Yet another Prop Question

[mv apollo]

Hello, I bought a 1999 Palm Beach 22 with 2000 Suzuki dt225 last year and it has a Solas 14 7/8 x 18 Stainless prop. Motor runs great but leaving harbor experienced "prop hub spun" as rpm's increased without speed increasing. I backed off throttle and took it up to plane very slowly(20 seconds) and hit 5000-5200 rpm and speed of 32-35 (Pacific ocean,2-3 swell and chop). I guess what I am asking is that is it possible for the hub to be slipping at full power and not too noticeable at reduced power? I have ordered a new prop from iboats(solas amita 14 x 17) to have while this one gets a new hub (if the forum agrees) and to use on my offshore runs where I would likely bring 300-500 lbs more in fuel,ice,gear and possibly human weight so I think the lower pitch is going to be correct. WOT is 5000-5600 recommended by manuf. Another question is how much does a new hub installed normally run so I don't get taken? Prop itself is in good condition. I have marked the hub/prop but need to test it on the water to verify if it is spun. Thanks in advance, Scott MV APOLLO

 

[gcboat]

Re: Yet another Prop Question

Here's some east coast pricing for your prop. And yes, they most definately can spin exactely as you mentioned. Weight, rpm's all are a factor.
http://www.properpitch.com/opr.asp

 

[kynolan2183]

Re: Yet another Prop Question

I think that a 17 pitch would run in the correct rpm range but what I don't get was the prop still acting like that or did it just happen once?

If it happened once then it can be a number of things and not just a spun prop.

Examples are the current chop you are driving in. Once a prop starts to suck air must times it will continue until you do something to stop it.
IE lower the unit, drop RPM ect.

I can make mine suck air and do it often when pulling a tuber for the dump the clutch feeling. Makes the rider put on the "primal fear smile" when it grabs at 5800 rpm.

 

[mv apollo]

Re: Yet another Prop Question

Hello, Thanks for your response. It seems to do it most at the harbor entrance where the water is often confused. When out on open water I seem to have to get on plane slowly or similar symptom but not as severe will occur. I looked at many posts about engine height/anti-vent plate...it is about 2-3 inches above transom bottom and transom has a step hull about one foot above that. I was only able to get 5200 rpm inside harbor WOT(ss 14 7/8 x 18) and that was without maximum gear that I would have on my offshore run hence the order for 17 pitch. The prop should be here by the weekend and I'll take notice of the rpm,speed and av plate. Thanks, Scott

 

[mv apollo]

Re: Yet another Prop Question

Hi, re-read your post and yes the prop would continue to over rev while boat would seem to slow down until I backed off the throttle, lowered trim and basically nursed it up to plane(20 second time). The water at the entrance was very rough and the bow was way up in the air. I did not mention that I have Bennett trim tabs (hydraulic-manual) but I was told to trim them when the motor was already on plane...is that correct? Appreciate the help, Scott

 

[steelespike]

Re: Yet another Prop Question

Hi, re-read your post and yes the prop would continue to over rev while boat would seem to slow down until I backed off the throttle, lowered trim and basically nursed it up to plane(20 second time). The water at the entrance was very rough and the bow was way up in the air. I did not mention that I have Bennett trim tabs (hydraulic-manual) but I was told to trim them when the motor was already on plane...is that correct? Appreciate the help, Scott

I think it is obvious your on the edge with your setup so if your in salt you may want to be sure your bottom,gearcase and prop are in ideal condition.

I'm no tab expert but I think they meant to fine tune the tabs after you are on plane.I think you need some +tabs to help you plane exccesive tabs might agrivate venting.Too little tabs delays planing.Be sure you trim motor in all the way to plane easier.then adjust motor and tabs for the best performance.

 

[mv apollo]

Re: Yet another Prop Question

Thanks, I will try some trim tabs and then adjust them. Also when I test drove the boat it was in a lake with a moderate >1 foot chop. I didn't notice any excessive plane time,bow rise or slipping and WOT produced 41-42 mph at 5200 rpm. The boat was empty with 10 gal. fuel 2 adults and 135 lb child. Thinking about all of times it slips it is when I go full throttle leaving harbor in chop and usually going into the wind and swell. I will take the new prop and take notice of all symptoms and post outcomes. Thanks, Scott