When one upbound vessel is overtaking...

Question 1 / 2707066636ee928f7522a1c519d8b

Question 1 of 2707066636ee928f7522a1c519d8b

When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?

Question 1 of 27070

When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?

🔍 Key Concepts

• Hydrodynamic interaction between two tows in close proximity • Effect of upbound current on vessels pushing tows ahead • Which vessel (overtaking vs overtaken) is more affected by disturbed water flow around the towheads

💭 Think About

• Picture two push tows moving the same direction in a river: as one pulls abreast of the other, what does the water between the two towheads want to do—squeeze them together or push them apart? • Think about which tow is in "clean" water and which is in more turbulent, disturbed water as the overtaking maneuver happens. • When a tow has more disturbed flow around its towhead, does that usually make it easier or harder to maintain speed?

✅ Before You Answer

• Be clear on the definitions of overtaking vessel (the one coming from behind) and overtaken vessel (the one ahead). • Visualize the pressure zones and suction effects along the inboard sides of the two towheads as they get close together. • Decide which tow’s engines must work harder due to interaction and current, and which one will be more likely to lose speed.

Question 1 of 27070

When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?

Both towheads will tend to drift together, and the overtaking vessel will be slowed down.

Both towheads will tend to drift apart, and the overtaken vessel will be slowed down.

Both towheads will tend to drift together, and the overtaken vessel will be slowed down.

Both towheads will tend to drift apart, and the overtaking vessel will be slowed down.

Question 1 / 2707066636ee928f7522a1c519d8b

Question 1 of 2707066636ee928f7522a1c519d8b

When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?

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Question 1 of 27070

When one upbound vessel is overtaking another vessel and both are pushing a tow ahead, what reaction may you expect?