Cabin Ventilation

[reedtg3]

I took Capt_Nemo's advice and put a hurricane tie over the sail cover.  We didn't have much wind up here, but I did take on about a cup of water in what would be the battery locker (if I had a battery up there).  Cattail's Purser has authorized the purchase of a cabin ventilation system to prevent mildew.  I need advice.  Should I install a passive vent ($) on the forward hatch cover or really release austerity countermeasures by installing a solar & rechargeable NiMH battery powered vent ($$$) through the deck on the flat area just behind the forward hatch?  Anybody have any experience with this issue? Will a passive vent provide sufficient ventilation when the hatches are all closed or do I need a fan to push the air out?
TReed, CP 17 SC 377 Cattail, Lake Harris, FL       

[Craig]

You probably are getting some seepage around the mast. A simple if not elegant solution is to use some flexible "rope caulk" available at Ace hardware to seal the mast/deck juncture. I had the same problem with "Cattitude". The problem with regular caulk seems to be that the constant "working" of the mast causes the caulk joint to fail. The rope caulk stays flexible an can be worked into a nice fillet around the mast and re-worked easily if leaks return.

[capt_nemo]

TReed,

I haven't had any ventilation problems because I store my boat with a full white polytarp cover as shown here:



The cover is open at both ends to permit air flow. And, on the boat I close the sliding hatch but leave the hatch boards out allowing air to circulate. Also open the forward hatch a crack. It seems to work in the humid SW Florida air.

I realize that if boat security is an issue you must close all hatches and ports, and lock the hatchboards in place. In that case, whether you opt for the passive or battery operated vent, I would suggest creating another protected opening to permit a good volume of AIR FLOW. Whether the air flows into or out of (fan) the vent you choose it must be able to flow out of or into the boat from another opening. On larger vessels this is accomplished with passive Dorade Vents fore and aft which you might also want to consider. Otherwise, to complement your forward vent (whatever it is) consider adding one or more vents with appropriate covers either in the hatch boards or somewhere aft like in the vertical surface between the cockpit seat and cockpit sole (floor). Although tempting, because of its overhead protection, stay away from the fuel storage compartment - don't want gas fumes going down below.

With all that said, if you haven't had a mildew or ventilation problem, before cutting up anything on the boat you might want to try using some of the STAR BRITE No Damp Dehumidifier crystals or No Damp Ultra Dome pellets which are inexpensive and available thru West Marine as well as other chandlerys. I personally would try these first as a preventive measure. Then, if need be, I would choose a battery powered vent to assure good AIR FLOW with the additional vent(s) as mentioned above. If possible, the battery powered vent would be located on the forward hatch, NOT IN A HOLE THROUGH THE CABIN TOP!

Hope this provides food for thought.

capt_nemo

[Billy]

For GOOD airflow, you need a place for the air to go in and a different place for the air to out.

I have a round solar vent in the middle of the hatch installed by a P.O.  It doesn't really work too well. And now I have a hole in my hatch.

[brackish]

My boat (23) came to me with one of those cowl vents on the foredeck that consists of a rubber cowl and a plastic base.  Five years old when i got it, the rubber cowl was split and the plastic base was crumbling.  Since the hole was there, I replaced it with a solar only (no battery) nicro fan exhaust vent. Got the stainless steel cover to protect it.  Three years later, it is still going strong, checked it yesterday.  You do need a supply opening for an exhaust vent to work properly, but on my 23 there is plenty of area between the top of the hatch drop board and the sliding hatch cover. 

Boat stays in the water year round and I've never had a spot of mildew.  I have shore power and during the winter, I do put a small heater set to come on only at freezing.

[Tom Ray]

You probably are getting some seepage around the mast. A simple if not elegant solution is to use some flexible "rope caulk" available at Ace hardware to seal the mast/deck juncture. I had the same problem with "Cattitude". The problem with regular caulk seems to be that the constant "working" of the mast causes the caulk joint to fail. The rope caulk stays flexible an can be worked into a nice fillet around the mast and re-worked easily if leaks return.

At the risk of stating the obvious, it is also possible that he got water in the battery area because the mast was folded, leaving a mast-sized hole in the top of the boat. Leave the mast up or plug that hole.

As to solar/passive vs fan-powered ventilators, I have used both. As you would expect, the fan moves a whole lot more air, but the passive ones do keep some air moving. In a small cabin like ours, I'd think passive would be OK if you want to put a vent.

[reedtg3]

Update:  I found the leak.  The mast was up, but the sail track was inadequately (I could see light looking up from below) caulked.  Problem solved.  Now, I just wanted to give you boys (and girls) an opportunity to talk me out of, or talk me through, drilling a hole in the lexan forward hatch to install a passive vent.  I understand that I should attach clear contact paper on both sides of the hatch and then use a hole saw attached to a variable speed drill on slow with very little pressure to cut partially through the lexan on one side and then repeat the process on the other side.  Sounds simple, right?  What am I missing?  Maybe I should call Hutchins to price a replacement hatch before I start?  Mr. Gridley here, awaiting instruction.
TReed, CP 17 SC 377 Cattail, Lake Harris, FL

[cavie]

You don't need any instructions. Sounds like you've done it before.

[reedtg3]

Now hear this:  The lens inside the Sun Cat forward hatch is made of tempered glass, not polycarbonate or plexiglass.  And, because the frame is molded around the lens, replacing the lens with plexiglass doesn't appear to be an option.  At this point, however, I may just have to "pee on the fence" before I believe it.  Removing the shards of glass from the frame shouldn't be too difficult.  It's a good thing I attached contact paper before I started drilling.  I'll let you know how it works out.  Hey, messin' about in boats is messin' about in boats.   
Tom Reed, CP 17 SC 377, Cattail, Lake Harris, FL   

[capt_nemo]

Sounds like you are having tons of fun. Please save some for the rest of us!

Good luck, and keep us posted.

capt_nemo

[bfelton]

I have a 2000 sun cat.  The glass or whatever it is on my boat is totally separate from the frame. 

Bert