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R/V Knorr Winches & Wire

Overview

Knorr is outfitted with three permanently installed oceanographic winches used to deploy scientific instrumentation. The winches hold UNOLS ‘standard’ 1/4” and .322” electro-mechanical hydrographic wire and 9/16” trawl wire. A WHOI-owned portable traction winch system, designed to handle UNOLS ‘standard’ .68” fiber optical cable can be installed on the vessel.

The two hydrographic winches share a common overboarding point, the hydro boom, which is described below. The trawl winch wire is overboarded through the starboard aft ship’s crane.

Winch drums holding .322” E-M cable are equipped with slip ring assemblies for transmission of signals from the rotating drums.

Hydrographic Winches

Located on the starboard side midships on top of the forward hanger and port side 02 Deck. Winch particulars (same for both winches) are:

Winch particulars Winch 1 Winch 2
Model: Markey DESH-5 Markey DESH-5
Power: Electric, AC-SCR/DC, 75 HP Electric, AC-SCR/DC, 75 HP
Rated Line Pull: 10,300 lbs. bare drum
5,926 lbs. at 102 m/min, mid-scope
4,547 lbs. at 133 m/min, full drum
10,300 lbs. bare drum
5,926 lbs. at 102 m/min, mid-scope
4,547 lbs. at 133 m/min, full drum
Average Working Speed: 60 m/min 60 m/min
Wire Capacity: 10,000 m of .322" E-M cable
9,200 m of 1/4" wire rope
10,000 m of .322" E-M cable
9,200 m of 1/4" wire rope

These winches have interchangeable drums that allow changing of cable type without a spooling operation. Drum changes take approximately four hours using the ship’s crane but must be done in port. The cables lead from the winches through fixed fairleading sheaves to the overboarding block mounted on the extendable hydro boom. All sheaves in the train are a minimum of 12” tread diameter. Sensors for the wire monitoring system are mounted on one of the fixed sheaves.

The winches are controlled from an operator’s shack mounted adjacent to the starboard winch above the mid-ships hangar. The operator has a clear view of the winches, the sheave train, over the side and the deck work/landing area. The operator has intercom communications with the bridge and laboratories. Winch parameters (line count, line speed and tension) are displayed at the winch control, in the Main Lab and on the bridge.

Traction Winch Facility

In 1991 WHOI purchased a portable traction winch system and a .68” optic-electro-mechanical cable with private funds to support the operational requirements of the recently established Deep Submergence Operations Group (DSOG). The traction winch and a UNOLS ‘standard’ .68” fiber optical cable are available to other scientific programs scheduled aboard Woods Hole operated vessels when not committed to DSOG.

The hydraulic traction winch system, built by Dynacon Inc. of Bryan, Texas, is designed specifically for deep-ocean towing of large instrument packages requiring long lengths of .68" fiber optical cables for prolonged periods of time. The system is portable, and is capable of being shipped by motor freight. The hydraulic pumps are driven by electrical motors powered from the ship’s electrical supply. A diesel prime mover is available for use where ship’s power is not adequate.

The winch system is composed of four major components: the traction head assembly, the storage reel, the level-wind unit and the electro-hydraulic power unit. Included in the system are winch control units, winch readouts, overboarding sheaves, cable terminations and a slip ring assembly. Particulars of the winch and coaxial cable are:

Winch and Coaxial Cable particulars            

Model: Dynacon Inc. Hydraulic Traction Winch
Power: Electric, AC-SCR/DC, 200 hp
Rated Line Pull: 50,000 lbs. static
                        0 to 30 meters/min at 42,000 lbs. continuous
                        0 to 122 meters/min at 10,000 lbs. continuous
Average Working Speed: 60 meters/min at 20,000 lbs. continuous
Wire Capacity: 11,000 meters of .68" armored cable
Weight (winch): 42,500 lbs.
Weight (9,150 m cable):
.68" fiber optic cable - RBS: 46,000 lbs.
.68" fiber optic cable - SWL: 20,000 lbs.
.68" fiber optic cable - min radius: 48 inches

The winch system is operated as a cost center administered by the WHOI Marine Department. There is a uniform daily charge to all users of the traction winch facility to support the maintenance and spare part inventory of the winch and the staging of cruises. The charges are assessed for all at-sea days regardless of winch use. In-port days are not charged. A winch technician is required aboard for all cruises. Labor charges for this technician are not included in the day rate.

Hydro Boom

The Hydro Boom serves as a common overboarding support structure for the hydro and CTD cables. The overboarding point is located amidship on the starboard side, the area of least ship motion in a seaway. The unit is a hydraulically powered extendable boom mounted on the 02 Deck. Two head blocks, for the hydro and CTD winches, are hung from the end of the boom. When the boom is retracted, the wire plumbs 10 feet aft of the forward hanger centered in the access door. A bulwark gate can be opened to allow passage of instruments. Particulars of the boom arrangement are:

Vertical clearance above main deck: 19 feet
Clearance from hull, max. extension: 15 feet
Clearance from rail, fully retracted: 5 feet
Safe working load: 12,000 lbs.

The hydro booms do not raise or rotate. Controls are located at the hydrowinch operator's control station.

Oceanographic Cables

Three standard categories of oceanographic cables (trawl, electro-mechanical/CTD and hydrographic) are available on board WHOI vessels.

The significant characteristics of each wire are given in the following table.
                       

  Trawl Hydro E-M/CTD
Size 9/16" 1/4" .322"
Length 6,506 m 9,152 m 9,764 m
Construction 3 x 19 galv. 3 x 19 galv. 2 armor galv.
Manufacturer Macwhyte Macwhyte Rochester
Manuf. ID 9/16" AA 1/4" AA 01592
R.B.S. 32,500 lbs. 6,750 lbs. 11,600 lbs.
Yield 24,375 lbs. 5,063 lbs. 5,500 lbs.
2% Yield 28,600 lbs. 5,900 lbs. ---
S.W.L. 14,300 lbs. 2,950 lbs. 4,500 lbs.
Wet Wt. 1,370 lbs./km 284 lbs./km 462 lbs./km
Dry Wt. 1,614 lbs./km 327 lbs./km 571 lbs./km
Min. Sheave Dia. 21" 12" 12"
DC Resistance @ 20 deg --- --- 3 cond., 9.4 ohm/1,000'

Spares exist for each type of oceanographic cable. In general, where space and availability permit, spares are carried aboard. On extended multi-leg cruises backup cables are always placed aboard. Spare hydrographic and E-M/CTD cables are stowed in the hold.

All oceanographic cables aboard WHOI vessels are lubricated during manufacture with Grignard Chemical Co. Pre-Lube #6 or #19. Cables are periodically rinsed and lubricated with the same product during service.

It is imperative that oceanographic cables be used in a responsible manner which does not compromise their availability to subsequent investigators. Cables are expensive and at times in short supply. Reasonable care must be taken to maintain their integrity and extend their useful life. Questions related to the use of cables should be directed to the Marine Operations Coordinator during cruise planning.

Notes, cautions, and restrictions to the use of cables:
1. Cables are not to be loaded in excess of their safe working load. Caution must be exercised in lowering instruments which are heavy, entrap large volumes of water, or produce excessive hydrodynamic drag forces. This is particularly true when operating in moderate sea states or water depths greater than 4,000 meters.

2. Cables will not be permitted to pass over sheaves which are not properly sized (groove size and tread diameter) for that cable.

3. In general, devices are not to be clamped onto any conducting cable. This is to prevent damage to conductors and their insulation. The exception is that devices may be clamped within 100 meters of the termination.

4. Certain operations, such as dragging for moorings, deliberately subject cables to severe abuses such as kinking and abrasion. Whenever possible, the main cables will be protected from abuse by splicing or attaching sacrificial wires of comparable strength to the end.

Trawl Winch

The trawl winch is located below decks on the starboard side of the after science hold. Winch particulars are:

     
Winch particulars
Model: Northern Line 3155-ETRW
Power: Electric, AC-SCR/DC, 150 HP
Rated Line Pull: 24,000 lbs. bare drum
5,200 lbs. full drum
Average Working Speed: 50-60 m/min
Wire Capacity: 9,200 m of 9/16" 3x19 wire rope

This is a single drum winch. The wire is led from the winch through a series of fairlead sheaves mounted below decks to the ship’s trawl crane which serves as the overboarding point for the wire. There are a total of four 21” diameter sheaves in the sheave train. Sensors for the wire monitoring system are mounted on one of the fixed sheaves. Construction of the sheave train prevents the passage of shackles and other fittings. Special rigging is required to handle long net bridles, pendants and terminations.

The primary winch control is located in an operator's booth mounted atop the after hanger. The operator has a clear view of the entire main deck work area and instrument landing spots at the stern and the starboard side. The operator has intercom communications with the bridge and laboratories. Winch parameters (line count, line speed and tension) are displayed at the control stand, in the labs and on the bridge. An auxiliary control stand is located at the winch below decks. Provisions are made (with advance notice) for the use of a remote control station which can be placed in the main laboratory. A closed-circuit video system allows monitoring of the below-deck winch and sheaves as well as main deck activities.

The overboarding sheave is mounted on the end of the main boom of the trawl crane. The crane can be positioned either over the stern for towing operations or over the starboard side for coring and instrument recovery. The crane boom is raised and rotated to launch/recover instruments. When lowering instruments, the crane boom is placed in a crutch for added strength and to relieve the stress on the hydraulic system.

Last updated: January 8, 2007