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G'day nq,
I've still got the foil on for now, the engine seems to rev up when turning even slightly but the speed appears to increase slightly as well {1-2 k's} is this caused by less drag in a turn ??? the old prop rev'd up but the boat slowed down as though losing traction. You'll have to forgive my ignorance about these things Ive only ever had a 3 mtr tinny before this boat and none of this mattered. All / any advice is appreciated.
woody
Woody I dunno, is your foil out of the water when on the plane? Strictly it should be. Possibly the turn causes a dip in the water around the foil and exposes it or half of it? The decrease in drag might do it.
The cav plate has served it's purpose by the time you are on the plane, the hull should be doing all the lifting at this stage so the foil should be high and dry, at least the top with the bottom skimming at worst, your motor may be too low if the foil stays a foil at speed.
Only you know how you like your boat so sucking an experiment for a little while until you get a feel for how much better or worse it is can be worth it.
All that matters is that your happy with any outcome, not what is supposed to be right or wrong.
I hate foils but there has to be a reason most Hornet owners fit them, when you have the time and inclination try a few runs without it.
The placement and amount of cup and a manufacturer put in is very subjective so I have not the first idea what that prop would or should do over your old one ???.
The second best thing to being out in a boat is talking about them, I wouldn't call you ignorant at all, when it works for you, you will know. cheers nq
nq,
I've never really taken any notice where the foil is at speed but I will on the weekend. I do remember someone posting their engine's height details { hole number wise} on a post somewhere and mine is lower than theirs was but thanks for the help I've got some playing around to do.
woody
Hi Nq
well the legs back on, test today
prop 13 3/4 X 15
revs 5800
gps speed 54km
holeshot - make sure ya hang on
I think I need to get a 13X 18P
or
a 13 3/4 X 16P which would split the 2 props I have
At the moment the boat still has the 13 3/4 a 15P prop on as it seems like it holds its head better and is more responsive to trim, not so much talking about bow lift but when trimmed correctly there is a good increase in revs, so I will hunt for another prop to try.
cheers
blaze
You got a ski boat Blaze
What is your gear ratio?
I reco you are right regarding prop choices, you could get that new one cupped. Have you ran any slip numbers to see where you are at? Its definatly traveling too slow for the rpms you are running, not suitable for a fishing rig.nq
the prop I am on ATM is second hand and the only thing it will cost is a little bit of sign writing on a ute, end up about $5.00 and a little bit of time. I will keep chasing another prop to try (nice to get another for the same sorta deal). thinking about leaving this one on for a trip next week, trolling, start trolling in 100m about a 1km from ramp and head to the shelf or there abouts, about 30km out. Gets a little rugged and the extra power may be a benifit.
The gear ratio is 2.07:1
cheers
blaze
Hi Blaze that prop was a bargain, I ran your numbers also but got slightly different I got 0.1570, just multiply by 100 for % so 15.7% slip which is still fairly high. Has that prop been filed? or it might be a very low cup compared to your last one because it should have a heap of extra surface area per inch of pitch over your old one being 3/4 inch wider overall, possibly more cup would help I dunno, good luck with a marlin? (you will have to polish your prop ) nq
PS you may allready know but a general rule of thumb is:
1 inch larger diameter = 2inches extra pitch and a typical cup job = 1 inch extra pitch. cheers
NQ
have ya had a go at cupping a prop, figure that if a template was cut after the first blade is cupped they would be pretty close for a test, whats your thoughts
cheers
blaze
ps
any other comments also welcome
I kwow
just hit it with a BIGGER hammer
Blaze do it!! I love experiments. I have only taken dings out so I could follow the general shape either side of the job.
You have some resin and chop strand, would make a good original template and after cup comparison template.
Although how much cup on prop = 1 inch screwing through the water with 0 slip? Good luck with it if you give it a go. Take some photos cheers nq
) nq
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