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Trouble shooting offshore

Posted: Aug 24th, '06, 06:27
by Ric
6 weeks ago I was offshore and i had an incident. An exhaust idiot light and an audible alarm was intermittant and chirping and blinking in and out. indicating a problem with raw water, I had throttled down from cruise as i seen something (fishy water) and decided to check it out, when i throttled back up to take off the alarm went off, the starboard engine would not go more than idle speed or it would sound. I imediately thought Pump, but i had just rebuilt them, I go to the step where sea strainers are located and "shut" seacock and take cover off of sea strainer and pull the screen out of sea strainer,,nothing ,a little weed but no biggie, put it back open sea cock I pull a hose off of raw water side near exhaust and i have just a little water, enough, but not right..,., Sheeat ,,,I'm 22 miles offshore I punch up the northstar 6 hours at 8 knots 1 engine and the starboard at idle.,.,whew,,,,,,,,,,,,,,,,,I get back to the dock and start taking out the pump i CALL MY "GUY" who built the boat with me and he said why did u take off the pump? I said because thats where i think the problem is he says I dont think so (,,,from the phone,), it takes 2 guys to put the pump "back" in 1 to get the gear to gear lined up and 1 guy hanging over the motor to turn the flywheel with a wrench,,,,,,so he comes down to the dock its 9 p.m. Looks at the pump nothing wrong with it, we rebuild it again ,,its out its apart, we are not ,not going to replace the impellar ,,so we put it back in, pull the hose on the other side of the pump and still no water very little,,.,.,open up the sea strainers both of them, (leave sea cocks open), port side starts trying to sink the boat but starboard very little water,,Thats where the trouble is ,between the thru hull and the 90 sweep on the sea strainer 14 inches of hose and nipples,,,,, what ever it was we didnt see it,,, I couldnt dive under the boat and stick a coat hangar up there it was 9;30 at night .,.,,. I have no scoops on thru hull just straight holes,,, so we took a garden hose washdown (on the) dock
stuck it into the top of of sea strainer in the 90 sweep and stuffed rags arround the opening to build pressure and it blew out the bottom,,and i was( back in business) 8) it was so small it got into the hole in thruhull but not into the sea strainer and when i powered up it FLAPPED over to create a dam and would not let sea water into the sea strainer and pump :roll: ...,.,.. 6 hours to get in, rebuild pump for nothing,
if innitially while at sea I left the sea cock open when i checked the sea strainer i would have noticed no Water trying to sink the boat (MAYBE) and found the problem was between the hull and the 14 inches of 1 1/2 inch hose .,..,I dont know if my washdown would have been enough pressure to blow it out the bottom.,., but i would have liked to try.,.,.,.,.,.,unbelievable,,,, very unusual,, but hey!

Posted: Aug 24th, '06, 07:12
by CaptPatrick
Ric,

Perfect example of why external strainers are the way to go...

Image
External Raw Water Strainers


Br,

Patrick

Posted: Aug 24th, '06, 09:48
by capy
Ric,

I had something similar hapen about 9 years ago.........I dove and found a plastic grocery bag sucked into the slots of the external strainer.

It hapened twice since then but instead of diving, I just back down real hard and the prop wash strips the crap from the strainer.

Posted: Aug 24th, '06, 13:18
by Bruce
Try stabilizers.

Lets you hold an aim better.

Posted: Aug 24th, '06, 13:46
by Charlie J
south bay strainers are primarily used on long island, due to the amount of eel grass, same as the groco but with out the hinge