still need a better hole shot...

[t_south91]

Dropped to a 17p 3 blade to help get my boat on plane (18ft 1985 sea sprite with OMC 3.8). It had made a tremendous difference when compared to the 21p piece of lead it came with. But...still isn't good enough when I want to slalom. I literally drink the lake for 30-40 seconds. I'm 6'5" 190lbs. So here's my question.

18p 4 blade or 19p 4 blade?

Love to hear other ideas! Thanks!

 

[alldodge]

Dropped to a 17p 3 blade to help get my boat on plane (18ft 1985 sea sprite with OMC 3.8). It had made a tremendous difference when compared to the 21p piece of lead it came with. But...still isn't good enough when I want to slalom. I literally drink the lake for 30-40 seconds. I'm 6'5" 190lbs. So here's my question.

18p 4 blade or 19p 4 blade?

Love to hear other ideas! Thanks!

You did better with the 17p 3 blade, going to an 18 or 19p, 3 or 4 blade is the wrong direction with what your wanting to do. Have you run a compression test to determine the status of your engine? If your engine is on it's last leg (even if running good) you may be fighting a loosing battle. What rpm are you turning at WOT without pulling anything?

 

[oldjeep]

When you go to a 4 blade you drop a pitch or 2, so you would be looking for a 15/16 4 blade. Honestly it sounds like you just need to work on your technique getting up.

 

[bilge rat jim]

When selecting a new prop, it's important to choose a prop that will allow your engine to run at or slightly below the manufacturers recommended WOT rpm. With your current prop, what rpms are you turning at WOT?

 

[jigngrub]

Have you considered JATO experimentation?

http://en.wikipedia.org/wiki/JATO

 

[steelespike]

Your lightly loaded rpm and gps speed would help determine your prop selection.
If your present lightly loaded rpm is well within the suggested range then then you would normally drop an inch of pitch going to a 4 blade
to maintain rpm.You will lose a little top end but hole shot would be improved.
Your 29 years old motor may be a ltitle tired or perhaps the foam under the floor has absorbed water over the years adding weight where it hurts the most.

 

[jestor68]

Dropped to a 17p 3 blade to help get my boat on plane (18ft 1985 sea sprite with OMC 3.8). It had made a tremendous difference when compared to the 21p piece of lead it came with. But...still isn't good enough when I want to slalom. I literally drink the lake for 30-40 seconds. I'm 6'5" 190lbs. So here's my question.

18p 4 blade or 19p 4 blade?



That 1985 3.8L V-6 probably doesn't have the power of a newer 3.0L I-4.

A tired motor can eventually rev up to the proper rpm when not pulling, but still not have the low end torque to pull up a slalom skier.

The next step is 15 pitch.

You can always start on two and drop one.

 

[MRS]

If you are right on the rpm's then you might want to try a set of tabs. I did add a set of SLT-10 tabs on mine 19ft 4.3. Cause I pull a tube a lot when we take friends with us tell what it made all the difference in the world bow stays down and boat comes on plane quick. Best thing I ever added to the boat....:thumb:

 

[dazk14]

1st get the rpm data. Those 4 bangers love 4 blades.

In the meantime for slalom skiing, leave the rope slack. Maybe 3-5ft..."Hit it". The boat will begin to move for a moment and you won't.

You'll have to play with the amount of slack, but you will get up much faster and the "yank" isn't a problem for anyone in decent shape.

Sorry for not being more specific, but it's been 40 years since I last used that technique and the I/skier would just eyeball it as the boat took up slack, and bark "Hit it". The motor would pull great once up.

The last boat it was used on was a 1973 Glastron GT150 with a 65 Evinrude running a cupped SST 21" pitch prop with zero hole shot. A 15" pitch prop would have worked nicely, but the boat would run 44mph and over-rev wildly with a 15. We were wayyy too lazy to switch props, and had already lost our drop ski in the ocean.

Good luck.

 

[jimbo_jwc]

After trying 4 different props on a 1987 3,0 L 130HP 4cyl. my boat liked for heavy loads a Solo's 14.5 X 17 4 blade alum , Original prop was mercury 14.5 X 17 3 blade alum.
Both of these props would exceed WOT rpms with 2 people and gear , food and beverages always full 24 gals of gas could exceed 5000 rpm . I tried another mercury 14.5 X 19 3 blade with the 2 people as before just a little less gas and beverages and could only hit 4200 rpm 36mph . It seemed that more pitch and blade surface area it would need more HP or less load to reach WOT . The last prop is the one I run mostly Its a mercury 14 X 19 3 blade stainless w/open big square vent holes .I like it for all round and with 4 people and gear WOT is 4600 rpm 39 mph . My boat likes the 1/2 less dia. . This is on a 196 Thompson Sea Rage Cutty Cabin 2300lb boat . GPS speeds on last 2 props and have yet to find mph and WOT with 4 blade 17 and 3 blade 19 inch pitch for light loads . you will need the trim tab that is smaller on some of these props ss and 4 blade . Hope this helps as I shopped .around all winter to get these at the right price and all boats handle different as you have larger motor and probably different gear ratio in lower unit .

 

[SkiDad]

i wonder if your ski is too small - i had trouble getting up on a skinny ski that was rated for someone 30 lbs lighter than me - got one of those Connelly shaped skis and I'm up very easy (cut my up time in 1/2) and I don't drag while up. I also use one of those deep V ropes still and that helps.

 

[jimbo_jwc]

You could drill to vent your lead sled prop for it doesn't work for you , previous post is large guy ,as I learned to ski slalom behind winner 75hp Chrysler with dropping a Cypress Garden Ski . I learned to get a second breath when my head was out rather than dropping and finding ski . Couldn't cut across wake till I got my first Connely ski that was concave some . At 58 yrs I haven't ski for a while

 

[t_south91]

Thanks for all the help guys!

Problem is my RPM gauge is not accurate...not sure how to make it accurate either. For example when I am idling it says the engine is idling at 2200 RPMs...NO WAY haha

I think it's just old and for its age it does pretty well. I appreciate all the input! I'm going to try a 15p 3 blade and see how that works.