Manufacturer's suggested prop size?

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FredBMOC

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Ladies and gents,

My purchase of the Sunseeker Superhawk 48 is progressing nicely so I have been reading as much as I can about the boat, engines, etc. One of the articles I have been reading is about overpropellering a boat and the detrimental effects on engine service life so I wanted to make sure that the props now fitted are the correct ones for the boat; how do I go about finding out what Props Sunseeker originally fitted on the SH48 with KAD300 Volvos engines and outdrives?
 
I guess that someone at Sunseeker should be able to answer your question, but why are you in doubt, to start with?
A proper sea trial should reveal if the boat reaches its max rated RPM/speed, and if she does, you can safely assume that the props are fine.
And you don't want to purchase anything afloat without a proper sea trial...
 
As stated above by MapisM,when at WOT engine should get very close to recommended max RPM.Which should in turn get you the approx top speed of boat.You need to bear in mind age of engines and all that junk that boats seem to mysteriously gather up over time and state of weed and muck on bottom,which curiously does NOT make the boat go faster .
Ebay is full of props with odd pitches because somebody thought they could improve on the builders 50 odd years of bolting props on boats.
Get it wrong and you will not only waste money on props but you could damage engines.
It may be worth remembering that all new boats are tested for top speed with a pint of fuel in both water and fuel tanks and special plastic anchor and chain on board,an anorexic jockey at the helm and any plastic sheeting on the upholstery removed to save weight.:)
 
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Mapis, oldgit,

thanks for the replies... the surveys and seatrials were done and all seems well with the boat, I am just a little anxious while I wait for the closing and perhaps looking too hard for issues to fix ;-) . There were a couple of issues found during the survey that are being repaired now and next week we will do another seatrial to see how everything looks, hopefully we will have good weather to run the engines to their max; one of the problems we had during both seatrials we have done thus far is that the seas were big and we couldn't reach max speed and RPM and next week we may be in for more of the same. I might have to take the boat down to Miami's Key Biscayne to try to get max speed and RPM in inland waters instead.
 
FredBMOC said:
one of the problems we had during both seatrials we have done thus far is that the seas were big and we couldn't reach max speed and RPM and next week we may be in for more of the same.
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All the best for your next seatrial.
Fwiw, I would do whatever it takes, rather than buying a boat like that without having had a chance to see how she behaves while accelerating from idle to WOT (cleaning props and hull first, if necessary).
You and/or your mechanic should check at least the following:
- constant and "parallel" acceleration of both engines;
- rated max RPM on all mills and rated speed, with no or little smoke;
- correct temperature anywhere (checked also inside the e/r, with a temp gun), oil and water pressure;
- no unusual vibrations;
- straight course.

Btw, back to your original question: if the boat behaves as she should at WOT, that's an acid test also for props. No planing boat on earth would perform properly at WOT with significantly wrong props! :)
 
Will the Sunseeker be based in the Med?
Even then new prop changes are to be made, and the builders knowledge of this will depend how much they sell of them in the area. Usually the med boat will need props with a pitch smaller.

As MapisM stated correct max engine revving will be your best bet.
 
EME said:
Not sure that follows, in my experience water is warmer in Southern Florida (where the OP is based) ... so interested in why that is recommended too.
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in the oceans density of salt water is approx 1025kg/m3
in the med , density is approx 1030kg/m3

naaa I can't believe this makes a difference
 
BartW said:
in the oceans density of salt water is approx 1025kg/m3
in the med , density is approx 1030kg/m3

naaa I can't believe this makes a difference
Click to expand...

May be density plus heat! We have 20 plus seas here in central med from May till October. Sometimes even touching 28 deg celcius as this summer.
What i know is that many Farilines, Princess and Sunseeker which are shipped here, usually have ther props changes. Especially if its a very new model i.e. never shipped to the med.
 
You're all missing the point, folks.
Down here in the Med, boats are overloaded with all sort of toys: PWCs, diving gear, cases of champagne, you name it.
Not to mention the parade of babes sunbathing on stern cushions. Didn't you see the brochures?
Shorter props are a low price to pay, for this lifestyle... :D
 
MapisM said:
toys: PWCs
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wtf is that?
it cannot be pricewaterhousecoopers, nor pc weekly...
How about professional women in construction :confused:

plz explain!

on a serious note, yes temps + gennies + AC + large water tanks + lots of ppl onboard would make sense on a anyway stressed system as it stands.
 
virtuvas said:
that's a cryptic and rather convoluted way to say tenders and jetskiis though, innit?
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Yep, but I actually thought that "personal water craft" was an even more common definition than jetski. Maybe that's more a US of A thing... or it might be just my impression! :)
 
It is always fun to see where a thread goes when you take a few days off the forum ;-)

I will load all of the dive gear and junk we will be carrying on the boat and do a proper trial to see if the props need changing; Wednesday we should do the final sea trial before closing.
 
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