Clif, You remark is very interesting, but as far as I know this is a semi-sub crane and they do some ballasting to position and compensate the weight to be lifted. If one of our fellows ME has a more comprehensive explanation this can be of interest. Pierre pierre.courbouleix@xxxxxxxxxx MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.