Import Manager
05-01-2004, 07:05 AM
#0, Right Props?
Posted by Dos Locos on Mar-30-04 at 08:52 AM
I recently purchased a 23' Albacore Special with an AQD-40A and 280 DP. The previous owner had it on the market for quite a while because the performance was not very good (13kts cruise, 17 wide open at 3400 RPM with 12 psi turbo boost). I liked the boat and made him an offer knowing I would probably have to re-power, and got a good deal. I have since sorted out a number of obvious issues and now the boat runs at 3600 RPM wide open, 21.5 kts loaded and 15 psi boost. The engine seems to produce adequate power and the boat accellerates quickly to top speed without excessive exhaust smoke or vapor from the oil breather. The question now; are the A4 props currently on the boat the right props? One of the BOCA members posted a link to Volvo's propeller applications which shows this engine/outdrive combo should have A5 through A10 props. Anyone have experience with this? Also, what would be a reasonable cruise RPM for this engine to start with.
Bob Mills
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#1, RE: Right Props?
Posted by NoSlack on Mar-30-04 at 09:42 AM
In response to message #0
Bob
Let me get a little more info on the boat.
Do you know the gear ratio for the lower unit? 2.30:1 or 1:98:1
Is the engine an AQD-40A(135 HP) or an AQAD-40A(155 HP)? The difference will be an aftercooler on the AQAD.
What's the engine temp at 3200 RPM and how high does it clime if you leave it at 3600 for a few minutes?
Cap. Art runs a 290DP with A5 props on his 23', with an AQAD40A engine and tops out around 29 knots. I think he gets 23 or 24 knots at 3200.
I went with the 2.30:1 lower end when I converted my 280 to a DP this winter. I have an AQAD40A as well and found A7 props to be a good fit for those gears. I top out at 26 knots turning 3600 RPM with no increase in engine temp(180 degrees). I cruse at 19.5 to 20 knots at 3200 RPM with the temp in the 175 degree range.
Mike
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#2, RE: Right Props?
Posted by moo fish on Mar-30-04 at 11:22 AM
In response to message #1
Great!! Another 23 footer!!
Propping is black magic and experimenting with different props. Good luck...
My question is what "obvious issues" did you resolve to get such an increase in performance?
rt
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#4, RE: Right Props?
Posted by Dos Locos on Mar-30-04 at 12:59 PM
In response to message #2
RT,
The obvious issue began with the props. The forward prop had two bent blades and both props had gobbs of rough bottom paint. I stripped the old paint and straightened and dressed the props the best I could in my shop. Because the previous owner had not done any engine work in the years he had it, other than oil and filter charges, I had the injectors rebuilt and installed a boost gauge to is if the induction system was up to par. I also found that the lead/wire seal on trottle stop on the injestion pump had been removed long ago and the stop screw had been turned in to keep the RPMs lower than 3600. A diesel mechanic told me to try screwing it back out alittle to see what happens. It took some oil and a bit of tapping with a hammer, but it broke loose and I screwed it out about four turns to get the 3600 RPMs. The boat was used a long time ago for swordfishing, so I can only assume that may have had something to do with the deliberate power reduction and A4 props.
Bob
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#3, RE: Right Props?
Posted by Dos Locos on Mar-30-04 at 12:30 PM
In response to message #1
Hi Mike,
I wouldn't stake my life on it, but it should be a 2.30:1 according to the owners manual. Is there a way to tell? It is the AQD-40A 130 or 135 hp, non-aftercooled. The coolant temp remains at 180F at all higher RPM ranges.
Bob
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#8, RE: Right Props?
Posted by NoSlack on Mar-30-04 at 07:40 PM
In response to message #3
From the info you gave I think it's a safe bet to say you're running 2.30:1 gears. You should be able to check the ratio by removing the top cover on the upper gearbox. Turn the props 1 full turn and the shaft you see under the cover will make 2.3 revolutions.
If you feel you heat exchanger is clean and performing as good as can be exspected for a 20+ year boat, 180 degrees is a good place to be. If you can bring the coolant temp down 10 degrees by cleaning the heat exchanger, then you might have room to run a set of A5 props.
I wouldn't spend $600 on a new set for testing, but if you can borrow a set or pick them up cheap on ebay, it's worth a try to see what they will.
Mike
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#5, RE: Right Props?
Posted by Yellowfin1 on Mar-30-04 at 02:47 PM
In response to message #0
Bob,
Mike (No Slack) is the man when it comes to these questions. I have a 26 billfisher with the AQAD-40B (165HP) and the Duo Prop. I am running an A-7 which was re-pitched to an A-6 pitch. I was getting 15-16knots at cruise (3300 RPM) and 17-18KTS at 3600 RPM for what it's worth. Although, I'm hoping to upgrade in power soon.
Good luck,
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#6, RE: Right Props?
Posted by Wizard on Mar-30-04 at 03:06 PM
In response to message #5
LAST EDITED ON Mar-30-04 AT 03:09 PM (PST)
Mike is the man to talk to about props, most of us agree. He has gone through the exercise to it's fullest on a 23'.
I've been through it with my 26' and learned a lot as well.
I posted the following link before which shows the Volvo Penta latest charts. Here it is again. It confirms about A6 or A7 for your engine and gear ratio. But everything Mike says about your engine temp etc is important.
http://www.penta.volvo.se/files/45uk2001.pdf
For example, I run B4s on a 26' Blackman, KAD42, 1:78.
I might be interested in trying your A4s if you move up. Mike and I have talked about the differences in the past. I have an A4 rear prop to test, but if it works better, would want an A4 set, if in reasonable shape.
Glenn
"The Reel One"
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#7, RE: Right Props?
Posted by moo fish on Mar-30-04 at 06:01 PM
In response to message #6
Quick--there is a set of A5's on eBay.
rt
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#9, RE: Right Props?
Posted by Dos Locos on Mar-31-04 at 08:32 AM
In response to message #7
Thanks to all for the insight. Mike, at some point a heat exchanger from an AQAD or similar was installed. I assume it has greater cooler capabilities because it's about 4" longer than the original I saw in the shop manual. With this combination, it's possible a lower temp therostat could bring the temp down from 180. As it is now, the temp never goes above 180. I am not certain of the actual time on the engine. The previous owner said it was under 2000 hours. The hour meter, which looks like the original VDO, indicates under 1600 hours.
BTW, other projects I've done in the last couple of months was the installation of a K series Floscan and replaced the original Benmar 21 SK autopilot with the Raymarine Smart Pilot. If anyone would like insight on these projects, let me know. Also if anyone needs the old Benmar, they are welcome to it. It was working when I took it out.
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#10, RE: Right Props?
Posted by noquestion25 on Mar-31-04 at 01:00 PM
In response to message #9
I am intrested in the autopilot, I have a 23 outerbanks that would greatly benifit from it. Let me know how I could get ahold of you.
No Question (Josh)
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#11, RE: Right Props?
Posted by NoSlack on Mar-31-04 at 03:21 PM
In response to message #10
Make sure you guys have the same type of steering, cable or hydraulic.
Benmar units came either way but won't do you any good it you get the wrong one.
Benmar still services the old units if you need to get it tuned up.
Mike
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#12, RE: Right Props?
Posted by noquestion25 on Apr-01-04 at 05:08 PM
In response to message #11
Thanks for that info Mike. I very easiley could have found myself pulling my hair out, or even converting my cable to hydraulic. I guess I need to find out which unit he has.
Josh
Posted by Dos Locos on Mar-30-04 at 08:52 AM
I recently purchased a 23' Albacore Special with an AQD-40A and 280 DP. The previous owner had it on the market for quite a while because the performance was not very good (13kts cruise, 17 wide open at 3400 RPM with 12 psi turbo boost). I liked the boat and made him an offer knowing I would probably have to re-power, and got a good deal. I have since sorted out a number of obvious issues and now the boat runs at 3600 RPM wide open, 21.5 kts loaded and 15 psi boost. The engine seems to produce adequate power and the boat accellerates quickly to top speed without excessive exhaust smoke or vapor from the oil breather. The question now; are the A4 props currently on the boat the right props? One of the BOCA members posted a link to Volvo's propeller applications which shows this engine/outdrive combo should have A5 through A10 props. Anyone have experience with this? Also, what would be a reasonable cruise RPM for this engine to start with.
Bob Mills
--------------------------------------------------------------------------------
#1, RE: Right Props?
Posted by NoSlack on Mar-30-04 at 09:42 AM
In response to message #0
Bob
Let me get a little more info on the boat.
Do you know the gear ratio for the lower unit? 2.30:1 or 1:98:1
Is the engine an AQD-40A(135 HP) or an AQAD-40A(155 HP)? The difference will be an aftercooler on the AQAD.
What's the engine temp at 3200 RPM and how high does it clime if you leave it at 3600 for a few minutes?
Cap. Art runs a 290DP with A5 props on his 23', with an AQAD40A engine and tops out around 29 knots. I think he gets 23 or 24 knots at 3200.
I went with the 2.30:1 lower end when I converted my 280 to a DP this winter. I have an AQAD40A as well and found A7 props to be a good fit for those gears. I top out at 26 knots turning 3600 RPM with no increase in engine temp(180 degrees). I cruse at 19.5 to 20 knots at 3200 RPM with the temp in the 175 degree range.
Mike
--------------------------------------------------------------------------------
#2, RE: Right Props?
Posted by moo fish on Mar-30-04 at 11:22 AM
In response to message #1
Great!! Another 23 footer!!
Propping is black magic and experimenting with different props. Good luck...
My question is what "obvious issues" did you resolve to get such an increase in performance?
rt
--------------------------------------------------------------------------------
#4, RE: Right Props?
Posted by Dos Locos on Mar-30-04 at 12:59 PM
In response to message #2
RT,
The obvious issue began with the props. The forward prop had two bent blades and both props had gobbs of rough bottom paint. I stripped the old paint and straightened and dressed the props the best I could in my shop. Because the previous owner had not done any engine work in the years he had it, other than oil and filter charges, I had the injectors rebuilt and installed a boost gauge to is if the induction system was up to par. I also found that the lead/wire seal on trottle stop on the injestion pump had been removed long ago and the stop screw had been turned in to keep the RPMs lower than 3600. A diesel mechanic told me to try screwing it back out alittle to see what happens. It took some oil and a bit of tapping with a hammer, but it broke loose and I screwed it out about four turns to get the 3600 RPMs. The boat was used a long time ago for swordfishing, so I can only assume that may have had something to do with the deliberate power reduction and A4 props.
Bob
--------------------------------------------------------------------------------
#3, RE: Right Props?
Posted by Dos Locos on Mar-30-04 at 12:30 PM
In response to message #1
Hi Mike,
I wouldn't stake my life on it, but it should be a 2.30:1 according to the owners manual. Is there a way to tell? It is the AQD-40A 130 or 135 hp, non-aftercooled. The coolant temp remains at 180F at all higher RPM ranges.
Bob
--------------------------------------------------------------------------------
#8, RE: Right Props?
Posted by NoSlack on Mar-30-04 at 07:40 PM
In response to message #3
From the info you gave I think it's a safe bet to say you're running 2.30:1 gears. You should be able to check the ratio by removing the top cover on the upper gearbox. Turn the props 1 full turn and the shaft you see under the cover will make 2.3 revolutions.
If you feel you heat exchanger is clean and performing as good as can be exspected for a 20+ year boat, 180 degrees is a good place to be. If you can bring the coolant temp down 10 degrees by cleaning the heat exchanger, then you might have room to run a set of A5 props.
I wouldn't spend $600 on a new set for testing, but if you can borrow a set or pick them up cheap on ebay, it's worth a try to see what they will.
Mike
--------------------------------------------------------------------------------
#5, RE: Right Props?
Posted by Yellowfin1 on Mar-30-04 at 02:47 PM
In response to message #0
Bob,
Mike (No Slack) is the man when it comes to these questions. I have a 26 billfisher with the AQAD-40B (165HP) and the Duo Prop. I am running an A-7 which was re-pitched to an A-6 pitch. I was getting 15-16knots at cruise (3300 RPM) and 17-18KTS at 3600 RPM for what it's worth. Although, I'm hoping to upgrade in power soon.
Good luck,
--------------------------------------------------------------------------------
#6, RE: Right Props?
Posted by Wizard on Mar-30-04 at 03:06 PM
In response to message #5
LAST EDITED ON Mar-30-04 AT 03:09 PM (PST)
Mike is the man to talk to about props, most of us agree. He has gone through the exercise to it's fullest on a 23'.
I've been through it with my 26' and learned a lot as well.
I posted the following link before which shows the Volvo Penta latest charts. Here it is again. It confirms about A6 or A7 for your engine and gear ratio. But everything Mike says about your engine temp etc is important.
http://www.penta.volvo.se/files/45uk2001.pdf
For example, I run B4s on a 26' Blackman, KAD42, 1:78.
I might be interested in trying your A4s if you move up. Mike and I have talked about the differences in the past. I have an A4 rear prop to test, but if it works better, would want an A4 set, if in reasonable shape.
Glenn
"The Reel One"
--------------------------------------------------------------------------------
#7, RE: Right Props?
Posted by moo fish on Mar-30-04 at 06:01 PM
In response to message #6
Quick--there is a set of A5's on eBay.
rt
--------------------------------------------------------------------------------
#9, RE: Right Props?
Posted by Dos Locos on Mar-31-04 at 08:32 AM
In response to message #7
Thanks to all for the insight. Mike, at some point a heat exchanger from an AQAD or similar was installed. I assume it has greater cooler capabilities because it's about 4" longer than the original I saw in the shop manual. With this combination, it's possible a lower temp therostat could bring the temp down from 180. As it is now, the temp never goes above 180. I am not certain of the actual time on the engine. The previous owner said it was under 2000 hours. The hour meter, which looks like the original VDO, indicates under 1600 hours.
BTW, other projects I've done in the last couple of months was the installation of a K series Floscan and replaced the original Benmar 21 SK autopilot with the Raymarine Smart Pilot. If anyone would like insight on these projects, let me know. Also if anyone needs the old Benmar, they are welcome to it. It was working when I took it out.
--------------------------------------------------------------------------------
#10, RE: Right Props?
Posted by noquestion25 on Mar-31-04 at 01:00 PM
In response to message #9
I am intrested in the autopilot, I have a 23 outerbanks that would greatly benifit from it. Let me know how I could get ahold of you.
No Question (Josh)
--------------------------------------------------------------------------------
#11, RE: Right Props?
Posted by NoSlack on Mar-31-04 at 03:21 PM
In response to message #10
Make sure you guys have the same type of steering, cable or hydraulic.
Benmar units came either way but won't do you any good it you get the wrong one.
Benmar still services the old units if you need to get it tuned up.
Mike
--------------------------------------------------------------------------------
#12, RE: Right Props?
Posted by noquestion25 on Apr-01-04 at 05:08 PM
In response to message #11
Thanks for that info Mike. I very easiley could have found myself pulling my hair out, or even converting my cable to hydraulic. I guess I need to find out which unit he has.
Josh