Ventilation aboard Legend 40.5 1997

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Luman

.
Oct 2, 2009
40
Hunter Legend 40.5 St Paul
No problem. Here is a PDF of a manual which contains their recommendations. http://www.marinco.com/files/support/product/manuals/minivent manual.pdf note exhaust is preferred IF there is vents in. IMHO, the stern vents qualify, thus the exhaust. BTW, the model available here has a positive closure so no concern if things get nasty. I have only closed it once. One more thing: do not even attempt this without a hole saw. You can get cheapies at Harbor Freight. Having said all that and that ventilation is good, I'm betting your smell is the holding tank. :cry:
Got one!
I will install it on the fwd cabin hatch. That should help a lot. Yes, the more I'm looking at it and the more I am tempted to believe it is related to the holding tank and/or it's plumbing. I will work on that soon.

Many thanks:dance:
 

Polson

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Oct 16, 2009
2
Hunter 42' Passage Blaine Washington
Fresh air/Smelly boat

We had a Hunter 33' now sold and moved to a 42 P.
I had a similar situation - damp and a sulfur smell. I first installed two vents in the hatch boards going into the boat. worked great as long as you have dodger.
This helped the boat breath while away. The sulfur smell after much trial was figured out. The water in the bilge was going black and smelly. Two things. The ground wire connected to the keel was corroded just a bit. I cleaned that up and reconnected. The water stayed clean after that. you must always clean the bilge if shower water gets in. Shower water can get nasty if left for any length of time.

Paul
 

Luman

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Oct 2, 2009
40
Hunter Legend 40.5 St Paul
Re: Fresh air/Smelly boat

Thanks for your input.

YEP, your right. Although it doesn't apply to me as we are not using the lavs for showering,... we use the transom one outside. I try to keep the bilge as dry as possible and I have been successfull at it so far. What I didn't realize though, is that water partly collects elsewhere enroute to the bilge. exemple: fridge drain, condensation, holding tank and plumbing leaks!?! I have to look those ways. I also didn't clean the bilge since and it is black as well. I will clean thoroughly.

thanks Paul
 

Arwen

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Oct 2, 2008
11
Hunter 40.5 Miami Beach
I have my vent set to exhaust also. My logic is, the interior gets warm just by sitting in the water and natural sun hitting it, heat rises, the hatches are in the ceiling, so the heat should be venting out anyway.
I think trying to put those little fans in the position of having positive pressure intake against the rising hot air might be a futile battle. So, go with the flow!

Roger
 
Jun 1, 2009
1,838
Hunter 49 toronto
How to fix the odors

On the 40.5 you need t do the following, or you will always be chasing odors

Firstly, replace your aluminum tank with plastic. Replace all the head hoses at the same time. The aft hose is easy, and the foreward is not. You need to remove all the fwd. cabin bunk cabinetry, and use the old hose as a fish for the new one. Take your time on this.
You also want to replace the deck pump out hose, and get rid of the mascerator unless you use it. If not, it will always have a smell to it.
Next, the fridge and freezer drain directly to the bilge. Even a thimble full of milk will cause the boat to stink from this.
You need to install a sump box which pumps out tho the kitchen sink drain. You will have zero smell in the bilge from that point forward.
Next, install bilge blowers in line with the passive vents on the stern. Have them blow air inwards. Install screens in the hose to keep bugs out.
Use a 12 volt light dimmer as a speed control for the fans. Just have them on the lowest speed possible when you're not on board, and it will continually flush air through the boat. No need for any other venting.
Take up all the floor boards, and clean all the mildew from their underside. Then reseal with varnish.
Hope this helps

Hello,

I am concerned about the fact that there is no constant positive ventilation inside this ship. Although there is tons of openings to vent when aboard, there is nothing when we're away. The reason I'm asking, is that the odor that strucks me every time I get inside realy discuss me. Even things that we bring back home smells for many days.

This is my first boat, so I can't compare with anything else and I didn't get any complaint of any guess yet. I just don't know what to think of this. I understand that, being over water, it is though to keep moisture to a low level but I have installed a humidity tester aboard and I barely see it under 60 % with all hatches/windows closed. Is this normal? Should I consider installing permanent vents, or it's useless?

On the 40.5 you need t do the following, or you will always be chasing odors

Firstly, replace your aluminum tank with plastic. Replace all the head hoses at the same time. The aft hose is easy, and the foreward is not. You need to remove all the fwd. cabin bunk cabinetry, and use the old hose as a fish for the new one. Take your time on this.
You also want to replace the deck pump out hose, and get rid of the mascerator unless you use it. If not, it will always have a smell to it.
Next, the fridge and freezer drain directly to the bilge. Even a thimble full of milk will cause the boat to stink from this.
You need to install a sump box which pumps out tho the kitchen sink drain. You will have zero smell in the bilge from that point forward.
Next, install bilge blowers in line with the passive vents on the stern. Have them blow air inwards. Install screens in the hose to keep bugs out.
Use a 12 volt light dimmer as a speed control for the fans. Just have them on the lowest speed possible when you're not on board, and it will continually flush air through the boat. No need for any other venting.
Take up all the floor boards, and clean all the mildew from their underside. Then reseal with varnish.
Hope this helps.

Thanks
 

Rick D

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Jun 14, 2008
7,186
Hunter Legend 40.5 Shoreline Marina Long Beach CA
That's exactly what they did on mine when it was recommissioned, if I understand you correctly. The hatch plexiglass is probably shot and I think you will find the crazing internally. Having said that, it won't cost anything but time to try.
 

Luman

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Oct 2, 2009
40
Hunter Legend 40.5 St Paul
Hi everyone,

here's an update on my findings. On the ventilation side, I brought my forward cabin hatch glass home (it was leaking anyway) and I bought a Nicro fan. I will try to sand the glass first with 400 grit followed by a 2000 one and compound before installing the fan. The glass has a poor outside surface finish right now. It seems it has been damaged by acid or other tough stuff. It's kind of frosted. Do I have any chance to bring it back to a good appearance? Otherwise I will go directly with a new glass. I, too, thought of putting bilge fans inline with the stern vents. I will install them as intakes and the Nicro will exhaust.

On the odors side, I got to remove the macerator as it was disconnected on my surveyor demand on the purchase as my goal was to sail on the Lake Champlain which prohibits the use of dumping. The macerator and it's plumbing were not very clean and there was still some liquid in the hose that goes to the thru hull valve. That last hose was diconnected from the thru hull but was not capped. I have tried to remove it but it seems to be stuck underneath the lav cabinet. I would like to discard it along with all other hoses since they seem to be due. By removing the other hose (from the macerator to the tank) I found a Y PCV fitting that was barely glued to the top pumpout hose fitting. I was able to break free the two parts by hand. I then removed the tank and discarded the hoses from the tank to the Y and the one from the Y to the macerator. Now I must figure out how to remove the one from the Y to the pumpout fitting on the deck. I'm also wondering if it could be a good idea to replace all those flexible hoses with rigid ABS house plumbing and fittings. They will last much longer than PCV and are odorless,...no? The tank seems o.k. I thought of pressure test it but I'm not sure anymore. Might just change it for a plastic one and sleep better.

After I removed the tank, I found the bottom of the tank compartment in a very nasty condition. There was almost everything that was used to build the boat there. Electrical wires, wood dust in abondance, pieces of laminates, screws, ect. The hole that drains the compartement was plugged with wood dust to about 90% of it's surface. So it is very possible that the tank was leaking, even if nothing got to the bilge.
 
Aug 6, 2009
59
Hunter 40.5 Mazatlan, Sinaloa, Mexico
Another great help when leaving the boat for any length of time, flush some fresh water down the heads. Salt water left standing will stink in short order. Newer vac heads with fresh water flush are for a reason - and eliminate the smell. Many people have gone looking for problems when all it was is dead sea water standing in heads.
 
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