jellyfish in gen strainer..urban myth?
I am guessing this is a strong possibility... the other day we were sitting at anchor near pensacola fl. I turned on the gen and it ran fine with normal amount of cooling water ejecting out the side of the boat for about two hours. We were in an area with a good tidal flow and lots of jellyfish were drifting by us. At the two hour make I noticed the cooling water had slowed significantly. Gen had not shutoff due to over heat but I quickly shut it down. I returned to my nearby pier and have not tried the gen again... yet... Question: if it were jellyfish what should I have done to clear the problem?
To be honest I suspect the impeller malfuntioned. .. but would like to know the jellyfish answer.
Sent from Yahoo Mail on Android
Jim:
In the late summer the Chesapeake can turn into the land of the
jellyfish. After 30 years of boating here I have several observations.
If you open your strainers when you are using the generator or AC you
will find jellyfish. If you don't use the generator or AC for a few days
they seem to die and turn to something that goes through the strainers
and disappear on their own. Lots of boaters remove the strainer screens
and are successful but I have kept mine.
The best defense is a large diameter strainer cover over the through
hull. The bigger the better. Do 8" ones if you can. The theory is that
if you provide a larger area for the intake, the jelly fish will not get
sucked into the strainer. Here is a link to the kind of cover I am
talking about: http://tinyurl.com/nn7ubns
These big screens keep my strainers free of nettles all summer.
Frank Burrows 79 43' Viking Piney Narrows Chesapeake Bay
I partially answered my own question... I ran the gen this morning and it ran fine with normal amount of cooling water exiting the boat..... I have not looked inside the strainer with basket inside the hull of the boat for jellyfish residue... I suspect I will not find any.....
I suspect a jellyfish got sucked onto the exterior strainer (the plate with holes on the exterior bottom of the boat) and never disintegrated and entered the strainer/basket inside the boat. When I turned off the gen and got underway yesterday evening, it "fell off" ...
My question now is: If a jellyfish basically shutdown my gen after two hours of run time, what were my chances of making it through the night with an operating gen and air conditioner?
Or better phased, if jellyfish are very thick, should I forgo cruising in hot/humid weather until they clear?
Jim Gano
| I am guessing this is a strong possibility... the other day we were sitting at anchor near pensacola fl. I turned on the gen and it ran fine with normal amount of cooling water ejecting out the side of the boat for about two hours. We were in an area with a good tidal flow and lots of jellyfish were drifting by us. At the two hour make I noticed the cooling water had slowed significantly. Gen had not shutoff due to over heat but I quickly shut it down. I returned to my nearby pier and have not tried the gen again... yet... Question: if it were jellyfish what should I have done to clear the problem?
To be honest I suspect the impeller malfuntioned. .. but would like to know the jellyfish answer.
|
The product you displayed on http://tinyurl.com/nn7ubns looks like it might work, at least better than my thru hull covering which is slotted.
Couple of years ago in Solomons Island, MD, at a marina dock, every tidal change I was getting jelly fish/sea nettles sucked into our strainer. AC would shut down. The best solution for me was to remove the top of the strainer housing and clean out the jelly in the strainer. I also took a hose from the dock and inserted it into the hose from the thru hull to the strainer, tightened a hose clamp around the metal end of the hose and turned on the water. The water pressure flushed out any remaining "stuff" that got last the thru hull and had not reached the strainer.
Since then, it has happened once last summer and just last week as the jellies finally are reappearing in our part of the bay.
Steve
Steve Bedford
Willard 40 FBS
maxmarineproducts.com
Home of the Super MAX Anchor
Burgess, VA
Sent from my iPad. Please excuse misused words due to the "auto correct" function.
On Aug 12, 2015, at 11:11 AM, Frank Burrows via Trawlers-and-Trawlering trawlers@lists.trawlering.com wrote:
Jim:
In the late summer the Chesapeake can turn into the land of the jellyfish. After 30 years of boating here I have several observations. If you open your strainers when you are using the generator or AC you will find jellyfish. If you don't use the generator or AC for a few days they seem to die and turn to something that goes through the strainers and disappear on their own. Lots of boaters remove the strainer screens and are successful but I have kept mine.
The best defense is a large diameter strainer cover over the through hull. The bigger the better. Do 8" ones if you can. The theory is that if you provide a larger area for the intake, the jelly fish will not get sucked into the strainer. Here is a link to the kind of cover I am talking about: http://tinyurl.com/nn7ubns
These big screens keep my strainers free of nettles all summer.
Frank Burrows 79 43' Viking Piney Narrows Chesapeake Bay
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Requires some rigging and glass work but is a fix. Install a sea chest 9"X9"column to above waterline for raw water intakes (obviously below the waterline). The sea chest intake is flush with bottom of the boat using a stainless steel/bronze plate with 1/8' perforations. The much larger opening great reduces suction and any movement of boat or water(current) sloughs off jellyfish. In 8 years never a raw water intake stoppage except impellers or belt.
Joe Pica
M/V Carolyn Ann GH N-37
http://carolynann-n37.blogspot.com/
MTOA#3813, AGLCA #5485
On Aug 12, 2015, at 12:21 PM, Jim Gano via Trawlers-and-Trawlering trawlers@lists.trawlering.com wrote:
I partially answered my own question... I ran the gen this morning and it ran fine with normal amount of cooling water exiting the boat..... I have not looked inside the strainer with basket inside the hull of the boat for jellyfish residue... I suspect I will not find any.....
I suspect a jellyfish got sucked onto the exterior strainer (the plate with holes on the exterior bottom of the boat) and never disintegrated and entered the strainer/basket inside the boat. When I turned off the gen and got underway yesterday evening, it "fell off" ...
My question now is: If a jellyfish basically shutdown my gen after two hours of run time, what were my chances of making it through the night with an operating gen and air conditioner?
Or better phased, if jellyfish are very thick, should I forgo cruising in hot/humid weather until they clear?
Jim Gano
| I am guessing this is a strong possibility... the other day we were sitting at anchor near pensacola fl. I turned on the gen and it ran fine with normal amount of cooling water ejecting out the side of the boat for about two hours. We were in an area with a good tidal flow and lots of jellyfish were drifting by us. At the two hour make I noticed the cooling water had slowed significantly. Gen had not shutoff due to over heat but I quickly shut it down. I returned to my nearby pier and have not tried the gen again... yet... Question: if it were jellyfish what should I have done to clear the problem?
To be honest I suspect the impeller malfuntioned. .. but would like to know the jellyfish answer.
|
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