Our heavy derrick has been ()(不用)for a long time.
When the derrick is topped, the guys must be ().
When the derrick is topped, the guy must be ()(放松).
Top the derrick, please.()
When the derrick changes its ()(角度), its lifting capacity changes correspondingly.
Stop()the derrick at once, the gooseneck is bent.
()we swing the port derrick inboard?
A warp end may be fitted for operating the derrick topping wire which adjusts the derrick ().
Please tell stevedores not to ()the derrick.
A warp end may be fitted for operating the derrick topping wire which adjusts the derrick ().