Stopcocks on Launching

[pinnache]

Hi there, the previous owner of my boat has just contacted me to say that I should close the head stopcock on launching my boat this weekend. Is there any reason you can think why he would advise this?

[donradcliffe]

If you have never had the boat in the water since you bought it, it might be a good idea to close all but the engine stopcocks before launch, but otherwise its probably not necessary. You might ask the PO why he advised closing the head stopcock--does he know of a problem with the head which might better be fixed before launch??

[swagman]

You profile does not say what type / size of boat you have bought.
But if launching at speed from a trailer, then an open seacock could see a fountain effect down below!
If a regular launch from a crane / lifter, then I can't seriously think why he's worried. But if he is, perhaps worth following his advice.
JOHN

[sabray]

I usually have the lift operator leave the slings below the boat while I check the bilges. A leftover habit from the days of wood. Last launch I had a bit of water come in from the stuffing box and they waited until I had it set proper. seems prudent to close the sea cocks though.

[pinnache]

Hi there was speaking to my seller from Protugal today and he said that nothing wrong with head, just some friendly advice re stopcocks on heads in general manner. He simply said that it was good advice to generally turn off the stopcocks for the head unless it was actually being used and that there was nothing wrong with the head.

He suggested that a stopcock may siphon water into the head if left open when the boat is in the water.

What do you think?

[pinnache]

Originally Posted by swagman

You profile does not say what type / size of boat you have bought.
JOHN

I have a hunter 701 23ft fin keel GRP hull Lead keel on a converted yard cradle now with wheels, will attempt a trailer launch at the local slipway this Saturday with a tractor...If this doesn't work out ( we have alot of sand and littel depth and I draw 4ft) I will pull out and reposition for a crane drop next week

CJ

[denverd0n]

Originally Posted by pinnache

He suggested that a stopcock may siphon water into the head if left open when the boat is in the water. What do you think?

If the head is properly installed, with an anti-siphon loop and vent, then this should not be a problem. Sounds like you need to take a look at how the head is plumbed.

[boatman61]

I'd suggest you close every single stop cock on the boat... then while its still in the slings go round turning them on one by one... there have been occasions in the past when a stop cock has not actually been attatched to anything....
Saves a panic dash round trying to figure out where the waters coming from... hell the price they're charging for the launch more than justifies the extra 15 minutes while you check your water tightness

[thinwater]

Originally Posted by boatman61

I'd suggest you close every single stop cock on the boat... then while its still in the slings go round turning them on one by one... there have been occasions in the past when a stop cock has not actually been attatched to anything....
Saves a panic dash round trying to figure out where the waters coming from... hell the price they're charging for the launch more than justifies the extra 15 minutes while you check your water tightness

Yup, my yard always requests this, and they will always do that if the owner is not present. They always perform a bilge check. Just smart practice.

Also, leaving valves open is an excelent way to grow barnacles in the hoses. Best to shut them when not in use.

[jackdale]

Originally Posted by denverd0n

If the head is properly installed, with an anti-siphon loop and vent, then this should not be a problem. Sounds like you need to take a look at how the head is plumbed.

Anti-siphoning loops are a "fairly" recent development.

That being said, close all the seacocks with the exception of the raw water intake. You may need to start the engine quickly after the boat is in the water.

[zeehag]

Originally Posted by jackdale

Anti-siphoning loops are a "fairly" recent development.

That being said, close all the seacocks with the exception of the raw water intake. You may need to start the engine quickly after the boat is in the water.

funny you should say this about anti siphoning loop vents, as all my boats always had them-- from 1965 on forward to this date-- how recent are you discussing here for the introduction of these recent developments?/ is 40 yrs recent?? just wondering, as i cant figger out how many years is recent...means a different thing to each and every reader, seems.....

and, yes, is a good thing to make sure they are closed before introducing water to hull.

[jackdale]

Zeehag

I used to sail a 1984 C&C 35 that did not have anti-siphoning loops in the head intake. A friend discovered this when he forgot to close the flush lever.

[zeehag]

Originally Posted by jackdale

Zeehag

I used to sail a 1984 C&C 35 that did not have anti-siphoning loops in the head intake. A friend discovered this when he forgot to close the flush lever.

wow--didnt know that recently there werent any -- so , being out of the loop isnt always a good thing...blug.. yipes....
my formosa didnt have one until i placed one just 2 yrs ago--i thought the restorer forgot to replace them......but my 1965 derelict olympian had them..... so i didnt realize there was a time when, in recent past....there really werent any planned into the design...

[Weyalan]

In some cases, the actual bowl is below the level of the waterline and, unless a raised loop (above the w/l) and vacuum breaker is fitted on the water inlet, water can siphon in.

But, as has been pointed out, closing all seackocks when re-launching, is prident anyway. Open them 1 at a time, and check each is watertight prior to opening the next one.