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post #7 of Old 12-21-2012
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Re: Nettles clogging strainer

Your 'sea-chest' is probably SLOWING the water flow (rate) in comparison to the its inlet/outlet. The comparatively higher flow rate in the piping and 'clam shell' strainer is high enough to 'chop up' the nettles, the low flow rate in the 'chest' is allowing or promoting 'packing together' (agglomeration) of the 'gel-like' particles in the low flow rate areas. This 'packing' is quite common with 'gels' and gel-like contaminants where the flow rates speed-up then slow-down, etc.

To 'filter' or 'strain' such 'gels' you need a LARGE surface area 'strainer' so that the gels are removed at first opportunity in the circuit; the LARGE surface area will slow the fluid velocity and prevent 'chop-up' ... but youre going to need an 'easily cleanable' strainer to do this, and for good measure you should install an accurate 'differential pressure switch wired to an alarm' to tell you WHEN to clean out the inlet strainer'.
Other possibility is a 'duplex' strainer one side 'on' while the other side is offline and 'backwashing' the gunk out the 'off side' ... requires another 'hole' in the boat bottom.

Not to worry however, as the infamous zebra mussels are now in the lower Susquehanna basin and the problems that they will cause in the brackish Upper Chesapeake will completely make sucked-up nettles seem like a 'privilege'.

Last edited by RichH; 12-21-2012 at 04:05 PM.
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