Question 57 TV02 - Towing Vessels - Great Lakes and Inland

The Correct Answer is D **Explanation for Option D ("All of the above"):** Excessive catenary refers to having too much cable or chain (the catenary) deployed relative to the water depth or the required horizontal tension. In shallow water, having too much scope creates a deep, U-shaped curve that rests on or near the seabed. This condition leads to all the hazards listed in options A, B, and C, making D the comprehensive and correct choice. **Detailed Breakdown of the Effects (Why A, B, and C are true):** * **A) Dragging the towing hawser along the bottom and chafing it:** When the catenary is too deep, the cable or chain necessarily contacts the seabed over a significant distance. This friction causes rapid wear, abrasion, and potential chafing damage to the towing hawser or wire. * **B) Snagging sunken or submerged objects:** A long loop of cable dragging along the seabed acts like a giant rake. It is highly susceptible to snagging rocks, pipelines, anchor chains, wrecks, or other submerged debris, potentially damaging the hawser or bringing the tow to an abrupt, dangerous stop. * **C) Slowing, stopping or endangering the towing operation by placing the tug in irons:** Placing the tug "in irons" (or being "girted") occurs when the tow line runs directly perpendicular to the tug's centerline, potentially pulling the tug broadside to the direction of travel or the waves. Excessive catenary, especially when combined with sudden stops or snags, can create massive, unexpected resistance and side-loading forces that make the tug unmanageable, endangering the entire operation. **Explanation of Why Other Options Are Individually True (But Not the Best Answer):** Since options A, B, and C are all valid and significant hazards caused by excessive catenary in shallow water, none of them individually captures the complete risk profile. Therefore, D, which encompasses all three proven effects, is the most accurate response.