It really depends on what era you are modelling. Take a look at post 274 onwards for a detail of my anchor on the following topic.
http://www.modelboatmayhem.co.uk/forum/index.php/topic,46369.250.htmlFor the most part from around 1800 up to the 1920's sailing trawlers had kedge anchors, and as they were stored inboard usually strapped to the port rail, they had to be manhandled overboard. So for the most part they were not to large or heavy that two men couldn't physically lift it over the rail.
A few posts later on in my build you will see the scale of it compared to a figure, this model was built to 1/48th scale, so I made the thing, but any kedge anchor that is commercially available and fits somewhere close to your model would be ok. Remember back at the turn of the century any ironwork was made by the blacksmith of the shipyard or in the near locale, so differences in size shape would creep in.
If its a sailing craft after this date then you will have to do some deep research to find out!