replacing solar vents

[anon]

Hello. I am a very new C34 owner and also new to sailing. I wish to replace the nicro solar vents and bought replacement 3" units. The actual hole in the deck is 4.5" and there were spacers in the original openings. I have been unable to find new spacers on line. The nicro literature says that the fan body should be a close fit in the opening. One option might be to go larger and get the 4" nicro fans but they require 4.75" diameter openings. But then how would I make a good 4.75" diameter opening?
Finally, which particular compound would be best for sealing the fans?
All advice greatly appreciated.
Thank you in advance.

[mregan]

I replaced one of mine with the 4".  Used a jig saw to open the hole a bit to fit the new vent.  I bedded the vent with butyl gasket material. 

[DaveBMusik]

My 4" vents fit fine after removing all of the old plastic sleeve

[anon]

Thank you so much. I will buy the 4" versions now. I guess I can use the 3" in hatches at some stage?
Is there a trade name for the butyl gasket material?
Thanks again.

[Dave Spencer]

Welcome aboard Sophie,
Butyl can be bought from Mainesail, one of the technical gurus on this and many others forums.  I'm in Canada and I got my 50 ft roll that has lasted me years from HMP Marine in Toronto.  I think it is also available at building supply stores.  Ask at the window glazing department.  There is no "brand name" that I'm aware of.

[rmbrown]

Highjacking a bit, but it seems related...

My boat has one solar vent over aft cabin and two cowl vents forward of the dodger.  The cowls aren't in dorade boxes so they scoop up rain as well as air so I don't feel like I can leave them in the boat.

Keep in mind my boat is new to me so I've yet to get a night board, much less a summer night.

Are solar vents intended mostly to move a little air when the boat is closed up?  Or are they intended to make the boat more livable when you are own board but maybe it's raining too much to put up a wind scoop and really open things up?

Am I better off building dorade boxes for my cowls, replacing them with solar vents, or is there something else I'm missing?

[Stu Jackson]

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Am I better off building dorade boxes for my cowls, replacing them with solar vents, or is there something else I'm missing?

Recognizing the lack of real dorade boxes on the cowls, I simply never face either one forward.  Even  at anchor the boat swings enough so with them turned sideways we get some ventilation.  When I lived in SF I had them face out, since the prevailing summer breeze in my slip was from starboard.  Here in my new digs, I turn them both aft 'cuz the bad weather comes from dead ahead.

I'd think a lot more about them before you remove them, 'cuz folks who have had both Mark I and Mark II boats (and there are quite a few) bemoan the lack of the cowls.

[rmbrown]

Definitely worth living with the boat for a season before making any changes that I can make in the water.  I've made plenty while in the yard.  With any luck, she'll get wet again wednesday.

[Noah]

You might think about replacing your Cowl/dorade vents with these Air-Only" brand vents. I did so on my boat and they do keep the water out.

http://www.air-onlyventilators.com/


Here is a link to some discussion.
http://c34.org/bbs/index.php/topic,6238.msg40976.html#msg40976

[DaveBMusik]

My cowl vents had mushroom vents inside which serve a similar purpose as true dorade boxes. They can be screwed closed in heavy weather. I purchased replacements through Hamilton Marine.

[Stu Jackson]

The ones I bought to replace my OEM ones have a quick release "trigger" to close them.  I just leave them open.

Tech Notes  August 2005

[anon]

My dorade vents are in poor condition. The boat is an 87MY. What options are there for replacing them apart from the interesting "air only" vents.
Thank you.

[Ron Hill]

Sophie : The 1986/1987/1988 C34s have Vetus 4" dorade vents.  Then in 1989 and subsequent C34 the factory installed Nicro 3" dorade vents!!

Always identify your C34s production year when making a post.  That way we can give you a correct answer.

A few thoughts

[Stu Jackson]

Here are the OEM Vetus vents.

[mtmaksim]

...in true Catalina fashion, I think they would use whatever they had available!
I went off the approach that an 89 should have 3" vents, and purchased the new 3" dorades to replace on the boat this spring. When I went to install them, it turns out they had 4" vents originally!