Drop in pitch versus Smart Tabs

[codertimt]

Okay guys. I know this type of question has been posted before, and I've read many different discussions...but as every scenario is slightly different I wanted to get some opinions on my particular case. I try to lay everything out in an easy to read list...

• 2007 Glastron GT 185 - 4.3 Mercruiser - 1.81 ratio - 23" stock AL prop
• Empty with just driver = 4800rpm at 52-53 gps mph
• Light family load(2 adults/3kids/gear) = 4600rpm 47 gps mph. Weight distribution was towards the bow and could not trim all the way without ventilating prop. I'm assuming that's why the drastic drop in speed...
• Heavy family load(4 adults/3 kids/gear, probably within 200lbs of max weight) = barely 4400rpm. No verified speed.
• Will sometime have family load right at max weight.
• Main goal is I need single ski pulling power. I am willing to sacrifice speed/fuel economy.

So that's the basics. I tried to ski for the first time in 5 years and it was a struggle getting up. A lot of the issue is that I'm currently 250 and out of shape...I'm starting to work on that. But I was hoping for more from the 4.3. Here is a clip of the pull if interested. I'm quite rusty...and the faceplant at the end verifies that. Plus that was the third attempt before getting up...and my back leg was cramping...and...okay, so I'm out of practice and need to accept that...

http://www.youtube.com/watch?v=Mn3NEqCoveA

Anyway, it seems like I have rpms to work with when loaded. I was thinking of dropping down to a 21", probably 4 blade. I will never be out cruising by myself, so that can be thrown out of the picture. I would have to watch my rpms while lightly loaded, but I don't think that would be too big of deal since the only time I seem myself needing 50mph if I was outrunning a storm or something...

I was pretty set on the above, but then started reading about Smart Tabs again. I'm sure I would like them and all of the benefits they give, but I'm just afraid they're not going to give me the extra pull I'm wanting when loaded, especially since the Glastron hull really does a great job of keeping the bow down by itself. And it's not like I'm turning 4800 with a typical load or anything either...

I had also though about attempting to put vent holes in the current prop. But was thinking that wasn't terribly effective on I/Os...

Anyway, so I'd love some opinions from the prop experts and from smart tab users with before and after experiences pulling slalom skiers.

I'd also like to tag on another question for the prop experts. Does anyone know if a prop of a mid-80s inline6 Mercury outboard would fit an Alpha 1? I know the diameter is smaller, but that's about it...

 

[TomP]

Re: Drop in pitch versus Smart Tabs

I am not one of the experts on this forum, but I do have a boat similar to yours (Cobalt 190, 18.5 feet, 4.3L V6, 205 hp, Alpha One drive, 2,823 lbs dry weight). I don't have experience with the Smart Tabs, but I do think you would benefit from dropping the pitch and going with more blades. I use a 5-blade SS propeller that I bought from Ron Hill who is a custom prop builder who sells on ebay (http://stores.ebay.com/Ron-Hill-Propellers). As you can see, he sells both 4 and 5-blade props. I have found that the 5-blade helps with hole shot and also allows the boat to stay on plane at slower speeds, which is better for wakeboarding and tubing with small kids who don't want to go fast. With regard to pitch, you might want to even consider dropping to 19 to really make a difference with hole shot since you had to struggle so much to get up in the video (good job by the way). If you happen to live near Fishers, IN (Indianapolis) I will let you borrow an extra 5-blade Ron Hill prop that I have to test it. Lastly, the Mercury High Five prop is a more expensive alternative that you could consider too. Good luck.

 

[codertimt]

Re: Drop in pitch versus Smart Tabs

I appreciate the reply and the test prop offer. I'm down in Central AR, so unfortunately can't take you up on it. I went ahead and decided to go prop since I had the rpm to work with when loaded and otherwise don't have any complaints about how the boat planes/rides. Plus I just can't bear the thought of drilling into a brand new transom....

I went with a 21" Solas Amita 4 blade aluminum from here at iboats. I'm sure it's not going to be a high performer, but I hope it will give that extra bit of pull I'm looking for. I decided to stick with the 21" so I stay within or very close to my rpm range and not loose too much efficiency.

The rest of my plans for getting up easier include working out to gain some strength and loose some weight(and I need to for my health anyway as I've all by atrophied sitting in front of a computer all day for 10 years) and working on starting with my trailing foot out of the ski. I know I'm a much easier pull dragging a foot...I just never really got the hang of it though.

I guess I could always switch to a more appropriate ski for my weight as my old 69" H.O. VTI is really designed for my intermediate to advanced recreational skiing 200lb self of 15 years ago...but I'm not ready to switch to a "big boy" ski yet...

So we'll see how this works and go from there...

 

[TomP]

Re: Drop in pitch versus Smart Tabs

Good luck with the new prop. Once you try it, please let everyone know how it performed relative to your old prop.

With regard to getting up with one foot out of the ski, I have heard that that makes it easier or quicker, but I am not sure why. Do you? Seems like it would certainly put a lot more strain on the one leg doing all the work. Maybe it allows for less drag in the water?

 

[codertimt]

Re: Drop in pitch versus Smart Tabs

Good luck with the new prop. Once you try it, please let everyone know how it performed relative to your old prop.

With regard to getting up with one foot out of the ski, I have heard that that makes it easier or quicker, but I am not sure why. Do you? Seems like it would certainly put a lot more strain on the one leg doing all the work. Maybe it allows for less drag in the water?

It does have to do with the amount of drag. With both feet in, the natural tendency(at least for me) is to "dig in" with your rear leg. This allows for greater control and stability, but the more you lean back on the rear leg, the more you plow through the water. I called myself trying to put weight on the forward leg, but I know I'm probably leaning back too much...

With the rear leg trailing, you can't push down on the rear of the ski and it naturally tends to ride more parallel with the water and thus planes easier. You just have to get used to standing up with the one leg. Although I think once you get used to it you can push against the water with the trailing leg to help stand. The problem I have most of the time is getting pulled out the front as the posture I'm in is quite unnatural for me...

I will definitely check back in with a report from the new prop...and just writing that above has me thinking I need to examine my technique a bit more...

 

[xxturbowesxx]

Re: Drop in pitch versus Smart Tabs

i think you made the right choice i would have went stainless but you should be fine..

 

[tysonnathan]

Re: Drop in pitch versus Smart Tabs

When I get up on one ski I really have to tuck that back leg underneath. I try to put my heal on my rear... If I don't, I usually drag way too much and eventually get off balance.
I have always used a 19p prop and it has served me well. Comes out of the hole pretty well and tops at about 38-42 mph.