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 TB 55-1900-232-10
FIGURE 2-15. Towing Alongside.
For towing alongside, the tug generally secures to one side of the tow with her own stern well aft of the stern of the tow to
increase the control effectiveness of her propellers and rudder.
CAUTION
When towing alongside, keep all lines taut until ready for streaming the tow. This will prevent the tow from
pounding alongside the tug and ensure effective control of the tow.
2-5.2 SINGLE TUG, MULTIPLE UNIT TOW. Single tug, multiple unit tows consist of one tug and several tows; the
connection and makeup of the tows can be varied. In current U.S. Navy practice four versions are used. The Christmas
Tree rig and the Honolulu rig are used for open-ocean towing. The Tandem rig, when the tows are close-coupled, usually
is used only in congested waters where good control is required The fourth type, the Nested rig, is restricted to protected
waters.
a. Christmas Tree Rig. The Christmas Tree rig requires a review of water depths and bottom conditions prior to its use.
The catenary of the towline from tug to first tow and subsequent connecting wires must be deep enough to ensure that
the undesired passes safely below the bow of the leading tow(s) It is important to have adequate water depth to
prevent grounding the towline. With the assistance of harbor tugs, it is feasible to break out one of the tows without
disrupting the remainder.
Harbor tug assistance usually is required to break up the Christmas Tree rig before entering port. Although a strong
rig, it is difficult to make up and disconnect and does not facilitate getting all elements in step Figure 3-16 illustrates
this rig.
2-23
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