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Re: Frontenac boom mount

From: Eric
Location: Duluth
email:
Remote Name: 71.10.72.32
Date: 12.18.08
Time: 02:30:23 AM

Comments

What you're seeing isn't just the mounting structure for the unloading boom, it's the casing which contains all the above-deck parts of the vessel's unloading system. On nearly every self-unloading bulker that casing houses the upper half of a system of looped conveyor belts (most self unloading systems built or installed since the mid-70s), incline belts (the unloading system on a lot of the 70s-vintage U.S. river-class and Bayship seaway-size boats), or bucket elevators (most unloading systems dating to before the early 70s). Whichever system is present, the purpose is to lift the cargo from the below-hold conveyor belts up to the level of the unloading boom, as well as some supporting machinery/equipment. In loop belt self-unloaders the lifting mechanism consists of one set of looped conveyor belts (two belts which pinch the cargo in between and carry it upward in a big vertical half-circle) mounted fore-aft along the vessel's centerline. That means the above-deck loop belt casing/tower doesn't span much of the vessel's width; instead its biggest dimensions run fore/aft. If I'm not mistaken the Canadian self-unloaders with that massive casing (Frontenac, Halifax, Algomarine, Algosteel) also have loop belt systems, but instead of one centerline fore-aft set of belts, they have two loop belt setups mounted transversely (side-to-side). This is comparable to taking two versions of the unloading system on, say, the Beeghly and pivoting them each 90 degrees inboard, so that they point in toward each other and discharge toward the center-mounted boom. This takes up less fore-aft space on the boat and maybe leaves more room in the cargo holds, but does take up almost the entire width of the ship and makes for a pretty top-heavy/ungainly-looking structure.

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