by Guest » December 13, 2023, 2:57 pm
The concept seems kind of simple: utilize the Conflow unloading gear only when discharging commodities like iron ore while retaining high cubic capacity cargo holds for grain by eliminating the need for sloped holds and losing space for conveyor belts running under the holds. In practice, however, the Conflow proved troublesome to operate and surely had a high maintenance cost. I believe there were several instances in which it was reported to be down for repairs. In addition, the weight penalty of carrying this gear, which was likely only used sporadically, limited the amount of cargo the vessel was able to carry due to the amount of draft represented by this mostly useless equipment. Only a few inches of lost draft over several voyages can have a large negative impact on a vessel's seasonal carrying capacity. Another factor is that the efficiency of a self-unloading ship in comparison to a gearless vessel is reduced in direct relation to the distance cargo is carried due to the increased cubic and carrying capacity of the latter. Over longer voyages such as those between the lakes and ports on the St. Lawrence, the ability to carry extra cargo (even marginally) generally offsets the faster unloading rates of a self-unloading vessel. This is why, in simple terms, Algoma and CSL have built some gearless vessels during their fleet renewal projects over the past several years. As the vast majority of the ore cargoes for the Ralph Misener would originate on the St. Lawrence River bound for ports on the lakes, the self-unloading capability played a much smaller role in its successful operation. Every design of a ship has its benefits and tradeoffs to meet a specific goal, and it appears that in this case those at Misener who decided to proceed with such a design felt they had come up with a solution that met their requirements. In the end, however, the Conflow system was ill-suited for operation on the Great Lakes / St. Lawrence Seaway system.
The concept seems kind of simple: utilize the Conflow unloading gear only when discharging commodities like iron ore while retaining high cubic capacity cargo holds for grain by eliminating the need for sloped holds and losing space for conveyor belts running under the holds. In practice, however, the Conflow proved troublesome to operate and surely had a high maintenance cost. I believe there were several instances in which it was reported to be down for repairs. In addition, the weight penalty of carrying this gear, which was likely only used sporadically, limited the amount of cargo the vessel was able to carry due to the amount of draft represented by this mostly useless equipment. Only a few inches of lost draft over several voyages can have a large negative impact on a vessel's seasonal carrying capacity. Another factor is that the efficiency of a self-unloading ship in comparison to a gearless vessel is reduced in direct relation to the distance cargo is carried due to the increased cubic and carrying capacity of the latter. Over longer voyages such as those between the lakes and ports on the St. Lawrence, the ability to carry extra cargo (even marginally) generally offsets the faster unloading rates of a self-unloading vessel. This is why, in simple terms, Algoma and CSL have built some gearless vessels during their fleet renewal projects over the past several years. As the vast majority of the ore cargoes for the Ralph Misener would originate on the St. Lawrence River bound for ports on the lakes, the self-unloading capability played a much smaller role in its successful operation. Every design of a ship has its benefits and tradeoffs to meet a specific goal, and it appears that in this case those at Misener who decided to proceed with such a design felt they had come up with a solution that met their requirements. In the end, however, the Conflow system was ill-suited for operation on the Great Lakes / St. Lawrence Seaway system.