Vents and seacocks

[jpwrist]

Two quick questions regarding my 2001 Albin 28

1) Why are the (two on each side) vents on the starboard and port sides facing forward. I understand that they will allow more air in when moving, but it appears that they should also encourage salt water to enter the engine compartment. Should I reverse them and face them backwards?


2) Why are the seacocks in the Albin 28 not screwed in through the hull? They are triangular on the inside and have three screw holes at each of the corners, but it appears that the way they are attached is by the threads that are on both sides of the hull and by 5200 or 4200. I recently removed one of them and don't know if should use the screw holes when I reinstall them.

Thanks in advance for any comments.

Jos

[Pitou]

Jos, ... 1).you're right sea water can and will enter through those vents on a day with serious sea state, but under most conditions will not. Last summer I posted my experience with this when the hose from one of the vents filled with water and restricted air flow because the hose came into the bilge and looped back up createing a trap. The fix ......... take the collective loop out by cutting a short piece out or rearrange.

Here is the thread / there was a good discussion :
viewtopic.php?t=995&highlight=vents

2). I have had to replace one seacock as well and the using the bolt holes are not necessary. The 4200 is fine and is more easily removed. When screwing the two sides together and setting in a bed of 4200 all is good.

[Russell]

I replaced one of my seacocks last year and since the original already had three screws into the hull I just put some of the 4200 on them and put them back in. They are probably not necessary once the 4200 hardens, but in my case it made it easy to screw in the thru-hull part from below without the seacock turning.

[Capt Ron]

I read Pitou's comments on salt build up in the vents when he first posted the issue. This summer I checked my vent tubes and sure enough there where were deposits of salt formed in the lowest portions of the tubes. While there wasn't enough of a formation to cause restricted air flow I still removed it. Well, I guess I'm a follower of the principle of the "IF LIFE GIVES YOU LEMONS, MAKE LEMONAID", I used the salt to preserve the left over bait from the days fishing. It worked like a champ! I like to think the Albin designers had this in mind! Or maybe I'm going a little crazy during the winter layup.

[mhanna]

Jos, I had the same questions.... Im glad you brought them up.

#1)I had to look at pictures of my boat to see that all 4 vents do scoop forward. Hmmm the top ones dont bother me too much but the lower ones are not that far up. On my old boat one side was forward the other side was back forcing air through the eng area. With them all facing forward I am guessing that slight pressure will build up under the engine (via the ducts) and vents out through the other openings under the cowling ? or does the engine itself suck that much air ? I will have to go look now and see if the vents go all the way to the top scoops. There really cannot be much gained by the forward facing vents, they are almost flush. But the downside is it can scoop a good amount of water if it sprays up. I will go take some pics.

#2) It also bothered me that the they put in flanged seacocks but did not screw them down to the hull. I believe the whole reason for a flange, rather than a thruhull thread is that if we strike something hard underwater and it sheers off the outside flange the valve and flange stay on the hull and it continues to operate normally (until you get home and fix it). I dont know how strong the 4200 is, but if you hit something hard enough to rip off a flange...well... you get the idea

I was just looking in a catalog and they make a flange with just a thread, this would let someone very easily change the valve if need be. I hope I dont need to do it though.

Matt

[Mariner]

1. Yeah, engine room vents on the outside of the hull have never made sense to me. Ours are inside the gunnel. I wouldn't want them any other way.

Yes, the engine can suck up that much air when underway, but usually it doesn't. That's why one vent usually faces forward, and another faces aft. Sometimes there will be two facing forward and two additional facing aft. Look around, you'll be surprised what you find.

2. Bolt-flanged seacocks are usually intended for wooden-hulled boats. You can't safely screw into a fiberglass hull without risking damage. Most seacocks have the screw holes on them just to make them universal.

[Veebyes2]

Vents on the outside can be dangerous. I saw an A36 fast trawler at a boatyard in the fall of 99 at Tilghman Island, MD. Apparently she was crossing the Chesapeake Bay in a beam sea. She was rolling heavily 'sipping' water into the intake with every roll. The bilge pumps failed. Somehow by the time the crew realized what was going on it was too late. They got her to a mudbank where she flooded.

A sorry sight when I saw her. Cabin paneling delamenating. Upholstery a mess. Don't know whatever became of the boat. It was a great project for somebody with a bit of know how & lots of time.

[jpwrist]

Thanks for all the helpful comments.

With respect to the vents, if I face the upper ones on the starboard and port sides facing forward and the lower ones facing aft, will I get enough air into the engine compartment, or should I add another vent, for instance, in the engine box to make sure I get enough air to the engine? I am basing this on the assumption that needs to supply enough air to both feed the engine's air needs and provide for some surface cooling.

By the way, I noticed from the earlier conversation thread noted by KevinS that someone said one should not vent directly to the engine air intake.

Jos