The S&S34 cockpit drains go through a hose to seacocks below the cockpit. I had new cocks and hoses installed about 6 years ago.
The port one has had a persistent small leak from the cockpit drain ever since. It has only been an annoying leak and it finally got to the top of the priority list. Last week I took the hose off the cockpit drain fitting and found the hose had a small split in it.
I bought a metre of hose from Whitworths and this morning went down to install it. Afterthe hose was off I found the diameter of the sea cock fitting is slightly smaller than the cockpit drain fitting. The idiot chippie who fitted it couldn't get the hose over the cockpit drain fitting so he had put a small split in the hose to get it on.
Taking the old hose off I found the bottom of the hose and the sea cock fitting almost blocked with barnacle growth. The drain seemed to be draining ok but the amount of growth was surprising. After I scraped out most of the growth I put the new hose on, which is clear, and when I turned the sea cock back on a massive amount of debris floated up.
Needless to say the cockpit drain really gushes now.
I will take the other hose off next week and clean it out.
Most marinas when anti fouling will scrape out the opening up to the sea cock. But cocks that are always open, like a cockpit drain, will form barnacle growth above the cock. Scraping out a sea cock in the water is a bit stressful, there is always a risk you will scrape too hard and damage the cock. I know a yacht sank in Lake Maquarie when a diver doing a hull clean put his scraper up a sea cock opening to clean it out and broke the cock.
The lesson is; when the boat is out of the water take the hoses off all your sea cocks and clean them out.

good talk !! ........... ive found that blasting the cockpit drains with a garden hose ,every now and then does wonders .

It is barnacles or calcium build up if the fitting is very old.
Also can balance change with a change of mooring.
A sparky friend of mine calls Raby Bay Canals, the " North Cleveland Electroplating works"!
sorry just trying to help.

Barnacles in seacocks would be pretty unusual, as they are filter feeders they need pretty good flow to survive. My son and I dived under my boat in January and all through hulls were clear, the prop and shaft now that's a different story they need scrubbing every 3 months.

BlueMoon said..
Could be oysters, I know here on NSW mid nth coast, our river is one of the few that the oysters "self seed" (there's a proper term for it but I can't think of it right now"). I am usually digging small oysters out of the thru-hulls when I clean the bottom.
cheers

+1 Same with mine, Gwawley Bay, Georges river. Little buggers will grow enough to virtually fill the skin fitting.
One other thing, the hose you installed is clear?, does it have any reinforcing material in its construction, I have always been of the understanding that drain hoses should always be heavily reinforced and of the heaviest construction practicable.

UncleBob said..

BlueMoon said..
Could be oysters, I know here on NSW mid nth coast, our river is one of the few that the oysters "self seed" (there's a proper term for it but I can't think of it right now"). I am usually digging small oysters out of the thru-hulls when I clean the bottom.
cheers

+1 Same with mine, Gwawley Bay, Georges river. Little buggers will grow enough to virtually fill the skin fitting.
One other thing, the hose you installed is clear?, does it have any reinforcing material in its construction, I have always been of the understanding that drain hoses should always be heavily reinforced and of the heaviest construction practicable.

It is always in your view, easily accessed and only draining the cockpit, there is no pressure nor suction on it, almost any hose will be ok. This stuff was listed as bilge hose though.
The chippie had used toilet hose which had hardened over time, I will replace these hoses, only $12.50 each, on a regular maintenance schedule to prevent them going hard.

The chemistry of the water could change within a few meters if the source is persisting. I mean a slightly leaking holding tank cock on a boat not far away could cause the chemistry of the water to change, so the different environment would attract different creatures. Barnacles vs. oysters?
I found similar change happening at my mooring which is not far from MB's. Certain creepers never countenanced in the area seem to grow now, others disappearing.

Jolene said..
I usually go for a dive under the boat about once a month to check things out. My below waterline cockpit drains are usually pretty clear, meaning that they have never required attention.
Not liking the idea of below waterline drains, I felt I had to replaced the bilge pump hose that was on them with some heavy rubber stuff and fit some T-Bolt clamps

Best check above the sea cock, I thought mine were clear because they had been cleaned from the outside.

MorningBird said..

Jolene said..
I usually go for a dive under the boat about once a month to check things out. My below waterline cockpit drains are usually pretty clear, meaning that they have never required attention.
Not liking the idea of below waterline drains, I felt I had to replaced the bilge pump hose that was on them with some heavy rubber stuff and fit some T-Bolt clamps

Best check above the sea cock, I thought mine were clear because they had been cleaned from the outside.

Yep there're all clean,,maybe sailing in the ocean every weekend flushes them.

Jolene said..
I usually go for a dive under the boat about once a month to check things out. My below waterline cockpit drains are usually pretty clear, meaning that they have never required attention.
Not liking the idea of below waterline drains, I felt I had to replaced the bilge pump hose that was on them with some heavy rubber stuff and fit some T-Bolt clamps

Nice to see someone using decent quality rubber hoses for a change! If you suspected some shell build up in the hose you could close the ball valve and pour some phosphoric acid mixture in and let it soak for an hour or so. The calcium will dissolve and then you can just flush it clear. I like "Metal Gleam" or you can use a boutique product like Barnacle Buster.

Ramona said..

Jolene said..
I usually go for a dive under the boat about once a month to check things out. My below waterline cockpit drains are usually pretty clear, meaning that they have never required attention.
Not liking the idea of below waterline drains, I felt I had to replaced the bilge pump hose that was on them with some heavy rubber stuff and fit some T-Bolt clamps

Nice to see someone using decent quality rubber hoses for a change! If you suspected some shell build up in the hose you could close the ball valve and pour some phosphoric acid mixture in and let it soak for an hour or so. The calcium will dissolve and then you can just flush it clear. I like "Metal Gleam" or you can use a boutique product like Barnacle Buster.

I took your advise from the forums and changed out all my brand new plastic raw water hoses with the red rubber hose.
The only negative from doing so is that the hose barb fittings designed to grip the plastic pipe are brutal on the rubber. If you fit the rubber hose and then try to remove it, you tear the guts out of the hose or you can't remove it and you have to cut it off. So to solve this problem a made my own new custom fittings with smooth barbs. Old corroded s/steel keel bolts come in handy.

A few of them here next to a plastic hose type s/steel barb