andy_iw
New Member
My Friend Recently Started Having problems with his feathering 3 blade prop in reverse, it works perfectly fine in ahead but when put in reverse it seems to overload the engine with little affect!
feathering prop problem
- Thread starter andy_iw
- Start date
alan
Well-Known Member
Probably blades not opening to correct ptch or not opening at all ? Could be due to heavy fouling ??
Alan.
Alan.
mobeydick
Well-Known Member
what make of prop?
savageseadog
Well-Known Member
Is it a Kiwiprop?
One reason could be that the engine is cooler (it's winter!) and will tend to develop less power until warm.
One reason could be that the engine is cooler (it's winter!) and will tend to develop less power until warm.
andy_iw
New Member
its not the engine even once warmed to a decent temp it still plays up but only in reverse not in ahead! Which makes me feel the prop is fouled in away where in reverse the prop cant open properly
andy_iw
New Member
Could it be a problem with one of the variable pitch screws?
FullCircle
Well-Known Member
if its a Kiwiprop in a muddy water area, its likely that the reverse mech is jammed by fouling on the bearing plates. You need to disassemble it, clean it thoroughly, reassemble with LOADS of grease, and then anti foul the outside with something like trilux.
Mine does this 2/3 of the way through the season on the River Crouch. Harumph.
It does help if reverse is engaged and used frequently. Mine isnt as I live on a swingging mooring, so dont need reverse normally.
Mine does this 2/3 of the way through the season on the River Crouch. Harumph.
It does help if reverse is engaged and used frequently. Mine isnt as I live on a swingging mooring, so dont need reverse normally.
andy_iw
New Member
ok thanks will check that out am gonna check the gearbox aswell as it might be something in there havent seen it yet got a call from my friend this morning so will just eliminate all options whilst still in the water then get it lifted and carry on then thank you
davidbains
Well-Known Member
The pitch is much coarser in reverse on Kiwi props which is great as long as your gearbox has a higher ratio in reverse. Also it helps to set the tick over speed a bit higher, and use some throttle in reverse! It could well be as FullCircle says that the reverse spring mechanism is not fully setting the reverse pitch due to internal or external fouling. Also the prop has several grease points which need attention with a powerful grease gun with a fine nozzle, obtaiable from the UK Kiwi suppliers.
charles_reed
Well-Known Member
Reverse in most gearboxes
Is a lower ratio than forward, meaning the engine goes round more times than in forward to 1 rotation of the prop.
My guess is that 1 or more of the blades is getting to the "flat" position ie fore&aft and jamming there.
I've had it once, on my feathering prop - that was in forward gear - and cleared it by repeated application of forward and reverse whilst moored.
My assumption was that it was due to fouling.
Fixed props are definitely less efficient and produce greater drag in reverse - this is not the case with self-feathering props, where the blades rotate through 180°.
I find the contention that Kiwi props "are coaser in reverse" to be lacking in credibility, but am willing to stand corrected if any objective evidence (say from the Kiwi site) can b°rodued.
Is a lower ratio than forward, meaning the engine goes round more times than in forward to 1 rotation of the prop.
My guess is that 1 or more of the blades is getting to the "flat" position ie fore&aft and jamming there.
I've had it once, on my feathering prop - that was in forward gear - and cleared it by repeated application of forward and reverse whilst moored.
My assumption was that it was due to fouling.
Fixed props are definitely less efficient and produce greater drag in reverse - this is not the case with self-feathering props, where the blades rotate through 180°.
I find the contention that Kiwi props "are coaser in reverse" to be lacking in credibility, but am willing to stand corrected if any objective evidence (say from the Kiwi site) can b°rodued.
vyv_cox
Well-Known Member
Re: Reverse in most gearboxes
Many possible reasons are given on the Kiwi site http://www.kiwiprops.co.nz/reversing.html although we still don't know whether it is a Kiwi or not. Interesting that they publish such a list: it would seem that there is a real problem in this area. Nothing similar on the Brunton's site!
Many possible reasons are given on the Kiwi site http://www.kiwiprops.co.nz/reversing.html although we still don't know whether it is a Kiwi or not. Interesting that they publish such a list: it would seem that there is a real problem in this area. Nothing similar on the Brunton's site!
PeterGibbs
Well-Known Member
Re: Reverse in most gearboxes
Wow, sort of feeling good about my sturdy fixed 3 blader - but no one wants to hear its virtues so I'll just wait for the penny to drop....
PWG
Wow, sort of feeling good about my sturdy fixed 3 blader - but no one wants to hear its virtues so I'll just wait for the penny to drop....
PWG
DaveS
Well-Known Member
Re: Reverse in most gearboxes
Well, for a motor boat a fixed prob is just fine. Many of us who sail have, however, found a feathering prob to have significantly less drag, letting us sail faster.
Well, for a motor boat a fixed prob is just fine. Many of us who sail have, however, found a feathering prob to have significantly less drag, letting us sail faster.
