Exhaust flange or glassed tube ?

[LuSea]

I have both options available in my shop for my 6" exhaust. B/A bronze flange or 6"glass tube. I've been thinking in the direction of the glassed in tube with only one joint on the outlet side of my muffler being a silicone coupling. I'm really liking the idea of no flange fasteners , one less coupling and a flared exhaust exit. Am I missing anything important by not using the bronze flange ?

 

[plowin]

I prefer a flange. I have seen plenty of chewed up exhaust tube tails chewed up from shit banging off of them.

 

[WoundUpMarine]

Stainless flange. Easier and looks better IMO.

 

[tunafishhkg]

If you go with flange on a cored hull, make sure it has been de-cored and glassed preferably for 1-2" radius not just filled. Over time any underwater joint will leak I find LOL

 

[kapnd]

If you go with flange on a cored hull, make sure it has been de-cored and glassed preferably for 1-2" radius not just filled. Over time any underwater joint will leak I find LOL

Good advice, and true whether you use a flange or a tube through.
Best to assume that it will take some heavy hits and overbuild.

 

[leaky]

I think anything you got should be the lowest profile possible, ie flush with hull as much as practical, then it's not gonna see much abuse in the first place.

To me always seems a liability to have a sub waterline appendage there, especially a fiberglass based one that's essentially glued in place if you think about it.

Glassing something in its real tempting to have the tube partly outside the hull as it gives you someplace that's easier to tab to. But it doesn't need to be done that way either - it can end up quite flush.

It's not a bad thing to have some flexibility in the exhaust system. In my mind - you really shouldn't have a fiberglass tube running the length of half the hull, glassed in like it's a structural member.. And then if it's not actually permanently part of the hull, say its only passively mechanically attached, it seems odd to make the outlet end permanent. If I was gonna glass the outlet, I'd still have a coupling there - let the transom flex without pushing on the entire exhaust system.

 

[tunafishhkg]

I think anything you got should be the lowest profile possible, ie flush with hull as much as practical, then it's not gonna see much abuse in the first place.

To me always seems a liability to have a sub waterline appendage there, especially a fiberglass based one that's essentially glued in place if you think about it.

Glassing something in its real tempting to have the tube partly outside the hull as it gives you someplace that's easier to tab to. But it doesn't need to be done that way either - it can end up quite flush.

It's not a bad thing to have some flexibility in the exhaust system. In my mind - you really shouldn't have a fiberglass tube running the length of half the hull, glassed in like it's a structural member.. And then if it's not actually permanently part of the hull, say its only passively mechanically attached, it seems odd to make the outlet end permanent. If I was gonna glass the outlet, I'd still have a coupling there - let the transom flex without pushing on the entire exhaust system.

Always use the shortest length stub at transom as well as any bend points! Also best to have the joints accessible at all times or at least viewable, worst case, have a planned point to cut an access AND use best materials IE silicon hose at coupling.

 

[hardcore1]

I ve had a few boats now with the tube glassed from the transom to the exhaust elbow. Never seen an issue or a crack. This is what I prefer as it's simple, streamlined and no clamps. I've seen lots of leaky exhaust clamps over the years. They can easily sink a boat

 

[[email protected]]

Both types have their up and downsides. Accessibility from the inside and which look I like is what would make me chose one over the other. Mine has the glass tube and the hose went on when the boat had no deck yet. Years later when I went to replace the hose to it I could reach the clamps, pull the old hose but it was tough getting the new one on.
Wet exhaust is an interesting thing. It's the largest thru hull in the boat but has no seacock and an interuption in raw water flow can take out rubber hose pretty quick. I put on a raw water flow alarm and it works really well. It'll chirp on and off while I'm dumping non tox into the strainer because it's slower flow than regular pick up. On the other side of things, if I fished offshore I'd add that Y to the raw water pump that allows it to pull water from inside the boat

 

[tunafishhkg]

I went with a pacer pump for emergency pump out because I think in the chaos of an emergency, an engine pump out system takes time to get sorted out with seacocks even though it should not, oil rags normally this bilge area, Not really a high flow rate given other options, plus you got to worry about flow for cooling engine.

 

[leaky]

I went with a pacer pump for emergency pump out because I think in the chaos of an emergency, an engine pump out system takes time to get sorted out with seacocks even though it should not, oil rags normally this bilge area, Not really a high flow rate given other options, plus you got to worry about flow for cooling engine.

Those big rule 4000s are pretty powerful and practical. My last boat, I had one of those pumps around and installed it on a simple on/toggle.

I stuffed one that literally filled the cockpit to the point it rolled out over the transom. To stabilize the boat we opened the hatches, let it down into the bilge - that pump made quick work of getting it out.

Of course you gotta have battery power to pull it off, but you gotta have battery power to start your engine too - possibly to run it if it's a modern engine. Like you, I don't see the engine water pump as the end all solution.

High water alarms, also good and important.

What we are talking about here with exhaust, the couple times I've seen failures it was an older boat, owners bought them and never touched the exhaust, then years later some 20+ year old component was leaking. One case it was 8 inch hardwall exhaust hose clamped w/ regular worm gear clamps, in a place that had poor access, and really all it did leak a little, never would have sunk the boat. Another case a muffler failed by coming apart at the seams - it wasn't even accessible, deck had to be cut out to replace.

Anyway I feel like a quality coupler, with quality clamps, is pretty damn safe even if only inspected (replaced as needed) every few years. It's the 20+ year old stuff buried and taken for granted that sinks boats.

 

[kapnd]

I ve had a few boats now with the tube glassed from the transom to the exhaust elbow. Never seen an issue or a crack. This is what I prefer as it's simple, streamlined and no clamps. I've seen lots of leaky exhaust clamps over the years. They can easily sink a boat

Roger that, Captain!
I prefer solid glassed exhaust systems too, no droops to trap water, no clamps to fail, no hidden rubber joints, just a hump hose off the elbow, and guaranteed downslope drainage.

 

[[email protected]]

I went with a pacer pump for emergency pump out because I think in the chaos of an emergency, an engine pump out system takes time to get sorted out with seacocks even though it should not, oil rags normally this bilge area, Not really a high flow rate given other options, plus you got to worry about flow for cooling engine.

To be clear I'm not saying you shouldn't have bilge pumps. I'm just saying that the engine makes a good cheap emergency pump. How big is the inlet hose on the pacer pump, 2" with a seperate motor? the little Cummins B is 2". Rev it up and it moves a lot of water, let alone what a Cat C18 could move. lots of pump for almost no extra plumbing and loose rags will clog any pump. If theres water nothing is overheating. But I would'nt take the Pacer out if it was already in. Batteries underwater are batteries submerged whether it's high capacity Rule pumps or ECM's. And if we are talking about a Pacer gas pump, that's 1 whole different engine to maintain and hope starts when the time comes.

 

[leaky]

How big is the inlet hose on the pacer pump? the little Cummins B is 2". Rev it up and it moves a lot of water, let alone what a Cat C18 could move. lots of pump for almost no extra plumbing and loose rags will clog any pump. If theres water nothing is overheating.

I think you probably got good flow.

Issue in my mind is more, you got a problem, now you are stressed and down in the bilge messing w/ plumbing to fix it that's probably also underwater.

That same plumbing designed to let you pump out could also sink your boat or destroy your engine waterpump, engine even, if it is misused or fails somehow.

A separate electric pump is a pump and outlet, a switch on your bulkhead - at least as simple as a couple valves to turn your engine supply to the bilge. You get stressed, you flip a switch to turn it on. I don't know what he means by pacer though, could be electric, hydraulic, or a complete combustion engine trash pump the way I understand the term.

 

[tunafishhkg]

Its 2" and being centrifugal, I believe puts out more than a vane pump but all boats can not always go the same route so in terms of safety when it hits the fan, all options can be crucial. Agree on loose rags and why I rather have engine not overheat to add to situation. If the amount an engine flows keep up to save you, the redundant pumps already always in the arsenal should but of course more the better ALWAYS!

 

[kapnd]

Using your raw water pump as a bilge pump should be a last resort measure, certainly not a substitute for proper bilge pumps.
All it costs is a tee and a valve, I’ve got one, and hope to never have to use it!

 

[[email protected]]

I think you probably got good flow.

Issue in my mind is more, you got a problem, now you are stressed and down in the bilge messing w/ plumbing to fix it that's probably also underwater.

That same plumbing designed to let you pump out could also sink your boat or destroy your engine waterpump, engine even, if it is misused or fails somehow.

A separate electric pump is a pump and outlet, a switch on your bulkhead - at least as simple as a couple valves to turn your engine supply to the bilge. You get stressed, you flip a switch to turn it on. I don't know what he means by pacer though, could be electric, hydraulic, or a complete combustion engine trash pump the way I understand the term.

They are either hydraulic SAE take off drive, like a Cummins raw water pump requiring the main engine, or seperate drive requiring a "pony" engine/motor. So in the time it's needed you can move valves or start a seperate engine.

 

[[email protected]]

And why is the main engine overheating? It doesn't care if it's raw water flow is coming fom inside or outside the boat. This wasn't meant to be the only way to survive offshore. I was just saying that with a single screw boat you can put in a hell of an emergency pump for about $150. See it in huge Carolina sportfishes all the time.

 

[leaky]

And why is the main engine overheating? It doesn't care if it's raw water flow is coming fom inside or outside the boat. This wasn't meant to be the only way to survive offshore. I was just saying that with a single screw boat you can put in a hell of an emergency pump for about $150. See it in huge Carolina sportfishes all the time.

I'm pretty sure he means if you successfully evacuate the water, eventually you gotta stop pumping your cooling water from the bilge.

 

[Quik Fix 16]

Easy peasy. Saved me one late night at the dock. "Jerry, is the boat horn supposed to be on?" Have high water switch wired to horn.