Volvo Penta D3-130

[Jonathan2021]

it sounds like trim tabs could help - but its a relatively expensive thing to try if it doesnt make a significant difference.

I may just have to swallo the cost and risk. I imagine a set of Bennet tabs is the

An interesting experiment would be to try one size larger props, but practically, it's difficult to "borrow" props and buying them would be an expensive experiment, unless you can find someone else with a similar boat that has the same setup.

regretabbly on aprox 14 ever made. I have asked a few people to borrow some props for a fee and they declined. To be fair im

have a look at smart tabs - google them.

I've never used them, but a lot of people (admittedly with smaller boats) swear by them for improving planing behaviour .

They're like trim tabs, but they're not controllable by the driver, they are mounted on some passive some spring rams that allow them to constantly apply an amount of pressure. They're cheaper than regular trim tabs as a result, but less useful too (ie they cant compensate for uneven port to starboard loads)

thanks will have a look. They sound promising

 

[Jonathan2021]

An interesting experiment would be to try one size larger props, but practically, it's difficult to "borrow" props and buying them would be an expensive experiment, unless you can find someone else with a similar boat that has the same setup.

I have tried to borrow a pair of props but I was declined and to be fair I don’t blame them. It is a hassle. I’m going to a few boat jumbles…. You never know what a prop god may provide ?

 

[Jonathan2021]

have a look at smart tabs - google them.

I've never used them, but a lot of people (admittedly with smaller boats) swear by them for improving planing behaviour .

They're like trim tabs, but they're not controllable by the driver, they are mounted on some passive some spring rams that allow them to constantly apply an amount of pressure. They're cheaper than regular trim tabs as a result, but less useful too (ie they cant compensate for uneven port to starboard loads)

I will do thank you!

 

[gordmac]

Is it worth running it through a prop calc programme? Assuming 4000rpm is the max and you hit that fully loaded I would guess lightly loaded it would be under propped.

 

[QBhoy]

Diesel seems fine. I treat it for diesel bug so that should not be a issue

No worries. But wouldn’t rule it out. Often treatment can disturb sediment and all sorts that once lay harmless. But then can restrict the fuel. I’d try running her off a small Jerry can of known fresh diesel, to rule things out.

 

[Jonathan2021]

Is it worth running it through a prop calc programme? Assuming 4000rpm is the max and you hit that fully loaded I would guess lightly loaded it would be under propped.

I had never considered that it could be under propped. I wonder who could do such a calculation

 

[Jonathan2021]

No worries. But wouldn’t rule it out. Often treatment can disturb sediment and all sorts that once lay harmless. But then can restrict the fuel. I’d try running her off a small Jerry can of known fresh diesel, to rule things out.

You could be right and it would,d be nice to be absolutely sure and cover the basics

 

[gordmac]

I had never considered that it could be under propped. I wonder who could do such a calculation

Google it, there are some online.

 

[Momac]

What speed is the boat doing at 4000rpm?

 

[QBhoy]

True .
Just throwing normal boost p about.It seems low .As said around 1.7/1.8 bar running is very common.Even small petrols Fiat uno , Renault 5 s etc

Those cars never ran anything like that pressure of boost. Certain of it. Not out the factory anyway.

 

[QBhoy]

If you are only getting 3000 rpm wot…you’re not over propped for sure. Unless the props have been messed with or this was a diy finished set up…VP boats are usually well propped from new.
what props are on her now ?

 

[SC35]

If you are only getting 3000 rpm wot…you’re not over propped for sure. Unless the props have been messed with or this was a diy finished set up…VP boats are usually well propped from new.
what props are on her now ?

Read the original message again << not meant in a stroppy way >>
My interpretation is that hitting the stops on the throttles from start results in 3000rpm, a massive wake, and a load of bubbles.
Then after a period of time, maybe a couple of minutes, it it over the hump and gets planing, max rpm 4000rpm.
Take a look at the torque curve I posted up earlier to see why this might be happening.

It looks as if it's hitting the hull hump speed exactly at the point at which the torque drops off, which isn't a good thing from a performance point of view.

 

[QBhoy]

Read the original message again << not meant in a stroppy way >>
My interpretation is that hitting the stops on the throttles from start results in 3000rpm, a massive wake, and a load of bubbles.
Then after a period of time, maybe a couple of minutes, it it over the hump and gets planing, max rpm 4000rpm.
Take a look at the torque curve I posted up earlier to see why this might be happening.

It looks as if it's hitting the hull hump speed exactly at the point at which the torque drops off, which isn't a good thing from a performance point of view.

Got you and understood. Yeah. Seems to be the case right enough.

 

[Durley245]

Hi everyone,

does anyone here have common knowledge of the Volvo Penta D3 range?
Would anyone know if there are any internal differences through the power range or is it a matter of Tuning?
We recently purchased a Sunline Discovery 31 and are really struggling with planing and having enough power when she's fuelled up and few adults on board......
We keep minimum stuff on board.
Twin Engines were recently serviced and the Hull cleaned and anti fouled and is currently running Volvo 4 blade props with 1.66 gear ratio on SX stern drives
WOT is 3000rpm with 14.5 psi but once on the plane it revs to 4000rpm happily
Planing is a huge huge struggle!
We have been told that our setup may be underpowered for the sea and its possible the boat has a river set up. Not sure if this true or not....
Any help would be appreciated

Jonathon 2021, I spoke to you last year about your Sunline 31. As you know I manufacture the boat as the Quayline 31. I have tested one in Spain Sunline 31 without tabs with the twin Mercruiser 120 fitted.

Top speed was 25 knots ( with 2 people on board. Relatively clean hull.
It planned at 12 knots
It weight is 4,250 kg with this installation.
Volvo supply standard props. Manufacturers usually end up buying an additional set to suit the particular design.

Changing props and trim tabs will help. I am fitting tabs on new ones, despite the claim from the designer it does not need them.

If you want 30 knots plus you need 2x 200hp each or more. So it's techically underpowered at 260hp.

Be nice to view it when in your area.

 

[gordmac]

Seems good performance from only 240hp, I presume a relatively low vee design?

 

[Durley245]

Seems good performance from only 240hp, I presume a relatively low vee design?

Seems good performance from only 240hp, I presume a relatively low vee design?

Yes, I would agree. It's been designed to achieve this , plus I forgot to mention is the SX Duoprop version if fitted would also help a great deal in this installation.

 

[SC35]

As a comparison, my previous S28 weighed 4,400kg - with twin KAD32's at 170hp, it would plane quickly and keep going until about 34kts.

 

[BartW]

Hi there,

Our Karnic 2660 with 2 x D3-190 , weighes nearly the same like your Sunline,
she goes very easy on the plane,
the original spec of this boat was 2 x 160, we got the 190's on special order,
to our experience the 4 blade props give the best performance,
your rpm 's and turbo proessure looks ok,

so yes, I'm afraid your boat is underpowered,
from all the sugestions, the trimtaps might give a slight improvement,
while the smarttaps, might be ok, You'd better go for full controll able trimtaps sa Bennett,
at least you have some settings to play with.

sorry no better advice,
good luck with It !

anticipate to upgrade for another boat

 

[Jonathan2021]

What speed is the boat doing at 4000rpm?

26 knts

 

[Jonathan2021]

Hi there,

Our Karnic 2660 with 2 x D3-190 , weighes nearly the same like your Sunline,
she goes very easy on the plane,
the original spec of this boat was 2 x 160, we got the 190's on special order,
to our experience the 4 blade props give the best performance,
your rpm 's and turbo proessure looks ok,

so yes, I'm afraid your boat is underpowered,
from all the sugestions, the trimtaps might give a slight improvement,
while the smarttaps, might be ok, You'd better go for full controll able trimtaps sa Bennett,
at least you have some settings to play with.

sorry no better advice,
good luck with It !

anticipate to upgrade for another boat

Thanks for your advic. Appreciate it