Reply
 
Thread Tools Search this Thread
 
Old 24 March 2007, 18:54   #1
alt
Member
 
Country: Ireland
Town: Galway, West Eire
Make: Cranchi
Length: 5m +
Engine: 2 x Volvo KAD300
Join Date: May 2006
Posts: 644
Send a message via MSN to alt
What props have I got? (Volvo duoprop)

Hi guys,
Currently running a Volvo KAD32 with duo props. The problem is that she should be achieving 3700 - 3900RPM WOT but i'm only getting 3000RPM, i'm obviously over pitching.

The only code I could find on my props was A5F 854778, which was on the forward prop

Can anyone shed some light on what pitch props I have? Or know a database online where I can find out??

Many thanks in advance!
__________________

__________________
alt is offline   Reply With Quote
Old 24 March 2007, 19:03   #2
alt
Member
 
Country: Ireland
Town: Galway, West Eire
Make: Cranchi
Length: 5m +
Engine: 2 x Volvo KAD300
Join Date: May 2006
Posts: 644
Send a message via MSN to alt
Found a bit of information here: http://www.volvo.com/vce/vebiz2webau...0Volvo%20Penta

I've found the prop's that I have, but what I can't fingure is whether to move up to the A6 or move down to the A4 etc...

Any guru's out there?!
__________________

__________________
alt is offline   Reply With Quote
Old 24 March 2007, 19:42   #3
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Alt, I can't tell you what to move to, but A4 has less pitch than A6. Can you speak to the previous owner and find out whether the engine has never reached correct revs? If it performed satisfactorily for them, there may be a different reason for the current lack of performance.

You need to find the number on the rear prop. I have seen Volvo drives fitted with props of mixed pitches and it seriously damages the performance.

Going down from A5 to just A4 is not enough to regain 800revs.
__________________
JW.
jwalker is offline   Reply With Quote
Old 25 March 2007, 04:52   #4
alt
Member
 
Country: Ireland
Town: Galway, West Eire
Make: Cranchi
Length: 5m +
Engine: 2 x Volvo KAD300
Join Date: May 2006
Posts: 644
Send a message via MSN to alt
Thank's j. Unfortunately, the previous owner isin't all that well informed. Most his answers were 'I left it to the engineer'.

I asked him what RPM he was getting at WOT, he said 'Cant remember but I was hitting 33 knots". I'm getting 33knots at 3000RPM

I realise going down to A4 from A5 isin't going to give me 800RPM, i'd just love to know how much RPM difference there will be by moving each A (ie. would A5 to A4 give me an extra 200/300/400 RPM)
__________________
alt is offline   Reply With Quote
Old 25 March 2007, 08:50   #5
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Alt, you need the power curve to find out what power you're getting at 3000rpm and then an estimation of the correct prop can be made. Volvo prop sets are not cheap, it can be an expensive buisiness. Volvo have a technical department and they will put your numbers into a computer program which will give you your props specification. However, I found it not too accurate for a rib. I felt I could guess better.

I'll see if I can find the phone number for you.
__________________
JW.
jwalker is offline   Reply With Quote
Old 25 March 2007, 09:25   #6
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Here ya go.

Phone 01923 228 544 ask to speak to John Glenny for a prop calculation. My guess is A3s and 36knts if your drive is 1.95:1. Note, I did say guess....

Here are your power curves and engine perfomance data.
You can see you will get another 25hp approx by proping to 3800rpm. Presently, you are substantially overloading your engine. The data shows 136hp at the prop for 3000rpm full load but for normal use it should be only 89hp. Also your fuel consumption is way higher than it needs to be.
Attached Thumbnails
Click image for larger version

Name:	Kad32 power x800.jpg
Views:	2217
Size:	85.5 KB
ID:	25671   Click image for larger version

Name:	KAD 32 tech data x800.jpg
Views:	3089
Size:	95.7 KB
ID:	25672  
__________________
JW.
jwalker is offline   Reply With Quote
Old 25 March 2007, 09:45   #7
Member
 
Country: UK - England
Town: Mighty Penryn
Boat name: Little Joe.
Make: Avon Searider
Length: 4m +
Engine: Honda BF50
Join Date: Aug 2005
Posts: 8,841
Quote:
Originally Posted by alt View Post
Hi guys,
Currently running a Volvo KAD32 with duo props. The problem is that she should be achieving 3700 - 3900RPM WOT but i'm only getting 3000RPM, i'm obviously over pitching.

The only code I could find on my props was A5F 854778, which was on the forward prop

Can anyone shed some light on what pitch props I have? Or know a database online where I can find out??

Many thanks in advance!
I doubt whether prop pitch is your problem. If it were so over-propped as to be losing 900rpm it would struggle to even get on the plane. Surely this would have been addressed at some point in the past. I'd take a look at other reasons in the engine dept. Those things have electronic rev. limiters which are prone to playing up.
Or, possibly, the guy you bought it from has nicked the correct props off of it and put the original fitments back on. Do the props look newish?
__________________
Mollers is offline   Reply With Quote
Old 25 March 2007, 09:53   #8
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Quote:
Originally Posted by Mollers View Post
.. If it were so over-propped as to be losing 900rpm it would struggle to even get on the plane.
You would think so but when I was setting up my boat I had exactly the same problem as Alt, but worse. I could only pull 2700rpm and flat out at 27knts. but it lifted onto the plane smoothly and easily. I agree though, checking everything else before spending money is a good idea.
__________________
JW.
jwalker is offline   Reply With Quote
Old 25 March 2007, 10:01   #9
Member
 
Country: UK - England
Town: Mighty Penryn
Boat name: Little Joe.
Make: Avon Searider
Length: 4m +
Engine: Honda BF50
Join Date: Aug 2005
Posts: 8,841
Quote:
Originally Posted by jwalker View Post
You would think so but when I was setting up my boat I had exactly the same problem as Alt, but worse. I could only pull 2700rpm and flat out at 27knts. but it lifted onto the plane smoothly and easily. I agree though, checking everything else before spending money is a good idea.
But is Alts's labouring at 3000rpm or just refusing to rev any higher? Just to add to the confusion, those DP's run a different pitch on each prop. It may only be one that is wrong. I wonder if the previous ower is genuinely thick or being a bit cagey.
__________________
Mollers is offline   Reply With Quote
Old 25 March 2007, 10:03   #10
Member
 
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,962
Quote:
Originally Posted by Mollers View Post
Just to add to the confusion, those DP's run a different pitch on each prop. It may only be one that is wrong.
Yeh, I know, I mentioned that in my first post but 800rpm is a lot to lose.
__________________

__________________
JW.
jwalker is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 02:34.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.