Ventilation

[foursailing]

I noticed on my new (to me) 1999 MKII that there really is no ventilation once the boat is closed up.  My old Pearon had a dorade vent in the head that did a really nice job.  I believe the MKI's have 2 dorade vents which now have been replaced with 2 small lewmar hatch's. 

Ventilation is especially important now since I have a bit of a head hose smell issue that I'm dealing with (already ripped out the offending hoses and holding tank - but that's another story)

Any suggestions on adding some additional ventilation would be greatly appreciated!

Bill

[dprice]

I had the same concern and issue. I hated to come on board to a smelly boat.

So I installed a 4" Nicro Day/Night Solar Vent between the hatch and the mast.  I was a little scary to drill a 4" hole in the boat but it was worth it.

It runs constantly to keep air circulating.

I also keep the small top hatchs open in the head and back cabin open all season.  They are under the dodger so no rain gets in.

[Mike and Joanne Stimmler]

You can also unstall those Nicro Solar vents in the hatches if you don't want to cut a hole in your cabin top. i resolved my holding tank smell problem by flushing it out 2 or 3 times with FRESH water then using an enzime product in the tank. Hope this helps.

Mike         

[Jack Hutteball]

Bill,
I have your same setup in our 2001 MKll.  I keep the hatches in the head and aft cabin open to the first notch for ventilation when not on the boat and I have never had a problem.  I do have a dodger above them that keeps any stray water from entering.  We keep our boat in the water all year and run two dehumidifiers during the winter, one in the forward cabin and one in the aft, and keep all cabinets and doors open so the air can circulate freely throughout the entire boat.  As for the holding tank smell, we always flush the system with fresh water after the tank is pumped and we don't have an oder problem.  We have found the biggest source of odor is from the salt water sitting in the lines/tank.
jack

[foursailing]

Thank for the advice!  The vent Nirco Solar vent sounds like a good idea.  I was also thinking of installing a teak louvered vent in the middle companionway board.

Appreciate your help!

Bill

[Stu Jackson]

A search on "dorade" if you haven't done one yet also provides many ideas.  Good luck.

[Ron Hill]

Bill : If you have the dodger up as I do - let the head hatch open about an inch or two with the screen in. 
As you mentioned, a louvered vent in the center hatch board will also help.   

[David Arnold]

I have a 2005 MKII and plan to install a 3" solar vent in the main cabin hatch as previously suggested but I always leave all 4 hatches open to the first lock point.  I have never had an odor problem and incoming rain water is not a problem as the hatches have enough of an overhang as to provent water from entering.  As far as odor from the head is concerned, I flush the tank once or twice with fresh water after each pump out and when leaving the boat for the week I always pump about a quart of fresh water with just a bit of bleach through the system from a "Y" valve I have in the intake line.  Hope this helps.

[Mike and Joanne Stimmler]

David, I don't quite understand exactly where your Y valve is connected but I hope you don't have a dirrect connection from your fresh water system to your holding tank, If so you could be open to bacterial contamination. Hope my concerns are un-warranted.

Mike

[David Arnold]

Thanks Mike,
Your concern is appreciated and it was in fact this forum that prevented me from hooking up the head to the fresh water system.  I did however install a "Y" valve just above the through hull with a hose long enough to run up to the sink.  When I leave the boat for the week I simply run some water in the sink (with stopper in place) with a splash of bleach, by-pass the through hull and "pull" some fresh water through the head system.  Come Friday night when we return the boat smells as fresh as can be.  This system makes is very easy to winterize in the fall as well; empty the holding tank then just bypass the through hull and pump in anti-freeze and the head system is good till spring 

[Ron Hill]

As I've mentioned before, I installed a 4" solar vent between the mast and the Vberth hatch.  Did that back in 1989 and it's worked great all of this time.  Keeps the air moving!!