Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-06-2010, 18:18   #16
Senior Cruiser
 
Sailmonkey's Avatar

Cruisers Forum Supporter

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 5,775
It's just gas after the box, but is wet to the box. The exh from the engine will still mix with water, then exit the waterlift to an undisclosed location above the waterline where the magic of the box works. After that point it can go up/down/left/right so long as the drain line goes down and out (as short as possible and above the waterline so you can see the water). I should also mention that the drain line needs to be larger than your water supply to the engine, say 1 1/4" for a 3/4" supply.

The one I built was made of 1/8" doorskins for a basic shape, except for the bottom. I built it of epoxy and glass mat inside and out (more inside) then adden the three fiberglass pipes and base at the bottom, but used all mat and cloth for this part. Worked like a charm and I hope is still working to this day.
__________________

__________________
Sailmonkey is online now   Reply With Quote
Old 14-06-2010, 21:37   #17
Registered User

Join Date: Mar 2007
Location: Brisbane
Boat: s/v Sildene
Posts: 91
Water volume

Quote:
Originally Posted by akio.kanemoto View Post
Howdy,

Also - something else that has been bothering me is that the exhaust run is all uphill until the gooseneck which will be just short of the outlet. I have a vetus waterlock which the specs say holds 5L.. exactly how much of the hose is filled with water? Definitely not 100%, but how little? The reason I ask is that when the engine is stopped, all the water in the hose will run back and fill the waterlock... looking at the exhaust run - I would have guessed that the hose would contain more than 5L and thus will fill the waterlock and fill the exhaust manifold etc... Thoughts?
I once had a fibreglass muffler made for a 16 foot wet line. Reading my old notes, the muffler fabricator was happy with my calculating the max liquid flow-back volume based on 25-30% of the line's air volume.

Martin
__________________

__________________
sildene is offline   Reply With Quote
Old 14-06-2010, 21:52   #18
Registered User

Join Date: Mar 2009
Location: Sydney
Boat: Lexcen 40 - Leverage
Posts: 383
Quote:
Originally Posted by sildene View Post
I once had a fibreglass muffler made for a 16 foot wet line. Reading my old notes, the muffler fabricator was happy with my calculating the max liquid flow-back volume based on 25-30% of the line's air volume.

Martin
Thanks muchly - that's perfect.
__________________
akio.kanemoto is offline   Reply With Quote
Old 15-06-2010, 04:43   #19
Registered User

Join Date: Jun 2005
Posts: 1,901
Quote:
Originally Posted by akio.kanemoto View Post
Also - something else that has been bothering me is that the exhaust run is all uphill until the gooseneck which will be just short of the outlet. I have a vetus waterlock which the specs say holds 5L.. exactly how much of the hose is filled with water? Definitely not 100%, but how little? The reason I ask is that when the engine is stopped, all the water in the hose will run back and fill the waterlock... looking at the exhaust run - I would have guessed that the hose would contain more than 5L and thus will fill the waterlock and fill the exhaust manifold etc... Thoughts?
Add the Vetus goodneck at the transom, or skip it and install a flap door on the outside. It's purpose is to keep following seas out.
The water travels up the hose in a layer against the side, not a slug between air pulses. A 5L water lock "might" be enough for that long of a run. If you could upsize it, it wouldn't hurt.

If your still having concerns about back pressure. Make the exhaust system out of 3" hose instead of the 2" normally on a GM series.
__________________
never monday is offline   Reply With Quote
Old 15-06-2010, 10:13   #20
Registered User
 
cdennyb's Avatar

Join Date: Jun 2007
Location: Northern California
Boat: finally a catamaran dive boat...
Posts: 505
Send a message via MSN to cdennyb Send a message via Yahoo to cdennyb Send a message via Skype™ to cdennyb
.445 psi is what the pressure is of a water column, take a pipe or hose or whatever and hold it up vertically. If it's 6' long and full of water then the pressure at the bottom is .44 x #of feet (6) = 2.67 in a perfect world. Just thought you'd like to know the pressure to overcome, it is a vertical component and does not take into consideration the loops, bends, restrictions, etc. of your tube run.
__________________

__________________
the perfect dive boat is one you're on...
cdennyb is offline   Reply With Quote
Reply

Tags
3gm, 3gm30, yanmar

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 3gm30 Water Pump Jacana Engines and Propulsion Systems 16 26-09-2010 07:10
For Sale: Yanmar 3GM30 ringmiller Classifieds Archive 1 16-03-2010 14:56
FS: Yanmar 3GM30 2500hrs sailnw777 Classifieds Archive 1 14-05-2009 20:19
Yanmar 3gm30. Jacana Engines and Propulsion Systems 4 19-03-2008 10:14
Exhaust Outlet Height Kai Nui Engines and Propulsion Systems 13 01-02-2006 13:39



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:07.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.