Interesting about the need for a different number of blades and smaller diameter - I will keep an eye out for that - thanks!
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Thrust differences between petrol outboard and inboard diesel of same horsepower
- Thread starter RSD
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OK that active corrosion protection might be a good thing to have - especially on an aluminium boat! Pulling the boat out once a year is a bit more practical - its about 55nm t0 wear the boat can be pulled out so once a year instead of once a month is a bit more practical.
....not so much about finding it but to avoid equipment needing dismantling "in the wet" to fix a simple impeller change.
Another concern: you consider dynamic positioning in a vessel with open propellers and divers in the water.....really!??? What's your insurance company?
Another concern: you consider dynamic positioning in a vessel with open propellers and divers in the water.....really!??? What's your insurance company?
Yes - has been done many times - there is a technique that we have successfully used before.
In your experience, what sort of hours would a commercial operator get before needing to replace a D6 480hp engine and/or the stern drive? Say only doing 20% of the hours at around 3000 rpm, the other 80% doing various revs in dynamic positioning?
gonzo
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At moderate loads the usual hours to rebuild the engine is about 5000. The 480HP is the highest rating the engine is manufactured to, so don't expect more than that. However, you don't need to replace the engine. Rebuilding is a lot cheaper. The sterndrives often last as long as two engines if they are maintained properly.
OK many thanks - that helps heaps!
Interestingly this video was released yesterday and popped up in my feed - it is 11.6 x 4 metres - so in some ways close to my desired 11.9 x 5.5 metres - runs a pair of 340hp D6's through DPI drives - performance figures are listed in the "more info" section below the video.
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What I might try and do seeing as I don't have any GA drawings for it is try to create a plan drawing from carefully watching the video to try to see if there is enough space on the rear deck for our desired number of divers, and also to try to model the interior of the cabin to see if we need everything that they have in there to see if the cabin length can be made a bit shorter to increase deck space.
They say that it is 38' - how/from where to where is that measured in the U.S.? That would probably be obvious to most people - but coming from Australia where AMSA have unusual and complicated formulas for determining the length of a vessel its a question that I need to ask - because amongst other things AMSA have three different ways of measuring from/to and then formulas that are approved to determine the length of a vessel to determine which category it fits into - each formula usually gives a different answer to the others, and so designers can choose the formula/answer to potentially put the vessel just into a higher category which means that it can go further offshore, or into the lower category which means that the captain requires a lower level of licence.
Would the small duckboards on the stern be included in the 38' ?
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When various regulations refer to, for example, vessels smaller or larger than 24 m, they are referring to the hull length, which includes everything that contributes to the hull's buoyancy reserve. There are other lengths, such as the length between perpendiculars, which is no longer used, the waterline length, or the rules length, which each regulation specifies how to measure.
So effectively tip of the bow to transom and rounded up to the next foot? I can work with that.
This is one example of the stuff we have to navigate through in Australia -
The measured length of a vessel is the greater of:
(a) the length on deck, in metres (LD); and
(b) 0.96 times the length overall, in metres (LOA).
...and things get far more complicated than that... to the point where there is a 35 page guidance note just about how the length is to be measured and determined...
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