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Author Topic: Prop Weed  (Read 1430 times)

Bob K

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Prop Weed
« on: November 01, 2016, 10:19:40 pm »

I don't know about you other Mayhemer's, but at our lake the normally pond-weed free waters have been blighted with the dreaded stuff over the last few weeks.  Sometimes it can bring you to an almost halt within a few metres of launching.  Annoying.

Here is the question:  Why does even a small amount of pond weed completely kill the flow of water over propeller blades?  A loose looking green candyfloss effect that you can clearly see the prop blades through. Lift the boat out of the water and the props spin freely, but in the water they may turn but with zero propulsive effect.  Single 20 mm prop, even twin 45mm props, we are all getting brought to a standstill.

weird  >>:-(
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Colin Bishop

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Re: Prop Weed
« Reply #1 on: November 01, 2016, 11:55:56 pm »

Weed gets round the prop and nullifies the propulsive effect.

Colin
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malcolmfrary

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Re: Prop Weed
« Reply #2 on: November 02, 2016, 08:42:43 am »

The water only "sees" the green candyfloss blob, not the prop blades.  The candyfloss just throws the water outwards,
Sometimes a bit of gentle reverse will unwind it - downside of that is that if the prop is not properly locknutted/threadlocked on, it can unwind the prop.  A weed deflector can be fitted.  These have varying degrees of effectiveness.  My most effective one was an angled wire in front of the prop.
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NFMike

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Re: Prop Weed
« Reply #3 on: November 02, 2016, 09:17:13 am »

It sounds rather like a 'jelly' effect. The weed is just making the water semi-solid, so the prop is not shifting it, just spinning it round. Or possibly it's moving it a bit but it's just going round the blade ends and back into the front of the prop. If the prop doesn't accelerate a significant mass of water you don't get much thrust, and presumably the 'thicker' water is harder to push the boat through too.

imsinking

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Re: Prop Weed
« Reply #4 on: November 02, 2016, 10:08:04 am »

 :-))  Congratulations , you've just joined W.H.A.T.
 %%  Weed Haters Anonymous Team . . .
Sounds like micro algae that's clumping together , you'll need to try to find out whats changed , any tyre  marks near the lake ? . . .  DUMPING , increase in bird population ? the same , algae thrives on guano , once it gets a foothold it takes some shifting, it grows quicker than you can net it out  <:(   
Bill
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BFSMP

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Re: Prop Weed
« Reply #5 on: November 02, 2016, 02:06:12 pm »


I was talking to a couple of members of the Fleetwood club only last Wednesday afternoon, when I sometimes try to get down their to watch the yachtsmen racing their models.


There are 3 lakes at Fleetwood, and all filled with sea water. the large lake closest to the River Wyre end has no problems as it is used constantly by the local Nautical college and a local canoeing cub, plus the local Sea Cadets which keeps waters constantly activated, and as such, no bird population.


However the model yachting pond and the smaller paddling pool at the far end from the club house have in the past been the recipient of this weed. this year however the small paddling pool which has over the years been in constant use from the less brave boaters who don't chance their models in the larger lake has been festooned with the dreaded weed which has virtually brought model sailing to a stand still.


This has not been the case though, with the main model yachting lake, to a great extent.


Some years ago the lake was transposed by hundreds of wild foul and was blanketed by weed.As the lakes are owned by the local council they had to do something with up coming world championship yacht racing, and so researched the problem and came up with the solution to put into the bed of the lake sonic transponders which destroyed the growth of the weed. And it works, as the main lake has been almost totally weed free this year.


Jim.
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Netleyned

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Re: Prop Weed
« Reply #6 on: November 02, 2016, 03:11:02 pm »

I have had no bother since using brushless motors and weedless props


Ned
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Bob K

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Re: Prop Weed
« Reply #7 on: November 02, 2016, 04:07:40 pm »

I was just wondering what was causing this unusual harvest of pond weed.  Normally our big lake hardly ever gets it.  Loads of big fish, including huge pike.  Over 30 feet deep, and lots of wild fowl all year round.

I guess it might be the sudden change in the weather, suddenly cooler after weeks of sunshine.

Has anyone devised a weed clearing boat.  Like a springer tug towing a short boom with weighted net, kind of like a combine harvester.
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Nemo

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Re: Prop Weed
« Reply #8 on: November 02, 2016, 06:01:12 pm »

Bob, just hope some gobby idiot does not mention seeing  Great Crested Newts in your weed or you will not even  be able to clear the stuff- like our club. See other posts , of which there are many!    >:-o
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Bob K

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Re: Prop Weed
« Reply #9 on: November 02, 2016, 07:29:59 pm »

I did follow that thread Nemo  O0
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