Bav 40 J & J - Vetus Wet Exhaust Hose specs

[MagicalArmchair]

I am cursed to be nothing but a burden to this community - thank you for all your help - in the coming years I will make it my quest to pay it all forwards.

On checking the steering of Mirage, I noted this:





Yup, someone's bodged up the thing that runs poisonous gas and water through the boat with gaffa tape and lo, it's got a hole in it where its blown through. I do have carbon monoxide alarms in the boat, but it's still sobering that my daughter was sleeping in the cabin just forward of this bodge.

I want to order the replacement hose before I go down to the boat to replace it. I presume its 65mm Vetus hose -- but how long to get back to the waterlock? Does anyone know the length of this hose?

edit: The boat has the D2-55

[Yngmar]

It's easy to measure by running a tape measure parallel to the hose. But before you do that, check the markings - some of them have meter marks printed on them!

Once you look up the price per meter of wet exhaust hose, you'll learn why the PO bodged it rather than replace! 

I figure it's also acceptable to join a piece with a hose connector and double hoseclamps.

[Keweetoo]

If you still have the original exhaust water lock/silencer fitted with the two chrome end caps its probably worth replacing whilst your doing the pipe with a plastic one (as the original will inevitably start to leak at some stage)  or allow some extra hose length so you will be able to replace in the future. I found the out take from the new plastic silencer was higher and needed a bit of juggling to fit as my hose was only just long enough so allow an extra half metre.

[Symphony]

Think you will find the hose is 57mm (if you have a Volvo rubber and stainless endcap muffler). If the rest of the hose to the muffler is sound, would suggest just replacing from the patched bit to the exhaust outlet using a joining piece of stainless or plastic tube. The gases and water are almost cold and not under much pressure at that point. If you do replace the whole lot then you will find the new hose much more flexible than the old so easier to get into place. Agree with the suggestion to replace the Volvo muffler as they have a relatively short life. However, the most suitable, the Vetus WLOCK type is only available with 60mm spigots. Good information on exhaust systems on the Vetus site. Halyard Marine are also a good source for exhausts and they have some good GRP water trap mufflers as well as hose and fittings.

[Markus]

One more addition to this topic: make sure to check very carefully that the hose is well strapped down all the way. As the water from the engine is pushed out of the system periodically by the exhaust gases, the whole exhaust pipe is subject to considerable "surges" and given a chance to move it will quickly abrade itself against the fiberglass. Looking at your picture, it may well be possible that rubbing against the stringer edge was the cause for failure...

[MagicalArmchair]

I've measured the hose this afternoon over lunch, and the length aft of the muffler is circa 4.3m, forward to the exhaust elbow is about 60cm, and the hose measured 58mm I/D (as you suggest Symphony, likely 57mm stretched). The muffler looks in good nick for now, so I'll keep it as is and revisit when there are fewer things I am screwing the hell back together.

The challenge here is I can't get 58mm hose anywhere, I can get 60mm hose. Will that clamp down securely onto the 58mm hose tails? It is pretty bendy stuff!

[Yngmar]

It's bendy, but the double stainless steel spiral reinforcement makes it pretty difficult to compress.

And as Symphony pointed out, it's 57mm, which I can find several UK sources for, including https://www.hoseworld.com/57mm-2-1-4-i-d-corrugated-marine-diesel-exhaust-hose-cmdeh-057.html

Also, just spotted that ASAP supplies has GRP hose connectors, which is possibly the best material for this job: https://www.asap-supplies.com/products/centek-straight-grp-exhaust-hose-connector-57mm-hose-200mm-length-c-1200679

[Symphony]

Vetus also list it  vetus-shop.com/vetus-marine-exhaust-hose-id-57mm-p-511.html

[Salty]

In addition to the Vetus plastic exhaust silencers, Force 4 chandlery also sell an unbranded plastic silencer which has tapered inlet and outlet plastic pipes. You just cut off the bits of pipe that are too small and connect your hose to the bit thats the right size. The silencer last time I looked was priced at about £65, and Ive had one in place now for several years. The Vetus will cost you some £40 more.

[Yngmar]

In defense of the original Volvo silencer, I've taken ours to bits last winter (after all the tales of rotten ones here) and was pleasantly surprised that it only had very minor corrosion. I cleaned it up, then reassembled it with high temperature silicone on all the joints, which should prevent any further crevice corrosion.

I'm not too fond of the plastic ones, having seen in person what happens when they melt after running dry for a short while -- a big hole venting steam and exhaust fumes into the boat. There are fiberglass ones which should resist heat much better, but they're a bit hard to get and pricey.

[MagicalArmchair]

I had a peer inside the silencer when I took the exhaust off to measure the ID and it looked in pretty good and shiny fettle, so I'll leave alone for now. The exhaust elbow has a bit of rust on it though, hmmm. Might get myself a stainless replacement for that over this winter (edit: wow, this guy: https://www.parts4engines.com/volvo-penta-d2-55a-and-d2-55b-stainless-steel-exhaust-outlet-and-connector/) .





Vetus 57mm hose on order - given how easy it came off the muffler, I am less concerned about how hard the job will be. Is there some cladding or chafe guarding I can put around the hose to protect it from chafing at the point it likely rubbed through last time?

[elias]

I have also a d2 55 with the Volvo silencer . Is take it out and weld where I found unhealthy spots . My welder- mechanic will build one for me this year as a spare with almost half the price .
I ve seen horrible engine rooms after the plastic silencer melted ...

[Symphony]

On my old wooden boat the exhaust hose ran over the top of wooden frames and I glued pieces of neoprene from an old wetsuit to the frames to prevent chafing.

The problem with the Volvo silencer is the fundamental design of the outlet end cap which has the outlet tube welded in at an acute angle. The tube has to be permanently under water to form the waterlock. This includes the weld, particularly the underside of the tube to the end cap. It is very difficult to achieve a good clean weld without inclusions in this location, and there is no way of testing whether the weld is sound. If there are inclusions  they provide a perfect spot for crevice corrosion to start - submerged in oxygen starved salt water. The life of these silencers, or more properly the aft end cap is largely determined at the point of manufacture, which is why some last for many, many, years if the weld is good. As I recounted last year, the one in my 2015 boat failed after less than 3 years with the classic pinholes forming on the outside of the cap below the outlet pipe. Unfortunately Volvo won't sell just the end cap, so £350+ for a complete silencer. I have since had a plate welded around the outlet pipe of the original at a cost of £40 so have a spare should the new one fail.

I think it wise to inspect the underside of the outlet pipe to end plate regularly and if there is any sign of pitting, get it welded up before it actually perforates. Not the easiest thing to inspect - you need a torch and a mirror.

[MagicalArmchair]

Thanks Symphony, I'll see what old bits of rubber I have floating around. I could wrap some silicone tape (effectively lag) that section to provide a barrier on the pipe itself to chafe and then some of this on the parts of the boat that rub against it?

https://jimmygreen.com/protect-chafe-tape/11076-protect-chafe-tape

What was the wooden boat you had? My father had a beautiful 1930's gaff cutter called Wanda (https://youtu.be/QeBPzE-MByA). I may disassemble the silencer and take a peer inside for any pitting. Is it just a case on undoing the big jubilee clips?

[Symphony]

Doubt you will see much inside as the weld will be covered with dirt from exhaust gases in the water and because of the angle it is almost impossible to see the critical part of the weld anyway. I am looking at the failed one now and even though it has been cleaned up a bit there is no sign of the pinholes inside. However, it was very obvious outside as once you get a pin hole the lower part of the end cap gets stained very quickly. Just difficult to see when the silencer is in place. As the silencer is always half full of water you need to remove it from the boat before you take the caps off otherwise you get 3l or so of dirty seawater in the bilge! If you do take it off you will appreciate why it is so difficult to check the original weld, which is done from the outside, hence my comment that early failure like mine is determined at the point of manufacture. The way to increase life is to drain it if you are not using the boat, but this is really impractical without removing it.

My wooden boat was a 1963 Eventide 26 called Tranona which I owned from 1980 until last year. Professionally built by the same builder who went on to build the Golden Hinds. Superb boat which I refitted twice, first time in 1992 building a new deeper keel and rudder and extending the coachroof. Two changes of engine from Stuart Turner to Yanmar 1GM then Nanni 14. Last refit included laying a teak deck (never again!). Toss up whether to keep it or the 33 but commonsense won and I sold it last year. In fact I was finishing her off in Davis's yard last year when you brought Mirage in there. Not in the same league as Wanda, but took me all over the channel, northern France and Channel Islands.

[Symphony]

Photo of Tranona

[MagicalArmchair]

Note to self: Some jobs are too meaty to fit into 20 minutes of lunch break  .

I took the old hose out, no trouble, cut the new hose to the length of the old hose, plus a few inches for good measure laying the hoses out next to each other on the pontoon to put the chafe guards in the right place, proceeded to fit, and lo! It's too flipping short

It routes all the way around, albeit a bit tight on the clamps (The OD of this hose is much thicker than the old hose), however, I cannot get the support on the last bit of hose travelling down to the skin fitting. So it 'floats' down to the skin fitting - its the below clamp I can't get on. The clamp at the TOP of the swans neck is in place (it was a pain to get on).



I'm a bit worried its pulled a bit tight around the clamps to match the old run also, however, I'm guessing this Vetus hose is pretty tough stuff.

Options are:

• Lengthen the section from the engine to the silencer to give that extra foot of hose I need (I had planned to replace that anyway). This will put the hose under less pressure at bends etc where currently its pulled less tight. It would mean screwing the silencer supports on a bit further aft.
• Forget about it and rather than clamp the hose at that point, use so cable ties on it with some rubber around it to prevent the cable tie sawing through the pipe.

I didn't get any photos as I just ran the hell out of time.

[Symphony]

The fixed points are the hull outlet and the silencer outlet, so remove the clamps, attach hose to the hull outlet, form the loop and see where the hose runs. You may then be able to attach the other end to the silencer and reposition the intermediate clamp(s).

[MagicalArmchair]

The two fixed points are fine and it makes the right shape (the loop above the waterline), and of the 5 supports for the hose, only that last one won't quite reach. Its not rubbing anything there and is well supported aloft at the top of the 'swans neck' - I might just cable tie it on the last support... it feels like a bit of a bodge and its not beautiful but it won't leak gas, it will be safe, and it will last.

[MagicalArmchair]

In other news, thanks for the photo of Tranona. A mighty vessel to do all those miles! Were you laying the teak deck on plywood, or was it a straight replacement? (How I remember the drips on my head when sleeping on Wanda!  )

[Symphony]

The deck was ply. I bought a job lot of 50* 4mm teak from Howells - just enough to do the whole deck and coachroof. It was a choice of either that or sheathing it as it was a constant battle to deal with water getting into the joins in the ply. They were butt joints on deck beams rather than scarfed, so if water did get in it would eventually get into the beams. Over the years I became expert at using epoxy, glass and veneers to fashion repairs! However I underestimated the sheer amount of back breaking work gluing the strips down with Saba and then filling the seams. Final result, however was OK and no leaks.

Fortunately the hull was sheathed in Cascover from new and was mostly sound. The mast had been in the rack for 9 years and needed stripping down to bare wood. It was hollow Douglas fir and was as sound as the day it was made. Coated with Sikkens Cetol, much the same as was on previously which had lasted nearly 20 years. All the gear on the boat was the best I could buy, but as is the way these days I sold it for less than the cost of the new Nanni installation. At least it went to a good home and now lives in S Wales.

The original owner lived in Salcombe and kept the boat on a mooring at the bottom of his garden. He was even more adventurous than me, going to Ireland and through the Brittany canals then back round the outside. I have all his original accounts of the 6 summers he owned her. Earlier this year out of the blue his son contacted me and we had a wonderful exchange of emails and photos and general nostalgia. Part of me wishes I had kept her but realistically I don't think I could have coped with the ongoing work, nor living in the relatively primitive accommodation (even though I lived on board for getting on for a year in the early 80's).

As you have no doubt discovered with Mirage, modern boats have so much to offer in terms of comfortable living and sheer practicality, even if their aesthetics and "real" sailing ability might be less satisfying than older designs. Bit like cars, which is why I have a Morgan for my trips down memory lane!

[MagicalArmchair]

A lot of work, skill and time went into that boat - I'm sure she gave it all back though.

Back to the matter at hand. I think I have cracked it in a way that I am satisfied with, even it the pipe is an inch short. All the standard clamps are on apart from the one at the top of the swans neck. That is held on with cable ties. I will put some antichafe up there (I have one of the kids old wet suits eyed up for that).

On each of the clamps I have put the original rubber antichafe and some silicone tape to hold it all in place. From the engine, back we have:



First clamp:



Second clamp coming up to the swans neck above the water line. There is plenty of scope here for chafe, and here it had rubbed through previously to the stainless spiral, so I added some extra rubber in here to try and prevent that.



Top of the swans neck. I'll chop these cable ties when I'm at anchor next and put something in to stop the cable ties from having the opportunity to saw through the pipe over time:



Final clamp to the skin fitting:



To the skin fitting itself:



I took a look at the old pipe, and it had rubbed through to the spiral in multiple places from chafe, so it was a ticking time bomb, so I'm glad I've done the job.