MARINE CONSTRUCTION MYSTERY

Dominion, Volume 1, Issue 87, 6 January 1908, Page 9

MARINE CONSTRUCTION MYSTERY

Thoidiscovery/ihat one-of-tho blades of tho ; : ?biiarl>oard,fcwiii screw of : the battleship Caesar.-i;.-;,' • 'tras*broken off has given nso to sonio into?. ; resting conclusions on the subject of pro- , •pelloß efficiency; Tho-'iriishap"only camb'-to'.'... . 1 ' .'.lifeht .:onritjio, vessel -, being'' docked at Devoii- :: 'f. :r,qcpntly K ,b!Jt)'.fro.m. an ; joa»mination-.of.v ' . ■; ;j;he''bpss,''it Bcejiis that .tlio, mi.shap is.by no; ~ . -. ..mcatiß recent. Tfie mam-engines havo up- ; '.dbubtcdly'-bMii'Vun"since tho, .breakage'hap- 1 . ';'V . ' thd>'faai-;if'.-..' .pljinery gave >•'/ .'dont/recalls; tlici.pxperifincajof tlio battleship ... • Renown, which mado a record passago trom , Bermuda to Dpvnnport at an averago speed -,o{ more than 15 knots. When docked oilier- '' ■ 'l'iVi)]; ; ;it i ..)VttS.,fo.U!id that,.sho Jiad''performed .' : .this .jtea't with..one-,-propeller.,blade knocked .. ■ , awav and another badly damaged, yet there ..was'iio r lbss of-'driving power - or'-'increase in ' ; tlie mean slip of tho. screws. • • • :It,-is fact-jthat.tho,officientVpitch. . area.of a prppcllor-baffles-all.scjen-. ; . ; tific' cal'culation;\iM can only be determined by-practical' piperimbiit. The Dreadnought . . •is : now undergoing ' tests in; this 'direction. '' ' ■ ; ' Several;,of ;,thp '.!Coun':y".cruisers wore simi.larly.iexperimented resulting,, in tho ,o& the Kent and Berwick, man increase , -.of iiearly' otio knot upon tho saino indipat«' ; . ... librso-power.