Depending on the aircraft, a good loadmaster is fairly knowledgeable about mechanical things. I suppose on the big jets at big airports, everything will be provided for you and is fairly straight forward but in the remote areas on big turboprops in the middle of nowhere, you are going to have to estimate weights of unusual items and decide on loading and balance and how to get the damn stuff on board using ingenuity.
Remember that fuel really likes to somehow leak out of old(or new vehicles)or that even though the weight of a particular empty fuel truck may be in your book on weights of vehicles and machinery, it may have a couple of thousand pounds of accumulated sand from over the last 40 years inside.
Be ready to sweat or freeze, and be really cautious. I have seen loads being winched off an aircraft suddenly move sideways fast enough to squish anybody that would have been beside it. It can be dangerous.