Black exhaust streaks on underside of hull.

[Driver]

Hello,

My Volvo D9s in my Pearl 50 show no obvious smoke or problems when running. However, I notice black streaks running back from the underwater exhausts, nearly to the transom, the same on both sides and about the same width as the exhaust outlet. Never seen that before. But then I have never had white antifouling (semi abradable) before either. The engines do get quite a lot of running at 1000 rpm. Any comments, please?

 

[jrudge]

I would say a bit of soot is normal.

 

[rafiki_]

Hello,

My Volvo D9s in my Pearl 50 show no obvious smoke or problems when running. However, I notice black streaks running back from the underwater exhausts, nearly to the transom, the same on both sides and about the same width as the exhaust outlet. Never seen that before. But then I have never had white antifouling (semi abradable) before either. The engines do get quite a lot of running at 1000 rpm. Any comments, please?

Are your props clear of fouling? When my props were fouled then I got a lot of soot on the transom.

 

[Bouba]

I remember getting black streaks from through holes that have no connection to the motor... and I wondered if it’s to do with stray current or something....I put some insulation around electrical wires close to the seacocks and it seemed to cure it

 

[kashurst]

I used to get grey streaks down the sides, close to the water line, on my T50 with under water exhausts with D9s. If everything is other wise OK I wouldnt worry.
I stopped using white antifoul as it seems to encourage underwater growth.

 

[Driver]

The props are reasonably clear and there is no soot on the transom. I did read the threads about antifouling colours, but when I considered changing from white, her indoors burst into tears and said it would spoil the colour scheme. It would.

 

[harvey38]

The props are reasonably clear and there is no soot on the transom. I did read the threads about antifouling colours, but when I considered changing from white, her indoors burst into tears and said it would spoil the colour scheme. It would.

Happy wife, quiet life.

Nuff said!

 

[DAW]

I would say a bit of soot is normal.

I agree. I have D13s and over time I get traces of soot accumulating on both sides of the hull just above and behind the main underwater exhaust outlets. Most of the boats in our marina have this. Obviously with black antifoul you don’t see the accumulation below the waterline. I would say if you can see the soot in the exhaust gas, or notice a marked change after a single trip, then further investigation is warranted, but a gradual and light accumulation over the course of a season would for me be normal.

 

[Driver]

Thanks for your comments, guys, set my mind at rest.