Props different sizes

[capthorace]

Well another finding on my 28CC. I had a lower unit leaking oil from the trim seals , so it was time to get it fixed before major damage. Had the boat hauled and this is what I found. Port unit props were B5 / B6, Stb Unit was B6 / B5. The mechanic made a statement that he had never driven a CC (and thats a ton) that was as fast and responsive as this one. This was before we found the different wheels. I asked about getting another set of props and he said it will not hurt anything and it runs great WHY CHANGE!
Has anybody else done this?

[seatime]

What kind of power are you running in your boat? I have just ordered B7's for my 28 because it turned the B6's up way too high.

[ClassicStile]

Speaking of props, I have a '98 28 CC with the Volvo KAMD 42's.....mechanic busted a prop doing some outdrive work and ordered me a whole new set of props from Volvo....

What is the recommended pitch and diameter on the Volvo props for this boat and power combination?? Does anyone know or can you point me to a reference source to get the info (maybe Mac or Keith can answer)?

I noticed I lost about 3 knots at cruising RPMs (3400) with the new props thrown on the outdrives....only did about 22kts vs 25kts....which is significant when you're running to the canyon....

Any suggestions?

Thx

[Captain Spike]

Speaking of props, I have a '98 28 CC with the Volvo KAMD 42's.....mechanic busted a prop doing some outdrive work and ordered me a whole new set of props from Volvo....

What is the recommended pitch and diameter on the Volvo props for this boat and power combination?? Does anyone know or can you point me to a reference source to get the info (maybe Mac or Keith can answer)?

I noticed I lost about 3 knots at cruising RPMs (3400) with the new props thrown on the outdrives....only did about 22kts vs 25kts....which is significant when you're running to the canyon....

Any suggestions?

Thx

I have KAD43's and I have B6 props fitted, 3400 RPM = 25 Knots

[Axiom2000]

I wish I knew how you guys were getting 25 kts. out of these boats. I have a 2002 28 with tower KAMD43P's straight inboards, 550 hours. Lightly loaded clean bottom in the right conditions I may see the gps indicate almost 25 kts at WOT but that is rare and I would never run her that hard for long however. My manual tells me WOT RPM should be between 3700 and 3900 both motors will turn 3800 and hold it with no issues, the props are what came on it from the factory and I have them scanned every season. I generally run her between 3400 and 3500 making about 22kts. However fully loaded for a canyon trip 20 is more like it until I burn off some fuel.
Not complaining mind you I knew when I bought her she was not going to be fastest boat at the marina and I love the ride, fuel economy and dependability of these motors, although they are a bit loud.

[Captain Spike]

I wish I knew how you guys were getting 25 kts. out of these boats. I have a 2002 28 with tower KAMD43P's straight inboards, 550 hours. Lightly loaded clean bottom in the right conditions I may see the gps indicate almost 25 kts at WOT but that is rare and I would never run her that hard for long however. My manual tells me WOT RPM should be between 3700 and 3900 both motors will turn 3800 and hold it with no issues, the props are what came on it from the factory and I have them scanned every season. I generally run her between 3400 and 3500 making about 22kts. However fully loaded for a canyon trip 20 is more like it until I burn off some fuel.
Not complaining mind you I knew when I bought her she was not going to be fastest boat at the marina and I love the ride, fuel economy and dependability of these motors, although they are a bit loud.

Classicstyle & myself have outdrives, mine is Duoprop and I presume his is also. That might account for the difference. I see 22 Knots at 3100 RPM, 24 - 25 Knots at 3400 RPM and WOT about 3850 - 3900 is 32 - 33 Knots depending on load. I've seen 34 Knots on the GPS a couple of times.

[backman]

xiom - something is wrong

I had KAMD42's for 6 years; turned 3800 WOT w/ 17 X 23 Hi Torq's w/ #2 cup.

I was unhappy that at 3250 I could only make 22 knots and had to go up to 3400 to get to the magic 24 knots where the hull started to slip. I would get 29+ knots WOT. My engines were 98's; had 2100 hr's when I sold them and even at their smoky end; with one injector on one side fried; on my last trip home I still made 24 knots @ 3400.

[Axiom2000]

Thanks, I either got a heavy boat or my GPS is wrong, when it gets back above 17 degrees around here and I get her back in the water I will check it against the Hand Held GPS, don't know why I ever thought of that.

[Split Decision]

Axiom

One other thing to check is how smooth your bottom paint is. I ran my 32 the first year with the factory paint and was getting 26kts at 2700 rpm and top out at 30kts. After I painted it the next year (with a 3/8" nap roller) I could not get 24kts at 2700 and top out at 27.5 kts. Mac said I need to get the paint on smooth using a 1/4" foam roller. This year I will sand the bottom smooth and repaint with the foam roller and thin the paint so it goes on smoother.

[Axiom2000]

Hey good idea, I have noticed the bottom paint looks a bit rough, I was plainning on have it all soda blasted off this spring anyway as I am sure there are 5 or 6 coats on there.
Thanks again
Jerry

[capthorace]

95 -28cc

I have gas 7.4's with duo props B6, 3100 = 28kts on GPS. My props are also painted with prop speed which seems to make a difference.