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on the face if it it is concerning my 2013? 16hp twin came standard with the ZF10 M rated from 33 - 51hp so the gearbox was 2x over-spec for the engine's power rating your, almost double, 29hp engine has a gearbox rated half mine as the HBW50 became the ZF 5 M, which was replaced by the ZF 6 M which is only rated at 23 - 27hp seemingly under-spec... http://simplicity-marine.com/Hurth-ZF.htm so you'd have to think why they went double-spec on later engines? perhaps because the earlier trans were not up to scratch? so maybe - keep revs well below r

http://www.universal-diesel.no/files/Gamle%20motorer%20brosjyrer/M30%20PERAMA.pdf 6th hit on this search https://www.google.co.nz/search?q=perkins+m30+power+curve&safe=off&biw=1242&bih=580&source=lnms&sa=X&ved=0ahUKEwj0toznvPrRAhXCrJQKHWOZCn4Q_AUIBygA&dpr=1.1#safe=off&q=perkins+perama+m30+29+hp+marine+diesel+engine+specs

don't really want to 2nd guess professionals but 30hp seems enough to push along an h28 at hull speed without needing to be red lined and if the engines not needing to output its max hp the gearbox should be ok if you were concerned you could look at adding an oil cooler

what's the gearbox?

gearbox hp rating is similarly complex my hurth ZF10 M manual listed 4 quite different hp rating depending on duty cycle and gearbox ratios ranging from C - duty - continuous at fixed rpm, (commercial trawler etc) max input 20-31hp P - duty - light (private planing hull) 30-51hp as it was my mitsubishi twin based engine was only 16hp so it didn't matter but if someone had only looked at the headline specs of "up to 51hp" and mated the gearbox to a 40hp engine and used it continuously at a fixed rpm they would eventually come to grief and the warranty would proba

if you send me the pic via email can try to upload to a crew gallery then link here

my little 25' keeler had a 16hp engine with 2.5:1 reduction gearbox weighed more than 25' cav/salthouse/reactors with more wetted area, (almost full keel) and only 20' waterline subject to pitching as it was a narrow double-ender it had a 3 bladed,15 x 10 prop which would get it pretty easily up to 5 knots at medium revs, no rev counter taking the revs higher in flat water didn't make it much faster, it just screamed and towed a big hole + wave behind the boat https://youtu.be/quImf233by8?t=29

gearbox ratio? 2nd page of the spreadsheet 29 - Engine Horsepower 3600 - Engine R.P.M. (max) 42 - Engine Torque ft/lb 28 - SHP - Shaft Horsepower at gearbox output. 3 - Enter number of bearings between gearbox output and propeller. 2.00 - Enter Gearbox reduction ratio. Eg. 1.5 4.50% - Percentage power loss due to shaft bearings. 28 - Shaft Horsepower at propeller. 1800 - Propeller RPM 82 - Propeller Torque ft/lb

^ blade ratio area presumably there is a standard blade area ratio for normal speed, displacement drive props operating in water as even the props on the titanic look to have the same basic ratio as the tiny plastic props on AA battery boat toys sure special purpose props running at the surface or inside ducting start to look different but the h28 probably fits quite comfortably between the above extremes and once the viscosity of the medium changes dramatically, ie air, so does the basic prop shape lots here https://www.vicprop.com/propeller101.htm

so banging the numbers you've given for hp (29), rpm (3600) + desired top speed (6) into the prop calc spreadsheet above plus the displacement of a loaded compass h28 (12000lb) and water line length (22.8') spits out a recommended 3 bladed prop of 14 x 8 with an alternative of a 13 x 10 (for if there are space issues etc with a 14' diameter prop) interesting the calcs on the prop pitch page 6 - Speed in knots required from Power Reqd page 1800 - Max prop shaft rpm from Torque & SHP page 1440 - 80% of max prop shaft rpm 608 - desired speed expresse

online prop calculators can be useful for checking if props are matched well to boat + engine if you've got all the numbers https://www.vicprop.com/displacement_size.php a more techie spreadsheet calculator downloadable here http://www.marineengine.com/boat-forum/showthread.php?291976-Internet-prop-calculator

wheels of justice grinding slowly and finely Police have been granted a warrant to arrest Simone Anne Wright – the partner of a man already in custody on 60 charges – on a charge of stealing a $145,000 yacht at Paihia in the Bay of Islands last year. He faced 60 charges, including one of stealing the yacht, thefts, frauds, and causing people to act on forged documents. Police have also charged him with indecent assaults on a 15-year-old girl in Auckland in 2008 and supplying her with the class B drug MDMA, or ecstasy. The charges allege offending in Paihia, North Shore, Au

sharks eat baby dolphins orca eat dolphins and sharks in nz sharks will jump out of the water and on to rocky reefs to get away http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11510130 not hard to imagine a big 5m? great white going for a baby orca and also easy to imagine a pack be mustered for a bit of house cleaning mid-ocean orca will spend days teaming up to tearing chunks out of blue whales that are steaming along non-stop streaming blood sea wolves another name

Prior to the absence of white sharks, several killer whales cornered and killed a white shark close to the islands, off the coast near Adelaide, he explained. "Killer whales are the ultimate top level predator in the ocean's surface waters. White sharks may have been responding to this 'life-threatening' cue and fleeing the area." Local fishermen have been telling tales of a great white shark larger than a boat - some say up to 9.4m - just off Stewart Island. Last year terrifying video footage of a mega shark apparently attacking a tiny boat near Picton made waves online. only

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