Boat nappy

TiggerToo

TiggerToo

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Last weekend, I dived under the hull of Tigger to remove some of the "slime" that had built up around the log impeller - the slime caused the impeller to under-read by about 25% (i.e. showed 3kn compared to 4kn on the GPS (NB no tide). Once the hull was cleaned, the impeller was back to "proper" speed.

It got me wondering.

How about constructing a sort of "boat nappy", made up of some dark canvas, stretched over the area around the impeller (held in place by a couple of strings) when the boat is moored for long periods? This could then be removed just before leaving. Just cleaning the impeller is not good enough, as the flow of the water around it is clearly impaired by the slime.

Has anyone tried this? Can anyone think of any problems?
 
TiggerToo said:
Last weekend, I dived under the hull of Tigger to remove some of the "slime" that had built up around the log impeller - the slime caused the impeller to under-read by about 25% (i.e. showed 3kn compared to 4kn on the GPS (NB no tide). Once the hull was cleaned, the impeller was back to "proper" speed.

It got me wondering.

How about constructing a sort of "boat nappy", made up of some dark canvas, stretched over the area around the impeller (held in place by a couple of strings) when the boat is moored for long periods? This could then be removed just before leaving. Just cleaning the impeller is not good enough, as the flow of the water around it is clearly impaired by the slime.

Has anyone tried this? Can anyone think of any problems?
Click to expand...

Once you take your strap of sodden wet, minging, barnacle ridden canvas off - where are you going to put it?

I swap out the impeller for the cap at the end of each sail. Takes 30s to do...
 
Guys, guys... I have been doing the cleaning of the impeller trick for as long as I have had the boat. Actually, more recently (since giving up chartering) I have "religiously" removed the impeller at the end of a cruise and placed the "Bung" in. Some mopping is always needed.

But this is SOMETHING ELSE (I see that I did not make myself clear in the OP). The (thin) layer of slime AROUND the impeller area appears to create a thicker "boundary layer" which slows down the flow over the impeller, however clean the paddles are.

My suggestion about the "hull nappy" was to keep a larger area slime-poor, so that the boundary layer around the impeller is reduced.
 
TiggerToo said:
How about constructing a sort of "boat nappy", made up of some dark canvas, stretched over the area around the impeller (held in place by a couple of strings) when the boat is moored for long periods? This could then be removed just before leaving. Just cleaning the impeller is not good enough, as the flow of the water around it is clearly impaired by the slime.

Has anyone tried this? Can anyone think of any problems?
Click to expand...

Your "nappy" idea should work just fine. Only downside is, you now have a slimy piece of canvas to leave somewhere when you go sail :)

Or just use a piece of old carpet and pull it back and forth a couple times to clean the hull in front of the impeller. Or more :)
 
It is no more trouble for me to withdraw the impeller under way than when berthed, so I usually leave it down and clean it when it needs it. It was thick with weed the other week, which is unusual a this time of the year for me.

Personally, I would like a whole-boat nappy, preferably enclosing genetically-modified grey mullet trained to nibble away at the weed.
 
A piece of old carpet sound like the best idea - that would conform easily to the hull and the log impeller would 'sink in' to the pile. No need to bring it aboard - just tow it behind to give it a good rinse! I would suggest that you really need to deal with the whole slime problem - It really slows my boat down, despite being just 'slime'. Seeing the log displaying a speed a knot and a half less than it should, for me, means the boat is going a knot and a half slow. £20 for the scrubblng piles in Chi!
 
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I have tried the idea of a huge nappy for the whole hull. It works well both excluding sun light and also concentrating the anti foul chemicals that come out of the paint. It minimised slime and weed build up where normally fouling is really bad. (warm water lots of sun) (Think your recent heat wave for 4 months every year.)
The nappy was made of poly tarp and pulled up around the hull. When I departed for a sail the nappy was left attached to the swing mooring. But ultimately it was just too much trouble to back out of the nappy and then attach it again on return. At least one 30ft mobo uses one in our club marina. He actually pumps water out of the nappy once attached. So really good if you leave the boat for long periods with no use but a pain for the frequent short sails. ol'will
 
If you use good AF and use your yacht sufficiently frequently then you do not get slime. If you use your yacht infrequently you are wasting money and should simply charter when you want to go for a sail :)

Jonathan
 
Nappies, boat sized, are quite common (and as mentioned at the beginning of the thread) and hardly a new idea. An alternative is to have a cradle that lifts your yacht out of the water - think inflatable (deflated) that you drive into and then pump up.

Even better if your paid hands do it for you.

I'm sure that with virtual reality you can enjoy all the pleasures of sailing (without any cold, wet, or hot and UV) from the comfort of you home if real life is too much. It will not be too long and Concerto's exploits round Britain will have all the hot, cold, wet and dry - electronically - and we will not even to read any of it.....what will YBW do then



Jonathan

:sick:
 
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