I am not familiar with that particular term, but 'Calahan' states that до- as a prefix with verbs is ad-. So, it depends on the context. But it does make sense that, for example, a vessel outfitted to fish with a trawl could add equipment to allow it to fish longline.

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Note added at 2002-03-26 05:09:01 (GMT)
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Researching further, I found that \'Oxford Russian-English Dictionary\' shows that \'до-\' used as a prefix to verbs \'...expresses completion of action...\'. So, дооборудовать could also mean to complete (finish) outfitting the vessel for long line fishing.

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The company plans to complete fitting out the vessel...(or "outfitting the vessel")
First reference: "Outfitting/fitting out is the final step in the process of providing initial material support to operational units. The end products of the fitting out process are all items of material as specified in the authorized allowance lists stowed in their proper locations on board the ship, and the standard documentation for locating these items on the ship. MIL-STD 1339C (SH) defines Fitting Out and Outfitting as follows: "Fitting out is the operation of placing on board ship all of the material specified in its allowance lists. For the purposes of this standard, the functions normally associated with the term outfitting; for example, ordering, funding, expediting, follow-up, receipt and inspection, are included in the definition of fitting out."
Second reference: "Ship or erection units are outfitted with propulsion equipment and support equipment, such as plumbing, electrical installations, etc. (Also includes painting operations after assembly, but these hazards are covered under "painting.")"

The Company plans to equip a fishing-boat in addition for long-line fishery