Reply
 
Thread Tools Search this Thread Display Modes
 
Old 10-29-2020, 11:27 AM   #41
Guru
 
rgano's Avatar
 
City: Southport, FL near Panama City
Vessel Name: FROLIC
Vessel Model: Mainship 30 Pilot II since 2015. GB-42 1986-2015. Former Unlimited Tonnage Master
Join Date: Oct 2007
Posts: 4,488
The custom 55-foot vessel I delivered over a 1600-mile run last spring had a JD main and two 20 KW gennies, all dry stacked right up behind the pilothouse. The boat deck aft of the pilothouse was filthy with oily soot, and the uncovered dinghy was too dirty to even consider using during our thirty days aboard. The engine had just been gone over by a JD tech including new injectors. At cruise speed I could always see a grey haze from the JD against white clouds.
__________________
Rich Gano
FROLIC (2005 MainShip 30 Pilot II)
Panama City area
rgano is offline   Reply With Quote
Old 10-29-2020, 11:49 AM   #42
Guru
 
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 9,496
Quote:
Originally Posted by Delfin View Post
True dat Tom. Some engines seem better suited for dry stack than others. My CAT 3306 runs quite clean, but if the boat was powered by a 3208 I might feel differently, and if a DD my neighbors might cringe at my approach. I've had to clean soot off the top deck about 10 times in 15 years, and then because I didn't run the boat up to 80% of max RPM for a few minutes to blow out any accumulation of soot before turning into anchorage or a marina. The boat is quiet underway because it is well muffled, and the stack house is well insulated. The system seems pretty much bullet proof, at least so far. As TT said, excess heat from a dry stack seems a matter of not insulating the exhaust in the ER; mine isn't hot enough not to be able to touch.


The genset is hybrid - keel cooled and wet exhaust, and I've cleaned more soot off the side of the vessel where the exhaust loop exits than the top deck.


Converting a wet exhaust system to dry seems a bit pointless as both systems, if designed from scratch, work just fine.
Delfin
The 3306 is such a great engine. As I recall you've taken much effort to insure the vessel is propped correctly. Cruising props, meaning intentionally overloaded, are for some reason a popular thing for our slow trawlers. An overloaded engine would seem a poor choice for a dry stack. Your thoughts?
sunchaser is offline   Reply With Quote
Old 10-29-2020, 12:01 PM   #43
Guru
 
firehoser75's Avatar
 
City: Nanaimo
Vessel Name: former owner of "Pilitak"
Vessel Model: Nordic Tug 37
Join Date: Feb 2018
Posts: 1,627
Quote:
Originally Posted by twistedtree View Post
I'd like to do something like that. How do you have things plumbed up to do the fresh water flush? I think there are lots of ways it could be done, and I'm always interested in examples and how well they work.
I freshwater flush both my engine and generator using the Groco strainer lid. I have a garden hose (with shut offf) attachment permanently affixed to the lid. Connect a dock hose to the strainer and flush with the engine running at idle for about 4-5 minutes. Just don't have the pressurized water running with the engine off without the thru hull open. The sea water intake can be either open, partially open, or closed when flushing.
Attached Thumbnails
Engine Flush System.jpg  
__________________
Tom
Nanaimo, BC
firehoser75 is offline   Reply With Quote
Old 10-29-2020, 12:37 PM   #44
Guru
 
Fish53's Avatar
 
City: Rockport
Vessel Name: Ana
Join Date: Jul 2015
Posts: 1,012
I've worked on and operated commercial trawlers for over forty years and they all had dry exhaust and there has never been a problem. That being said most pleasure boaters don't want exhaust soot on them and there is a noise issue. The complexity of having wet exhaust, the seawater pump and associated plumbing may be an issue to some as is the difficulty of operating in freezing temps. These are reasons I have dry on my personal boat just like the one I currently work on.
Fish53 is offline   Reply With Quote
Old 10-29-2020, 12:42 PM   #45
Guru
 
OldDan1943's Avatar
 
City: Aventura FL
Vessel Name: Kinja
Vessel Model: American Tug 34 #116 2008
Join Date: Oct 2017
Posts: 9,898
Quote:
Originally Posted by firehoser75 View Post
I freshwater flush both my engine and generator using the Groco strainer lid. I have a garden hose (with shut offf) attachment permanently affixed to the lid. Connect a dock hose to the strainer and flush with the engine running at idle for about 4-5 minutes. Just don't have the pressurized water running with the engine off without the thru hull open. The sea water intake can be either open, partially open, or closed when flushing.
You have been peeking at my strainer back flushing caps and you have the same problem I do. BRASS pipe and hose connection instead of bronze. I also use a plastic hose snap gadget. Also a garden hose back-flow preventer. I use the ER FW connection along with the hose I keep coilied on board.
Also, mine is right side up too.

For safety sake, I take mine off when not in use and put the blank cap on.
__________________
The meek will inherit the earth but, the brave will inherit the seas.
OldDan1943 is offline   Reply With Quote
Old 10-29-2020, 03:01 PM   #46
Guru
 
twistedtree's Avatar
 
City: Walkabout Creek
Join Date: Jan 2013
Posts: 8,242
Quote:
Originally Posted by Hippocampus View Post
Been a learning curve looking at small Nordhavns to buy. See some with twin turbo yanmars which are wet exhaust but most with naturally aspirated luggers to a dry stack . The small commercial fish boats around here commonly have truck or agricultural pump diesels repurposed for marine use with dry stacks. Now new trucks are nearly all common rail. Wonder if it makes any difference (NA, turbo, common rail) as too amount of soot at start up. Would think it would be a non issue with common rail.

As best I can tell, with a modern diesel (say 2009 or later), you will less or no flaky soot landing on your boat and your neighbors. We had none of that with out 2012 built Deere engine. But we still had what I'll call haze that built up on surfaces exposed to the exhaust plume. It only impacted out boat, but the stack and all the instruments up there would slowly change from white, to gray, to black. Then I'd clean them, and repeat the process.


I have heard of engines where if you change the thermostat to run the engine a bit hotter, like going from a 170F to a 180F thermostat, it clears up the soot flakes. I think that may have even been a Detroit series 60.
__________________
MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 10-29-2020, 03:04 PM   #47
Guru
 
twistedtree's Avatar
 
City: Walkabout Creek
Join Date: Jan 2013
Posts: 8,242
Quote:
Originally Posted by rslifkin View Post
More modern diesels will soot less. But there will often still be some soot in the exhaust system over time. If the dry stack allows that soot to get wet in the rain, or accumulate in a spot where it can get blown out at the next startup, then you may get soot splattered around at startup. I'd say it depends as much on the exhaust system design as it does on the engine itself.



Good point about rain. Standard operating procedure for a Nordhavn dry stack is to cover it when not in use. A small fender with one end cut off fits perfectly over the exhaust pipe. I had a loop of rope tied to it, and could easily place it and remove it with a boat hook. And a lot of people put a stocking over the stack on startup to catch any soot blast, but I never had to do that.
__________________
MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 10-29-2020, 03:55 PM   #48
Guru
 
firehoser75's Avatar
 
City: Nanaimo
Vessel Name: former owner of "Pilitak"
Vessel Model: Nordic Tug 37
Join Date: Feb 2018
Posts: 1,627
Dan,
Yes, I don't know why the photo "inverted itself", it is fine on my computer. I have had that happen periodically on the forum before. Strange how sometimes but far from always???


I am not a big fan of dry stack. For one example, I had just finished 2 days on my hands and knees cut polishing (washed the boat the afternoon before), then separate polishing, followed by 2 coats of hand applied paste wax on the roof of my pilothouse. The very next day, I was down to the boat, and the roof was covered with black sooty, oily patches that would not wash off! There is a fuel dock about 60 yards across from me, and the marina has many commercial tugs and fish boats, all with dry stacks not that far away. It was a bit upsetting, but I could not pin point anyone in particular, just know it was from a dry stack.
I know, move the boat, but there are only so many places that a person can find moorage.
__________________
Tom
Nanaimo, BC
firehoser75 is offline   Reply With Quote
Old 10-30-2020, 05:59 AM   #49
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 22,553
"Is the keel cooler sufficient to avoid the need for bubblers?"

A bubble system is to keep the marinas pilings from being lifted by the ice with tide changes.

Old wooden boats had ice problems from the cotton in seams freezing and being started by the ice. The ice would melt and the boat could sink , no problem with a modern GRP vessel.

Being frozen in is fine as long as the seacocks are below the thickness of the ice , or secured and winterized ..

In the spring when the ice is melting it is necessary to use a pole to enlarge the ice free hole the boat is floating in to save the water line paint from being scratched.


A bubble system is much un-fun to live with , it sounds like being in a fish tank for a few months.
FF is offline   Reply With Quote
Old 10-30-2020, 07:44 AM   #50
Guru
 
City: Newport, R.I.
Vessel Name: Hippocampus
Vessel Model: Nordic Tug 42
Join Date: Jul 2020
Posts: 2,629
FF in our area bubblers are commonly placed under boats if wet stored over winter. They are the concern not pilings. Being iced in can injure boats. Typical set up is shrink wrap on top and bubblers underneath. Both done even if folks aren’t living aboard. With our tides an ice free ring around boats decreases risk of damage.
Hippocampus is offline   Reply With Quote
Old 10-31-2020, 08:18 AM   #51
Guru
 
City: Melbourne, FL
Join Date: Dec 2014
Posts: 1,729
What about soot on neighboring boats?

Quote:
Originally Posted by rgano View Post
Downside of dry exhaust is the noise and if vented up, the sooty mess which develops over time on topside surfaces.
If you spend any time warming up at the dock with dry stack exhaust, you may not get along with your dock neghbors since it soots up their top decks too. Anyone downwind is at risk of getting soot on their decks while you prepare to go out.

Most commercial boats don't have pretty white non-skid decks and a little soot isn't a big deal, but pleasure boats with non-skid decks are hard to clean the soot out of the non-skid.
stubones99 is offline   Reply With Quote
Old 10-31-2020, 10:25 AM   #52
Guru
 
City: Newport, R.I.
Vessel Name: Hippocampus
Vessel Model: Nordic Tug 42
Join Date: Jul 2020
Posts: 2,629
Interesting I’m getting conflicting information from sources outside this site.
Using keel cooler to prevent ice in makes little sense. On most boats it’s on one side only. So with one side deiced it would either force you into or away from the dock. Either your fenders would pop or your dock lines stretch and break or it would be difficult to get on and off the boat if you were in a slip. If iced in while out it might make some sense but it would be bad for the engine running with no load and would be very expensive. Basically not an option.
If you keep your stack clean and dry soot isn’t much of an issue. Straight vertical runs, high stack, covered when not running, moisture taps drained before start ups, mesh at start up and other measures decrease soot significantly. Owners tell me they haven’t had issues with neighbors if they give it a modicum of attention.
Hippocampus is offline   Reply With Quote
Old 10-31-2020, 11:07 AM   #53
Guru
 
mvweebles's Avatar
 
City: Saint Petersburg
Vessel Name: Weebles
Vessel Model: 1970 Willard 36 Trawler
Join Date: Mar 2019
Posts: 4,629
Hippo - I probably had 30k miles on nordhavns back in the day. I do not recall a sooting issue as described here either. I do recall a couple times with a following wind where there was some mild sooting accumulation, but not often. In all fairness, I made long runs, often over 700 mile straight shots so I didn't start-up often. And did take the precautions you cite.

Given you're looking at a N40 with a smaller 4 cylinder, I don't think you'd see much. Definitely see a little but not a big issue unless engine was not running properly.

Peter
__________________
M/V Weebles
1970 Willard 36 Sedan Trawler
mvweebles is online now   Reply With Quote
Old 10-31-2020, 12:06 PM   #54
Guru
 
C lectric's Avatar
 
City: Gibsons, B.C., Canada
Vessel Name: Island Pride
Vessel Model: Palmer 32'
Join Date: Oct 2007
Posts: 4,033
On my dry stack in rain country I cover the exit with a piece of painted PVC pipe with a handle attached so it is easily reached.

Biggest sooting cause was forgetting the cover and/or running too easily just before docking. Easily correctable.

Yes, I have had sooting before but never anyone else, only us.

THe last big change was when I replaced all the injectors. The engine runs cleaner now, noticeably so.

So clearly it may depend upon exhaust design, the engine, its tune and on the operator.
C lectric is offline   Reply With Quote
Old 10-31-2020, 12:53 PM   #55
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,791
I have bought new injectors too, looks like its a lot more complicated on a Cummins than a Lehman! I also have a plastic drain pipe with a handle for the stack.

I have no salt water in my boat except for the genset. If I get soot on startup, I have a battery-powered leaf blower that takes care of it. No saltwater, no coolers with salt water, no saltwater pumps. Oops. I do have a salt-water fire pump. And it has one of those cheap-ass Jabsco rubber impellers that I hate...

My keel cooler is inside the keel so no worries there. There are better ways.

Besides, nobody would reject a boat simply because of its exhaust, you live with it.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 10-31-2020, 01:20 PM   #56
Guru
 
twistedtree's Avatar
 
City: Walkabout Creek
Join Date: Jan 2013
Posts: 8,242
Quote:
Originally Posted by Hippocampus View Post
Interesting Iím getting conflicting information from sources outside this site.
Using keel cooler to prevent ice in makes little sense. On most boats itís on one side only. So with one side deiced it would either force you into or away from the dock. Either your fenders would pop or your dock lines stretch and break or it would be difficult to get on and off the boat if you were in a slip. If iced in while out it might make some sense but it would be bad for the engine running with no load and would be very expensive. Basically not an option.
If you keep your stack clean and dry soot isnít much of an issue. Straight vertical runs, high stack, covered when not running, moisture taps drained before start ups, mesh at start up and other measures decrease soot significantly. Owners tell me they havenít had issues with neighbors if they give it a modicum of attention.

I don't think a keel cooler would be of any use for ice mitigation, simply because it only gets warm when the engine is running, and the engine won't be running while at dock.


And for a dry stack, there are mitigation measures to control soot. The two most effective appear to be keep it covered when not in use, and run up the engine to WOT for a spell at the end of a cruise.


Honestly, I think the best type of exhaust is the one you have in your boat. Like so many things, there are pros and cons and it's really a toss up in the end. You will learn to appreciate the pros, and find ways to deal with the cons.
__________________
MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 10-31-2020, 09:50 PM   #57
Guru
 
City: Newport, R.I.
Vessel Name: Hippocampus
Vessel Model: Nordic Tug 42
Join Date: Jul 2020
Posts: 2,629
Thanks guys. Further confirmation of what I’m hearing from other sources. What’s the longest interval before shut down that the WOT throttle period makes a difference? How long should you be at WOT for it to make a difference ? I’m assuming that’s done to blow out particulate and other products of incomplete combustion. Is that correct? Given full combustion produces water and CO2 is it to have the whole exhaust run bone dry at shut down? Why does that period of WOT help?
Also been told keel cooler fouling is much more of a problem the less frequently a boat is used and the shorter the period of time the engine is on for those runs. Am I right in assuming that’s because with frequent prolonged use growth dies and with movement falls off?
Hippocampus is offline   Reply With Quote
Old 10-31-2020, 10:39 PM   #58
Guru
 
klee wyck's Avatar
 
City: Seattle, WA USA and San Carlos, Sonora MX
Vessel Name: Domino and Libra
Vessel Model: Malcom Tennant 20M and Noordzee Kotter 52
Join Date: Feb 2014
Posts: 831
Quote:
Originally Posted by Hippocampus View Post
Thanks guys. Further confirmation of what Iím hearing from other sources. Whatís the longest interval before shut down that the WOT throttle period makes a difference? How long should you be at WOT for it to make a difference ? Iím assuming thatís done to blow out particulate and other products of incomplete combustion. Is that correct? Given full combustion produces water and CO2 is it to have the whole exhaust run bone dry at shut down? Why does that period of WOT help?
Also been told keel cooler fouling is much more of a problem the less frequently a boat is used and the shorter the period of time the engine is on for those runs. Am I right in assuming thatís because with frequent prolonged use growth dies and with movement falls off?
I only have the experience of one dry stack and keel cooled boat, so pretty limited. However, no soot problem that I have ever detected. I never run WOT.
No fouling on the cooler which, on this boat, is just a box on the hull that looks like a bilge keel that is full of coolant. See photo. No fouling.
And, regarding water coming into the exhaust path, of course the stack is equipped with a flapper cap with an adjustable counterweight just like all good on land construction equipment that has a vertical stack. Not rocket science.
A bucket over the stack...really?
Attached Thumbnails
Libra cooling fins.jpg  
__________________
Bill
klee wyck is offline   Reply With Quote
Old 11-01-2020, 11:10 PM   #59
Guru
 
C lectric's Avatar
 
City: Gibsons, B.C., Canada
Vessel Name: Island Pride
Vessel Model: Palmer 32'
Join Date: Oct 2007
Posts: 4,033
I disagree with WOT. All you need do, if indeed a harder operation is needed, Is to crank it up higher than you normally operate.
Another 200 to 300 revs for several minutes should take care of it.

I will add that when you start In morning don,t idle your engine for 1/2 hr. Get moving slowly but get a load on it. All should be ready except the line needed to hold in place,
Start ,cast off and go.

Cover the stack when not operating.
C lectric is offline   Reply With Quote
Old 11-01-2020, 11:59 PM   #60
Guru
 
guy with a boat's Avatar
 
City: SoCal and Vancouver Island
Vessel Name: Tortuga
Vessel Model: Nordhavn 63
Join Date: Aug 2016
Posts: 504
My main engine has a dry stack and we have never had a sooting problem. Not any noticeable soot on our boat and no complaints from neighbors. We have a recent (2015) Deere 6090 and I do run it up to 70% power for 15 minutes or so sometime in the last hour of a long run, and those factors may help.

Our wing engine (Deere 4045) is a wet exhaust, so I still get to change an impeller every year or two. Regarding noise, the wing is noticeably louder than the main, despite being half the size. I don’t know if the exhaust systems play a role in that or not.

Lastly, I have never put a bucket or any other cover over the exhaust. I’m not sure how to explain the difference between my experience and those of some others, but we have zero complaints or issues with the dry stack.

I think either system can be equally desirable, and the quality of design and construction of the boat is far more important than the type of exhaust system.
guy with a boat is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 10:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012