ABSTRACT
AREA UND. CUR. OF STAT.STAB.LEVER UP TO 30 D = 0.227 M RAD AREA UND. CUR. OF STAT.STAB.LEVER UP TO 40 D = 0.322 M RAD AREA UND.CUR.OF STAT.STAB.LEVER BET.30&40 D = 0.095 M RAD RIGHTING LEVER AT 30 DEG INCLINATION = 0.554 M ANGLE OF INCLINATION OF MAXIMUM LEVER = 0.4 5 RAD MAXIMUM RIGHTING LEVER = 0.560 M AREA BET. CUR.OF HEEL & RIGH.LEVRS. UP TO 40D= 0.298 M RAD RATIO OF HEIGHT OF C.G. TO DEPTH = 0.700 NATURAL PERIOD OF ROLLING = 2.904 SEC NATURAL PERIOD OF PITCHING * 3.494 SEC NATURAL PERIOD OF HEAVING = 3.756 SEC PERIOD OF ENCOUNTER (ROLLING) = 2.400 SEC PERIOD OF ENCOUNTER (PITCHING) - 0.921 SEC PERIOD OF ENCOUNTER (HEAVING) - 0.921 SEC FROUDE NUMBER - 0.433 CAVITATION NUMBER = 0.345 RATIO OF THRUST/UNIT AREA TO STAG.PRESSURE = 0.146 SURFACE AREA OF APPENDAGES - 47.03 SQ.M WETTED SURFACE AREA OF HULL =209.80 SQ.M WAVE RESISTANCE * 64.11 KNEW TOTAL RESISTANCE - 89.60 KNEW WAKE FRACTION - 0.036 THRUST DEDUCTION FACTOR - 0.048 RELATIVE ROTATIVE EFFICIENCY - 1.003 EFFECTIVE HORSE POWER = 200.96 KW TOTAL BRAKE HORSE POWER INSTALLED - 1225.00 KW DELIVERY HORSE POWER = 1151.50 KW BOLLARD PULL WITHOUT OVER LOADING THE ENG. - 20.05TONNES REVOLUTION PER MINUTE AT BOLLARD PULL COND. - 239.794 REQUIRED DHP FOR SERVICE CONDITION - 566.18 KW LIMITING VALUE OF TOWC AT FREE RUNNING COND. - 0.146 CALCULATED VALUE OF TOWC AT FREE RUNNING COND.« 0.024 LIMITING VALUE OF TOWC AT BOLLARD PULL COND. « 0.185 CALCULATED VALUE OF TOWC AT BOLLARD PULL COND.- 0.183
JOB COMPLETED ON: 24-OCT-91 AT: 10:01:41 HOURS
THE DESIGN AND CONSTRUCTION OF A CLASS OF VOITH TRACTOR TUGS
PHILIP AARON B.Sc. C.ENG. F.R.I.N.A. Divisional Managing Director
McTAY MARINE
ABSTRACT
In November, 1989 Humber Tugs Limited, part of the Howard Smith Group, placed an order with the McTay Marine Division of Mowlem Regional Construction Limited (now John Mowlem Construction pic) for five Voith Water Tractors. The paper describes the conceptual design requirements of the Owners and examines the design procedures and construction details used by the Builders to satisfy the Owners requirements. The trials results of the Class are compared with the initial requirements. The final section comments on the operating experience of the Class since they went into service.
