prop slippage

[holtzoo]

I have a heavy 22' boat with a 200 mercury 2 stroke I have a 1.87 gear ratio a 4 blade 14.75 by 18 I'm running 5300 wot my range is 5000-5600 so thats good at wot my gps is 30kts I went and did the bam slippage cal. it said I had 38% slippage how can I get that lower,I'm guessing my engine will run more eff. Thanks

 

[BaileysBoat]

Re: prop slippage

Your slip is actually 28.6%. With more info we might be able to help.

 

[Faztbullet]

Re: prop slippage

I have a heavy 22' boat

With 20+% slip it sounds like either a deep vee hull or bay boat as these never really get on plane and owners use to much positive trim to try and lift nose boat.

 

[tpenfield]

Re: prop slippage

I get a fairly high slippage with my deep V boat. The fact that your boat is 'heavy' is probably the biggest issue.

Is there anything that can be easily done to take some weight out?

 

[steelespike]

Re: prop slippage

I got 28% as well.
Tell us the brand year and model of the boat and motor.Describe performance hole shot in seconds,lowest cruising rpm and speed.Is the bottom clean and smooth?Prop in excellent condition?

 

[holtzoo]

Re: prop slippage

It is a 1987 chapparrel 224 fisherman with a 2004 mercury 200 I'm not sure of how many seconds for hole shot but with my 14.75 by 18 4 blade prop and trim tabs down I think my hole shot pretty good ,my bottom has bottom paint that is almost half gone(Don't want to repaint it so I'm trying to where it of)my cruise rpm around 3500-4000 speed is about 20-25 kts prop is new Thanks

 

[Bondo]

Re: prop slippage

It is a 1987 chapparrel 224 fisherman with a 2004 mercury 200 I'm not sure of how many seconds for hole shot but with my 14.75 by 18 4 blade prop and trim tabs down I think my hole shot pretty good ,my bottom has bottom paint that is almost half gone(Don't want to repaint it so I'm trying to where it of)my cruise rpm around 3500-4000 speed is about 20-25 kts prop is new Thanks

Ayuh,.... Is this now a trailer boat, or still a dock queen....

If it's still a moored boat,...
My guess is yer draggin' 'round alotta sea life with ya to get down to 28% slip...

 

[holtzoo]

Re: prop slippage

It's always been a trailer boat the prev. owner painted the hull but it never sat in the water I don't know why he painted it ( I'm friends with with him.

 

[steelespike]

Re: prop slippage

I wouldn't call your boat heavy unless your running an amazing amount of gear or people.Boat is 3000 lbs,reasonable for 200 hp.
I checked a few tests of similar weight boats and one 5200lb boat.5200 had 16% slip the rest were between 15 and 12%.
All the boats ran over 40 mph. So the rub is your speed. You might try another gps or be sure you are indeed measuring knots.
Next varify the tach is accurate against another tach. Your slip at 3500/20 mph is about 37% and 4000 produces about 32%
reasonable in relation to 5300 as slip usually goes down as rpm and speed increase. The question is it real slip or is your rpm really lower
or your real speed higher.You good hole shot would seem to indicate the prop is working well.