Download BinEdit and follow the included instructions to set it up (
make sure you set the file directories in the preferences!!!).
To raise the boat,
File menu -> Open and select the boat model,
Model menu -> Translate, enter the required value in the 
Y box and click OK,
finally 
File menu -> Save or 
File menu -> Save As... to save the model ("Save" overwrites the original file and may be used if it is your own model that hasn't been used anywhere else; if you are modifying someone else's model and/or it has been used elsewhere, use "Save As" and give the model a unique name).
BE tutorials/help documentation are 
here and 
here.