Volvo penta D6 435hp D rating

[Mazenardati]

Hi Every one,
First Post here, New member

Iv been struggling with a Princess 43, as i have been experiencing some D Rating issues, with the volvo penta D6 435hp, when we got the boat here to Dubai, it was doing 28knts @ 3500 RPM, after we sold it by a month or so, it was going a max of 20KNTS @ 3100 RPM, i have been head to head with volvo penta, they have replaced the boost sensors (same issue) they did a software update (Same issue), and they dont know what to do, as they boat has been commissions with the issue in progress (So any data gathered after this point will simply show the engines are in 100% full load), they ended up saying it needs to be lifted and given a high pressure hull clean up, i checked the hull, its practically good as new
i suspect it is the fuel quality as it is on both engines.

note: this happened in a single night not gradually, i can replace the veem interceptor inserts, from orange and white to blue, but i dont think it will solve the problem


Any one experienced anything like this before

Thank you for your help
Read more at http://www.ybw.com/forums/showthrea...-435-D-Rating-Princess-43#zJZghhVFMJoxusRO.99

 

[Cruless]

Will the engines Rev up to max rpm when not in gear?

 

[aquapower]

Will the engines Rev up to max rpm when not in gear?

They will be limited to 1500 when in neutral.

 

[Cruless]

Apologies I do not work in the marine industry I work in with large generators usually powered by Volvo D , cummins as or catapillar engines. I suspect a fuelling problem if it's affecting both engines or an electronic control issue ,

 

[Anders_P42]

When you say hull was checked, was it lifted and checked for growth? Are props clean?

Or could fuel temperature be getting too warm?

 

[Mazenardati]

Hi guys,
Well if it is a fuel problem, what might it be? Both engines are brand new, i could not see any growth, and if it was a growth problem, then that would have slowed the boat down, within a certain period amount of time, a year for instance, not in a single day!
Has this happened to you Cruless?

Thanks for the help.

 

[Cruless]

The only similar issue I have had was I had 2 cummins generators that were running low on power. After trying everything I found the main fuel feed (3 months old ) had collapsed internally restricting the flow.

 

[jfm]

This is hard to diagnose. Some random ideas:

The boat has been sold and is in commission. Had the owner added a lot of weight? Big tender? Can you nearly empty the fuel tanks (1 tonne), and the water tank (0.5 tonne), and see what speed you get? I don't know how weight sensitive p43 is (both kg and position of those kg)

2. Do you have airflow? Are the engine room fans working? Has the weather/temperature changed since you got the 3500rpm and 28kts? Can you do a test run at 5am or whenever it is coolest? And with cool fuel (remembering that by taking the fuel tanks down to say 25% you are going to increase the fuel temperature, unfortunately, so measure your data early in the run before the amount of warm returned fuel has heated up all the fuel in the tanks)

3. Did it happen after a fuel fill? Could it be bad fuel or is your fuel quality good?

 

[aquapower]

Could have something to do with the water temp, have had this before when sending a uk built and commissioned boat to Thailand where water temp was around 30 degrees, after a conversation with Clements and providing data from the owner they came up with a different prop size which cured the problem.

 

[volvopaul]

Could have something to do with the water temp, have had this before when sending a uk built and commissioned boat to Thailand where water temp was around 30 degrees, after a conversation with Clements and providing data from the owner they came up with a different prop size which cured the problem.

The hotter climate will certainly have an effect on the overall performance, but here in the UK Princess and a Volvo dealer had a lot on tweaking and number crunching to get the 43 going properly somewhere near the speed the brochure advertises, this is a big boat for the D6 engine that's the reson why the cummins unit is now available in the 43.

I doubt boost sensors and engine components wil sort the speed issue, the Rev drop is down to load being read by the engines brain, some prop tweaking may help but you won't get anywhere near the top speed the boat can attain in a colder climate.

 

[jfm]

you won't get anywhere near the top speed the boat can attain in a colder climate.

He is comparing speed he got in Dubai on one day with speed he got the next day. An overnight change. Unless the weather changed overnight there, as I asked him, it cannot be a "UK boat goes to Dubai" problem. I'm only going on the symptoms exactly as reported of course!