1GM10 advice please

[sailorbaz]

We took the boat out at the weekend - it's a Boomaroo 25 with lifting keel which is an Aussie built Catalina 25 - engine driving a 3 blade prop. We left our fore and aft mooring in the creek at 6am - still dark here - the engine started first push which it always does. Checked for water out with exhaust and OK. As we got under way a bit of steam in the exhaust. Thought this might be due to low air temp, about 6°C. Once out of the creek opened it up but could only get 2000 rpm max and more steam. As it got light we could see black liquid in spurts in the exhaust water. Had a search on the forum on our iPad and conclusion was unburnt diesel in exhaust probably due to fouled prop. Laying down in the dinghy I can see the prop and it does have quite a bit of barnacle growth on it.
Does the team think this would be enough to cause the lack of revs and the unburnt diesel? Is the steam another problem?
The shaft turns freely by hand from inside the boat.
TIA for any help
Sailorbaz

 

[srp]

I've had exactly the same symptoms several times - usually on the last sail of the season in Oct/Nov en-route to the boatyard. Low temp in early morning gives the steam (nothing to worry about if the water is flowing). Any sort of barnacle growth on my prop gives black smoke and reduced revs.

 

[Appledore]

Any sort of barnacle growth on my prop gives black smoke and reduced revs.

+1

My boat was underused last season and would hardly move when I moved her off the mooring (Yanmar 1 gm 10). The barnacles on the prop were thick, and black smoke, low revs and steam! See picture link.

https://lh3.googleusercontent.com/-9fkad_Avud8/Toh5g7CXzCI/AAAAAAAAB3s/sLAYIGk7BGA/s640/DSCF4361.JPG

 

[greggron]

Wow. Never knew that. Thanks for this, it accounts for some of this behaviour at the end of last season.

 

[NUTMEG]

+1

Had same probs last season. Black smoke, black oily grungy stuff mixed with exhaust water. Scrubbed hull and polished prop, problem solved!

 

[sailorbaz]

Thanks for the replies. I hoped that was what it was. I thought it couldn't be too serious as I could rev it to over 3000 rpm in neutral and no black stuff in the exhaust.
Sailorbaz

 

[Niander]

Is there a prop in there...

 

[Burnham Bob]

i don't have the black smoke problem but barnacles were colonising my prop and performance was falling off towards the end of the season. in fact boat speed was severely reduced. coating the prop with trilux 33 solved the problem

 

[zikzik]

i don't have the black smoke problem but barnacles were colonising my prop and performance was falling off towards the end of the season. in fact boat speed was severely reduced. coating the prop with trilux 33 solved the problem

Is this an antifoul? When I bought my Contessa 26 last year (same engine & 3 blade prop), the prop was painted with white antifoul. I wondered why. This might be the reason!
N