Lazarette Engine Hoses - How Should They Run? (+Photos)

[avd155]

For my design, I'm attempting to make as many water-tight areas as possible. This means that the lazarette locker needs some consideration, because there are at least 4 hoses that need to go through the lazarette bulkhead. Those are:

* Air vents from engine compartment - 2 holes, each 4" in diameter (or so)
* Engine exhaust hose - 1 Hole, 2" in diameter (or so)
* Bilge hose - 1 Hole, 2" in diameter (or so)

I have a couple of questions (which I will list below), but first off, let me share a few photos of how how my lazarette locker currently looks as well as a description of my current plan how to make it all work:


Caption: Notice that currently, the bulkhead is totally tabbed in, no way for water to move forward to the bilge (until I add a drain with a valve with a hose straight to the bilge)


Caption: Here you can see the future engine compartment vent, as well as one of the future thru-hulls exhaust/bilge pump.


Caption: This image shows the area below my cockpit where the hoses may run. I beefed up the lazarette bulkhead and it's totally water-tight.

Original Hose Set-up and My Original Plan:

Originally, the hoses ran directly below the cockpit sole and through the lazarette bulkhead at it's lowest point in the locker, but this meant that they created gaping holes where any water could flow (uncontrolled) and splash down into the bilge. I had planned to build a kind of "box" that would still allow the hoses to come through the lazarette at this low point. The box would form a kind of "wall" preventing water from running through these 4, 2" - 4" diameter holes, but would take up a lot of lazarette space. (Note: You can see the grinding prep I did for this in the first image above to get an idea for the basic size of that box)

My Current Plan:

My current idea is to have all the exhaust go through the lazarette bulkhead as high as possible in order to keep any holes in the lazarette bulkhead as far above the waterline as possible. The idea is that the entire lazarette could be filled with water, and no water would flow uncontrolled into the bilge. If I build it high, the 4" and 2" holes will be far above the waterline, but this poses a couple of questions.

Questions:

1) What is the most extreme angle that the engine exhaust hose can bend? For my purposes, if I can bend the engine exhaust nearly 90 degrees to allow it to run along the cockpit bulkhead, then up to the underside of the deck, (inside the sea lockers) the hose will exit the sea lockers, into the lazarette a high enough angle to make me feel the lazarette is water-tight enough.

2) How should the vents for the engine air intake/outake be angled? This is a similar question to the exhaust question above, but since I'm moving air (instead of liquid exhaust like question #1) I am wondering how these hoses should be sloped from the engine compartment to the air vents in the lazarette area to create the perfect air flow.

Wrap up

Hopefully someone is following along at this point, I've been resisting posting the quesiton, because it's a little complicated since I'm searching for the most "water-tight" lockers as possible while also having nice clean hoses.

If anyone has images of the inside of their sea lockers/below the cockpit showing how all their hoses/air tubes run, feel free to share. It might trigger some ideas for me. Thank you in advance for all your valuable input (no matter how small!) Oh, and here are a couple more images of the area in question that may (or may not!) be helpful:


Caption: Here you can see the cockpit bulkhead. You can just see below the bulkhead the future engine compartment area.

http://www.flickr.com/photos/50069396@N ... otostream/ (sorry, this one isn't embedding properly, because of it's orientation)
Caption: This image is probably the most confusing, but seen with the other images it might not be so much. Basically, this image is looking UP along the cockpit bulkhead, through the starboard sea locker and shows the area along the deck (inside the sea locker) where I could easily run tubing that would be totally out of the way of below the cockpit sole.

[tpl]

> bristol 27

nice boat. One of your photos shows 2 cockpit lockers:
Do they drain into the bilge?

> watertight lazarette

if you're really serious, the obvious thing to do after
sealing the plywood bulkhead completely, especially at
the bottom--and reinforcing it to withstand all that
water, your effort with the hoses being pointless if
the bulkhead gives 'way--after all that, you install suitable
flanges back-to-back, so for example your exhaust has a
2" flange on the interior side of the bulkhead, and
another such flange on the lazarette side: then you use
2 hoses, suitably doubled hoseclamps: look Ma, no
holes:-)

my boat is similar to yours, with above-water counter,
dogable lazarette hatch, and the bulkhead. By no means
is it water sealed at the bottom; I run the exhaust and
bilge hoses through close-fitting holes at the top, and
the only problem I have in heavy weather is water
backing up into the diesel:-(when I forget to shutoff).

[avd155]

One of your photos shows 2 cockpit lockers: Do they drain into the bilge?

Obviously they aren't built yet, but my design will call for these to drain to the bilge via a valve and tube set-up, similar to the one I described for the lazarette locker. These will be able to be closed or opened, but unfortunately, due to the need to access the rudder and stuffing box, I won't be able to make these as water tight as I would like.

if you're really serious, the obvious thing to do after sealing the plywood bulkhead completely, especially at the bottom--and reinforcing it to withstand all that water, your effort with the hoses being pointless if the bulkhead gives 'way--after all that, you install suitable flanges back-to-back, so for example your exhaust has a 2" flange on the interior side of the bulkhead, and
another such flange on the lazarette side: then you use 2 hoses, suitably doubled hoseclamps: look Ma, no holes:-)

This is an interesting idea, do you happen to have any examples of what these hose flanges look like? And yes, I am serious about making it water-tight :). I even made the entire area under the v-berth water tight which is nearly 1/2 of the boat. The tops of the lockers are at least 4 inches above the waterline and are quite voluminous, but that's for a blog post or forum post in the future.

[Triton106]

Andrew,

Great restoration job. I am working on similar ideas for my Triton down the road so I will be very interested in your project.

I am not following the reasons you chose to lead the 4 inch wide ventilation hose all the way to the lazarette. I also don't understand why you need one intake and one exhaust. I have an Atomic 4 and I only have one hose for engine room ventilation. Any reason why you don't have the vent hose exit in cockpit well?

1) What is the most extreme angle that the engine exhaust hose can bend? For my purposes, if I can bend the engine exhaust nearly 90 degrees to allow it to run along the cockpit bulkhead, then up to the underside of the deck, (inside the sea lockers) the hose will exit the sea lockers, into the lazarette a high enough angle to make me feel the lazarette is water-tight enough.

My wet exhaust also exit through the counter transom through an inverted L shaped bronze pipe. The pipe bends 90 degrees at the top. This design prevents any following sea from entering into the exhause hose. Ideally there should be a valve where the wet exhaust hose is connected to the bronze pipe. This is something I will do down the road.

if you're really serious, the obvious thing to do after sealing the plywood bulkhead completely, especially at the bottom--and reinforcing it to withstand all that water, your effort with the hoses being pointless if the bulkhead gives 'way--after all that, you install suitable flanges back-to-back, so for example your exhaust has a 2" flange on the interior side of the bulkhead, and
another such flange on the lazarette side: then you use 2 hoses, suitably doubled hoseclamps: look Ma, no holes:-)

This is an interesting idea, do you happen to have any examples of what these hose flanges look like? And yes, I am serious about making it water-tight :). I even made the entire area under the v-berth water tight which is nearly 1/2 of the boat. The tops of the lockers are at least 4 inches above the waterline and are quite voluminous, but that's for a blog post or forum post in the future.

I don't think back-to-back flange will work well for bilge and wet exhaust as the bulkhead will certainly be water damaged. However, a double sided thru hull like these will work very nicely.



Good luck with your project. Please post pictures of your final design.

[avd155]

I am not following the reasons you chose to lead the 4 inch wide ventilation hose all the way to the lazarette. I also don't understand why you need one intake and one exhaust. I have an Atomic 4 and I only have one hose for engine room ventilation. Any reason why you don't have the vent hose exit in cockpit well?

I also had an Atomic 4, and it had 2 engine air scoops in the lazarette. Presumably, one faced forward, one faced backwards, so passive airflow would bring cool air in and exhaust hot air. I believe these vents must be in the lazarette (not in the cockpit) since they are fairly large and will need cowls to protect any water from going inside. To be honest, I don't have much experience how well these work nor how necessary they are. Am I wrong to assume these are not required?

Please post pictures of your final design.

Certainly, I will have a full illustrated digital drawing of my final design, but I'm learning that things are change often enough, that once I finish a drawing of one design, the next week I have the design tweaked slightly again. For now, I'm going to try to finish my basic construction then put together a full run down of my structural design. I'll probably have something done in the next couple of months which will go into great detail about most aspects of and pros and cons of my design choices.