Looking for description of ferrys unloading

[NPSJOHN]

Hi,

I am trying to find a description of how ferrys can stabilize their docking or unloading while pushing against the dock (or whatever tstructure they are trying to dock against).

I know it's common practise for captains of ferrys and other vessels frequently loading and unloading to simply push against the dock instead of tying off, but I really need a description of it. Does anyone know of a manual, book, or webpage where this practise is described it would be of great help!

Thank you!
/John

 

[MikeHalloran]

I've seen water taxis do it for passenger discharge.

I've never seen a vehicle ferry do it, except to put some preload in the hawsers before cinching them up and dropping the ramp.

I'm not saying it's never done, but given the separating force that is potentially generated by a vehicle on a slanted ramp, I'd have to classify the practice as dangerous, and I'd guess it must be illegal somewhere.

It's a bad idea from another standpoint; churning the (shallow) water near a ferry dock could put all sorts of stuff into the engine's cooling system, which generally doesn't do it any good.



Mike Halloran
Pembroke Pines, FL, USA

 

[L4189]

Here in Washington State we have a pretty good tidal range and the ferries move into a specially designed slip for proper alignment against tidal currants. The ramp is aligned in 2 stages. controllable. First there a long ramp from shore to the staging float then a short ramp raised and lower by a electric winch operated by the deck hands. The deck hands also tie up to the float but there is a famous accident about 20 years ago where in the process of load the controllable pitch propeller reversed and dumped a car in the water. The occupants were promptly rescued.. At low tide it can be a steep climb up the ramp to shore.

 

[pauljohn]

There is a roll-on/roll-off ferry that runs in the Upper Peninsula of Michigan that regularly does this, in fact I have never seen it tie up unless they are on a break!

Ferry capacity is about 30 cars or maybe a couple of semi trucks and a few cars. The ferry dock is L-shaped and has an adjustable ramp on the shore side. When the ferry gets to the dock the bow is pushed against the loading dock and also against tires that are on the pier that runs alonside it so it is contacting the front and side of the ferry. They then lower the front ramp to the appropriate level and also adjust the shore side ramp, the ramps are also adjusted occasionally if the load shift is large in the middle of loading/offloading. This happens a lot when there are semis on board. Engine noise is minimal so I assume the ferry is in gear with props barely turning.

If you need more info I know one of the captains that drives it. In fact I will be on it again in a few weeks so could ask or find out for you.