Waterlocks

[MMNETSEA]

Greetings,

Looking for formula to determine correct size of a waterlock .

Known data :- Engine diesel 67 HP - Outlet diameter of wet exhaust 60 mm (2 1/2 ")

Engine manifold above water line. Finally exhausts through transom 75mm above waterline.

a) What is minimum recommended CC capacity for the Waterlock ?

What size inlet/outlet pipes of Waterlock ?

Richard

[Harbor_Pilot]

Originally Posted by MMNETSEA

Greetings,

Looking for formula to determine correct size of a waterlock .

Known data :- Engine diesel 67 HP - Outlet diameter of wet exhaust 60 mm (2 1/2 ")

Engine manifold above water line. Finally exhausts through transom 75mm above waterline.

a) What is minimum recommended CC capacity for the Waterlock ?

What size inlet/outlet pipes of Waterlock ?

Richard

Your question appears to be a problem solved by physics, in the hydraulic discipline, but I do not know what a "water lock" is, or what you want it to do in "I assume" your engine cooling system.

Be more specific please.

[Auzzee]

Hi Richard. I guess every yachtsman knows what a waterlock is and I expect many have not replied for the same reason as me. That is, I am unfamiliar with above the waterline fitment. I have just looked in the West Marine catalogue and at first glance, it appears that a waterlock is unnecessary if everything is over waterline. The suggestion is to fit a wet muffler and an exhaust flapper valve.

However, being a keelboat man, I would probably still fit a lock in the lowest part of the hull, and maybe fit an anti-syphon loop. I think the placement of the waterlock will be vital as, if it is not low enough, and not on the centreline, you could still hydraulise the piston bore from the muffler water reservoir alone. The WM catalogue gives basic data of requirements for both gas and diesel engines.

I assume you are using diesel. So, they say 50 to 75hp requires a waterlock connection of 3 to 3 1/2 inches.

Look on the WM website (westmarine.com) and search 'Exhaust System Basics'. They will also respond to specific questions if you need more.....

Hope this is of some help.

Cheers

David.

[MMNETSEA]

Originally Posted by Aqua Man

Your question appears to be a problem solved by physics, in the hydraulic discipline, but I do not know what a "water lock" is, or what you want it to do in "I assume" your engine cooling system.

Be more specific please.

Check Google for waterlock (not water lock) in the exhaust process (not cooling)

[MMNETSEA]

Originally Posted by Auzzee

Hi Richard. I guess every yachtsman knows what a waterlock is and I expect many have not replied for the same reason as me. That is, I am unfamiliar with above the waterline fitment. I have just looked in the West Marine catalogue and at first glance, it appears that a waterlock is unnecessary if everything is over waterline. The suggestion is to fit a wet muffler and an exhaust flapper valve.

However, being a keelboat man, I would probably still fit a lock in the lowest part of the hull, and maybe fit an anti-syphon loop. I think the placement of the waterlock will be vital as, if it is not low enough, and not on the centreline, you could still hydraulise the piston bore from the muffler water reservoir alone. The WM catalogue gives basic data of requirements for both gas and diesel engines.

I assume you are using diesel. So, they say 50 to 75hp requires a waterlock connection of 3 to 3 1/2 inches.

Look on the WM website (westmarine.com) and search 'Exhaust System Basics'. They will also respond to specific questions if you need more.....

Hope this is of some help.

Cheers

David.

-------------------------------------------------------

Hi David,

It is only the outlet of the exhaust manifold that is above the water line , the rest of the engine is below the water line . I cannot fit the waterlock at the lowest point (engine/propshaft take up the space) The cubic capacity of the lock is important in so far as the bigger one provides less chance of back flow.

Thanks for the response as always.

Richard

PS . I have not had sufficient coffee at time of writing - I could not find WM's Exhaust system basics - pm ?

[Auzzee]

Hi Richard,

I may have overdosed on the caffein when I posted my original reply. If you go to West Marine's home page (westmarine.com), you will see on the titles line, the heading 'Product Advice'. In the drop down menu from that heading is

'West Advisor'. Click on that, scroll down to Engine Systems, and look in the index and you will see Exhaust System Basics. If that is not sufficient, go to the interactive advisor on the same drop down menu and ask for a response to your waterlock question.

I recommend you request a copy of their catalogue, it's free, can be ordered online, and is the size of a small phone book. Apart from being a good marine (Oh-my-god-I-think-it-must-be-Christmas) catalogue, it is 'chockers' with really good advice.

Cheers

David.