Super long exhaust hose!

[smp]

Hi all. My exhaust hose is something like 15 feet long!!! And in need of replacement. And that stuff is expensive! I am concerned about the back-pressure issues with old hose and collapsed walls and buildup .. also the hose is cracking and old and the surveyor told me to replace it (he basically told me to replace all the hoses, which I've been doing everywhere else). I have no trouble with the engine so maybe I should leave well enough alone but I've only been motoring a maximum of two hours since getting the boat. I would like for everything to be in order with the new (to me) boat.

As you can see by the pics the exhaust hose runs all over the place. I would rather not replace 15 feet because it seems to me the run could be a lot shorter. Is there a reason that someone went through all that expense?

Below is a series of pictures showing the run from motor all the way through to the exit on the hull. Please have a look and let me know what you think.


The Atomic 4!


Just aft of the motor, you can see the water filter/separator (if that's what it is, no branding on it whatsoever) and you can make out the beginning of the exhaust hose as it comes off the waterlift muffler to the right of the image:


Exhaust hose as it travels back through a bulkhead just aft of the gas tank. You can see the copper fuel line that I would like to replace ... just because. I suppose I don't have to.


In this image you can see where the exhaust hose passes through the bulkhead, we're aft of that now. The steering mechanism is visible and you can make out that the exhaust hose is snaking it's way to starboard, it passes over that bulkhead rather than through the hole, which I imagine is there for ... the exhaust hose?


cont...

[smp]

Another look at that bulkhead with the exhaust hose passing over it:


Now from the lazarette (sp?):


Up and over and down to the exhaust fitting and out:


What do you think? Is there a need to replace all that hose or can I shorten the run? Could that long a run contribute to elevated back pressure? Like I said, I'm not experiencing any issues but i haven't even really "stretched it's legs" in the short amount of time I've used the motor.

As a side note, at idle I am coasting along pretty quickly! When motoring around my anchorage I have to go in and out of neutral to keep my speed down. Mostly out of gear coasting in neutral and only popping it into gear every 5 or 10 seconds. She's fast! Or needs different gearing.


I have another thread going in the fuel system section of the forum about that because it requires some work as well. Link here.

[sastanley]

smp..the hose needs to go above the waterline so it doesn't siphon when the engine is off. My hose run on my C-30 is 19 feet long. I bought two 10 foot sections and they are joined by a Centek fiberglass elbow in the sail locker above the waterline. I do not have any backpressure issues either. Your run does seem to be doing some extra snaking around, but it doesn't seem excessive..You are right though, at $7.50/ft it is expensive.

Another thing that needs to be added to your list is that yellow handled gate valve, which looks like a cockpit drain?? . They were never intended to be used in boats, yet the industry used them extensively in the 70's. The valve corrodes and often breaks inside, so then you cannot open & close it. At your next haul out, plan to replace any gate valves with at least a ball-valve, or better yet, a proper flanged seacock. I used marelon on my four thru-hulls, with a PVC or epoxied backerboard 5200'd to the hull.

There is a website that I can't get to at work (someone else post the link to MaineSail's site at pbase.com please!!!) which explains all that very well. Everything on his site is excellent & is a great read for newbie boat owners. It will help you avoid common pitfalls as you become more familiar with your boat's systems.

Do you have a tach installed? Any idea what RPM's you're spinning at idle? If properly tuned the A-4 can idle down around 600 RPM. Relatively high speed at idle could also indicate too much pitch in the prop.

[smp]

Thanks for the feedback!

I know about the gate valves .. that's why I replaced three others before launch! The raw water intake, the intake for the head and the drain from the sink in the head. All replaced with proper flanged seacocks. I couldn't get the groco flanged adapters locally. So far so good in any case. I plan to do the big cockpit drains next year when the boat is out of the water, it was too much to get done before launch this year. I did test the gate valves and they do close and open properly and I did replace the super old hoses that were attached to them. It'll have to do for this year.

When replacing the exhaust hose, I can do this with the boat in the water yes? The exhaust is just at the water line so I guess it'll be ok.

[sastanley]

Sure...you can do the exhaust hose as long as the hull fitting is above the water line..if you are worried about it, jam a soft wooden plug in it!

[smp]

Anyone care to guess what the ID of the hose is? I can't tell

[wmmulvey]

Here is the MAINSAIL link


http://www.pbase.com/mainecruising/boat_projects

Regards

Bill

[smp]

I actually followed his write up to do my thru-hulls. Maine Sail's site is super helpful.

[Mo]

I'd replace it just as it is there. The exhaust wasn't put on that like that because someone didn't want to cut hose. Someone knew how to keep water out of the engine. With bulkhead holes and cuts as you see there...not aftermarket...that was factory setup and C&C didn't loose engines over exhaust design.

You don't have to buy the hose from the Binnacle....I bought mine direct from an industrial rubber supplier here in Halifax, much less expensive...same product.

[sastanley]

wmmulvey, thanks!

smp..typically, exhaust hose is 1 5/8" ID. you'd better check though. It should be printed on the hose, but it may not be if it was 1977 hose like mine was...