Bilge Vents

gettaway · Post by **gettaway** » Tue Mar 30, 2010 12:25 pm

I am curious if there is a problem reversing the direction of the aft vents on a 77 F-32. The foward facing vent louvers seem like they would scoop in water in heavy seas. While I understand that one would want to diect cool fresh air into the engine room / aft lazarette, it seems that is invites water as well,

Thoughts?

MTP · Post by **MTP** » Tue Mar 30, 2010 12:31 pm

I wouldn't worry about it if you are taking water that high you have bigger issues

g36 · Post by **g36** » Tue Mar 30, 2010 1:31 pm

heres what i did may be right or wrong.i have a 78 f32 and when i purchased mine all the vents were facing forward which i knew was not right. after looking at several photos of f32 i turned my forward vents facing aft . left the aft ones facing forward. i saw several like that so i went with it.
if you look at MTP'S photo you will see his forward vents are on the side of the salon above the hull joint where ours are down on the hull.
there is an arrticle somene probably has the link to a sinking of a f32 in the great lakes i think that had the vents low and i belive this is why later they were moved to the location on the side of the salon.

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captainmaniac · Post by **captainmaniac** » Tue Mar 30, 2010 1:46 pm

You want one set facing forward, the other facing aft, to properly vent the bilge while under way. Any water intrusion should be minimal for either... if it is anything more than spray, you have a major trim problem are out in stuff you shouldnt be !

gettaway · Post by **gettaway** » Tue Mar 30, 2010 2:03 pm

I have read the article on the boat that sank in the great lakes, and the suspected culprit was the vent cowlings. While most of us never intend to get underway in bad weather, it happens, and if the seas are high, or on the beam, taking on water through a vent will only compound the problems one would be facing at the time. Each gulp of water, the lower the vent gets to the waterline, hence my question, does anyone know af any known problems if the vents are turned to face aft?

I am in San Diego, to make it to Catalina or Mexico, its about a 70 mile open water run in either direction. I have done this many times on my 34' trawler, at 7 knots, and have come into some pretty nasty head seas, wind and a very stubborn short swell. I have had saltcicles hanging from the bridge cowling (really) from the salt spray in those head seas...
I am not scared, but I am careful!

g36 · Post by **g36** » Tue Mar 30, 2010 2:29 pm

sorry couldnt resist
i thought my answer was answering your question and also the post by captainmaniac said the same thing.
to properly vent the engine room you need one set facing forward and one facing back. doesnt even matter which are doing what.but if all are facing aft they will cause a vaccuum . all facing forward wont flow air through either. however the forward facing set forces air in and the aft facing pulls air out. i dont think you will blow up and probably wont even be something you can tell but all facing forward or all facing aft is not going to promote air flow through the area. afterall thats the reason they are on the boat. guess you do what you want

gettaway · Post by **gettaway** » Tue Mar 30, 2010 2:32 pm

thanks for the information

ready123 · Post by **ready123** » Tue Mar 30, 2010 2:43 pm

gettaway wrote:Each gulp of water, the lower the vent gets to the waterline, hence my question, does anyone know af any known problems if the vents are turned to face aft?

Mine is setup so the forward vents allow for the blowers to suck air from outside and deliver into the bilge... the aft forward facing vents provide air into the bilge while underway.
If you change yours to the opposite I think the midship vents would then be required to supply air to the bilge while underway... if you look at their setup you will see there is not really any free space to flow air without it going thru' the blower hoses and stationary blower blades... so I would suggest you would need to modify the plenum boxes or move the blower supply away from the forward vents.

Do your aft vents not have a baffle to protect against water ingress.... there is a plate behind my fins at the bottom of the vent.... if you are worried about water getting in over this then as has been said that would be the least of your problems..... you do have an aft bilge pump to deal with this don't you?

From where I sit I think you are worrying unnecessarily....

gettaway · Post by **gettaway** » Tue Mar 30, 2010 2:48 pm

Thanks for the input, and as far as your questions, once the boat is in my slip, Ill let you know. lets just say that I am not worrying but in photographic observation, the vents facing forward look like a water scoop!

Paul · Post by **Paul** » Tue Mar 30, 2010 3:02 pm

I'm not sure how the rear facing front vents are ducted in the F-32 & 36 but in my 26 there are vent hoses that lead down the bottom of the bildge. This way these vents draw air from the lowest point at the front of the engine bay. The forward facing rear vents force air thru boxes at a higher point at the back of the engine bay. This combination creats a circuit that constantly changes the air in the engine bay while under way.

As for water intrusion thru the rear vents, I have 2 pumps in the rear to deal with that. I cant say however that I've been in nasty enough water as to flood my vents enough to kick the pumps on.

Rich Schwochow · Post by **Rich Schwochow** » Tue Mar 30, 2010 9:20 pm

My 78 has a baffel in each rear forward facing vent. In fact once I discovered the port baffe was gone os I made one for it. Years later I found the original in the bilge.

prowlersfish · Post by **prowlersfish** » Tue Mar 30, 2010 9:30 pm

Front vents face rearward rear face forward , thats the way Trojan made them , there was a recall but not sure what the fix was . ( could have been the baffles ? )

TADTOOMUCH · Post by **TADTOOMUCH** » Wed Mar 31, 2010 11:17 am

Here is the link to the article about the SeaMar II which is a F-32 that sank in Lake Michigan supposedly near South Haven, MI

http://www.michiganshipwrecks.org/seamar.htm

larryeddington · Post by **larryeddington** » Wed Mar 31, 2010 4:44 pm

I looked at my F28 and the vents are the original. It has four on each side. the first one faces forward, second one aft, third one forward and forth one aft.

I am installing stainless ones as the originals are made out of plastic that has been damaged in rough dock handling I guess.

ready123 · Post by **ready123** » Wed Mar 31, 2010 4:58 pm

TADTOOMUCH wrote:Here is the link to the article about the SeaMar II which is a F-32 that sank in Lake Michigan supposedly near South Haven, MI
http://www.michiganshipwrecks.org/seamar.htm

Why anyone would use a boat with only one forward bilge pump is beyond me!
I hope any other Trojan owner that lacks an aft bilge pump will make the effort to put one in.

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