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Old 06 April 2009, 07:07   #11
Country: UK - Scotland
Boat name: Wildheart
Make: Humber/Delta Seasafe
Length: 5m +
Engine: Merc 60 Clamshell
MMSI: 235068449
Join Date: Apr 2007
Posts: 4,614
Only 2nd hole? As I say, I've never seen one of those hulls, but on my Humber the old Yam (identical leg, clamp etc as yours) was 4th out, the Suz on my old SR4 was in the furthest out position! (both boats had quite a rake on the transom)

How heavy is the steering? If it's a "foot on the console" job to haul it round, you could definetly move the pin back.

Another thought - what size is your fuel hose? a 50 won't run too well on the smaller 1/4" stuff used for smaller engines....

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Old 06 April 2009, 07:18   #12
Country: UK - Wales
Town: Here
Boat name: doggypaddle
Make: Avon 5.4 Searider
Length: 5m +
Engine: yamaha 80
Join Date: Jul 2007
Posts: 1,107
Originally Posted by win-or-bin View Post
Cheers, will check the prop this afternoon, just didint think changing the pitch a bit would give me my missing 10knots! What should the max revs for a 50hp 2 stroke be? i thought if it reved to 7k it should go to 7k under load as well?
Thanks for the advice and help
If you give it wide open throttle in neutral it will probably achieve 14,000 rpm briefly before a large chunk of piston flies out the sideDont do it again naughty boy!
You want the RPM to be roughly in the 5000-5500 range, but there is no strict rule , just because an engine can rev safely to 5700rpm does not mean it develops maximum power at thet RPM. Power may peak before that. This allows you to under prop slightly so that when the boat is unloaded your rpm is slightly over the optimum, and as you load the boat if falls back towards max power. This way there is less difference between loaded and unloaded. As suggested try trimming up a hole at a time and see how that affects things. When i look at video of me flat out i am always surprised just how far the engine is trimmed out. you wont be able to trim for max top speed with manual trim as it will probably ventilate in turns and at takeoff , but you can find a good compromise between "bite " and speed. Also worth noting the first time i took my SR out i got 26-27 knots and was disapointed, the sea was not rough only a slight chop, next time out it was like a millpond and i saw 34.9 knots. conditions make a BIG difference to some boats. i am rambling again

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Old 06 April 2009, 09:59   #13
Country: UK - Scotland
Town: West coast, Scotland
Length: 4m +
Join Date: Apr 2009
Posts: 34
Thanks very much for the help, I am learning a lot, previously I have just had wooden fishing boats with tiller steer so these rib things are new to me and when I got it everyone said it would a flying machine, so was a bit disappointed with the speed. I am going to try trimming it as soon as I get the chance to go out again (not easy when you live on the West coast of Scotland i the spring) And will report back, dont think I am going to go with a new prop as a 13" probably isnt going to make much difference and better trying the easy things first!
Thanks again

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