In Oldman, like radios, some Speedboats HMG are created at infinite, causing huge lag, huge save file, very long time save/load mission and unplayability in final, after many hours. I found in two places hundreds of Speedboats HMG, without crew and only one with crew, probably the last created. I tried to destroy them but the boats are created at a higher rate.
There are at least two places where this bug apeare, one is at nord of Tuvanaka island at coordinates 3000 - 14000 aprox and in another some bay (I don't remember).