hertz):

Voltage Amperage
Survey Winch
(if diesel is not used)
440V 3 phase 700 start (200 max. running)

Note that if the survey winch is powered by its diesel, no electrical power from the ship is needed. In this case however, diesel fuel from the ship will be required. Power pack must be filled once each day the system is operated, and tank capacity is approximately 55 gallons.

Survey lab data acquisition computers and displays require 115 VAC (± 10%, 47-63 Hz) power, up to 38 A.  Optionally HMRG can provide transformers for operation with 230 VAC power.  Survey lab space must be air conditioned and nonsmoking.  Depending on at-sea processing needs, as much as 40 m² of lab space may be needed;  HMRG can provide a 20 m² lab container if sufficient lab space is not available on the vessel.

Personnel Requirements

Hawaii Mapping Research Group (HMRG) will provide three to six individuals per cruise, depending upon the requirements and complexity of the mission.  Considerations for HMRG staffing include the following:

  • Side-scan system(s) and peripheral devices (e.g. magnetometer, sub-bottom profiler) required
  • Duration of continuous operations
  • Type of navigation being used
  • Data processing requirements and immediacy
  • Mission- or ship-specific arrangements for winch and winch operators
  • Availability and expertise of client’s personnel for support roles (e.g., fish flyer, data processor)

There are a number of roles that may be needed for any operation and, depending upon the expertise and mix of available HMRG staff and the complexity of the mission, each individual often acts in more than one role.

The HMRG Party Chief is responsible for communications with the Chief Scientist and Captain and coordinates activities among watches.  The HMRG Party Chief works with the science party to assess the quality of the collected data.

A Sonar Engineer is responsible for operation and maintenance of the side-scan systems, peripheral sensors, and cable termination.

An Operational Lead is responsible for coordination of deck operations and fish flying.

Three Fish Flyers are needed to stand 4-on/8-off watches to “fly” any deep-tow system such as IMI30 or IMI120. (Fish
flyers are not required for the shallow-towed MR1 sonar.) If available and qualified, personnel from the client’s party may be able to act as fish flyers.

The Computer and Data Processing Lead is responsible for real-time back-ups, data processing computers, data management, and coordination of data processing.

Depending upon the client’s requirements for data processing and product generation aboard ship, one to three Data Processors are needed for basic tasks such as bottom picking and bathymetric data cleaning.  They may also work with the data processing lead on more advanced tasks such as navigation corrections, chart production and final product generation.  Scientific or client-provided staff members are routinely trained as data processors.

Winch Operator(s) may or may not be needed, depending upon the ownership and set up of the winch.  On some vessels winch operators must be ship’s crew. Often the fish flyers serve as winch operators during routine fish flying, but a crew member will control winch operations during launch and recovery operations on deck.

Data Acquisition, Display, Management, and Processing

Data are collected using dedicated acquisition computers, usually located in a space near the stern of the vessel where the cable carrying the data can be most directly routed.  Optimally the winch control system can be set up near-by so that only one fish flyer/operator is needed per watch for deep-towed systems.  The fish flyers are responsible for safety of the fish and monitoring of real-time data.

Typically the MR1 system is towed at 50-100 m beneath the surface; the IMI30 at 200-800 m above the bottom; and the IMI120 at only 50-100 above the bottom; therefore IMI120 operations can be somewhat more challenging than MR1 or IMI30 operations, since risk of the fish hitting the bottom is greater.  For operations to 6000 m as much as 10,000 m of cable may be needed and up to 8000 m may be paid out; during turns cable is routinely brought in to minimize risk.

All bathymetric and sidescan data are logged and displayed on the real-time data collection computers, as well as data from peripheral systems such as magnetometers and subbottom profilers. All data are regularly transferred to processing computers and backup media (tapes and/or portable disks.)

Real-time display of IMI30 sidescan data over previously collected multibeam bathymetry data in Mariana Trench area.

HMRG’s own near-real-time gridded bathymetry and imagery display software incorporating trackline layout capabilities is made available for science party use on a dedicated computer system.  Gridded data from previous surveys can be used as a background for the real-time data, which aids in planning new lines to fill gaps or to indicate areas where higher resolution data are needed.  The ability to geographically view high-resolution bathymetric or side-scan data in near-real time also allows scientist to select sites for detailed sampling or video surveys, including dredging, coring and camera operations.    These display capabilities are also available for multibeam data display aboard SOEST and other UNOLs vessels.

This sidescan chart, although generated from an R/V Kilo Moana multibeam dataset, is a typical product available for data from all towed HMRG systems.

This bathymetry chart, although generated from an R/V Kilo Moana multibeam dataset, is a typical product available for data from all towed HMRG systems.

HMRG has also developed data processing techniques to allow fully processed data sets to be delivered at sea within a few days of final towfish recovery, assuming a full complement of on-board HMRG staff. All raw and final data products are delivered in digital format on a portable disk for further processing or use by the customer as desired. Final products from all HMRG systems are in formats that can easily be imported into commonly used mapping freeware such as the Generic Mapping Tools (GMT) as well as commercially available GIS packages. It is also possible to arrange for pre- or post-cruise training of the customer’s staff in HMRG data processing procedures and/or customer-site use of HMRG-developed software, allowing users to gain a better understanding of HMRG system capabilities and thus plan surveys so as to maximize data quality and better meet their particular needs.

HMRG typically archives customer datasets on internal shore-side storage systems for potential customer-requested reprocessing for as long as is practicable, and is working within the MG&G community to identify permanent archiving options for academic and other public non-proprietary datasets. (A number of processed data sets have been submitted by Principal Investigators to the Marine Geoscience Data System at Lamont Earth Observatory, which provides free public access to data collected throughout the global oceans.) Proprietary datasets are of course handled precisely according to customer wishes with regard to internal HMRG archival (or lack thereof), etc.