[[Image:Rota_sludge_well_drilling_icon.png|right]]
The Rota-sludge method is an adaptation of the Indian hand sludge method. The hardened drill bit is turned 90 degrees during drilling thus chiselling the bottom of the hole. This technology can be used to drill 2-5 inch wells in layers with sand, clay, gravel, tuff stone or weathered rock.
[[Image:Rota_sludge_well_drilling.PNG|thumb|right|150px|Drilling a 20 m deep well in Chinandega, Nicaragua, with the Rota-sludge method ]]
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdead;" | Disadvantages
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| valign="top" | Drills in hard soils.<br>
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== Capacity ==
40 litres / min from 10 meters depth.
== Costs ==
* US$ 20-120 depending on model.
== Applying conditions ==
<ul>
<li><b>Numbers:</b> 50,000 in Nicaragua, 20,000 in Mexico, Honduras, Guatemala, Ghana, Zimbabwe, Tanaznia, Senegal.</li>
<li><b>Range of depth:</b> 1-35 meter (60 m with two cranks).</li>
<li><b>Application</b> Communal wells, houshold, irrigation. </li>
<li><b>Cost of introduction:</b> US$ 10,000-20,000 per project, including 20 pumps, engineering and hands-on training. US$ 60,000-100,000 per project, including 1,000 pumps, production workshop and hands-on training.</li>
</ul>
== Rope pump building manual ==
PRACTICA foundation and the Technical Training Programme of the ETC Foundation (TTP/ETC) have put together a really [http://www.greenocean.org/akvo/PRACTICA_180306_Rope_pump_manual_Ethiopia_March_2006_complete.pdf excellent manual on how to build rope pumps] (PDF, 2.5 Mbyte). It is an 86 page long document with detailed instructions.
== External links ==
* Evaluations [http://www.irc.nl www.irc.nl ]
* Africa [http://www.pumpaid.org www.pumpaid.org ]
* General info [http://www.ropepump.com www.ropepump.com]
* How to build [http://www.ropepumps.org www.ropepumps.org]