Improve hole shot, Smart Tabs, prop?

[LSkiSki]

I purchased a boat last fall, 1998 Regal 1700 lsr with the 3.0L Merc and Alpha one. It is currently running WOT @5200 rpms with speed of 35? unconfirmed by GPS, waiting to borrow one. It currently has a 14.25 x 19p ss prop. The engine all checked out, compression was good across all four. Not sure about the weight of the boat. The boat does have a couple of big scratches on the hull, and the lower unit is banged up. The prop also has a small ding on each blade. Would this be enough to cause a problem? With 2 people and a light load, boat planes fine but top speed seems to be lacking. With 4 people and a heavier load, the boat really struggles to get on plane. The boat seems to be rather stern heavy. If one or two people are up in the bow, the boat planes ok, not the best, but when all are in the back, near impossible. I haven't tried skiing behind it yet, but would like to, and I have a feeling it will be hard to get up.

I was reading alot about the smart tabs, but I don't think they would work due to the contour of the transom. They would have to be placed pretty close to the lower unit. See attached pictures.

So, my questions are, would changing props to a 4 blade (3 currently) make an improvement? On the Nautics web site, there is an installation example that shows too far inboard on a contoured transom, and that would be the exact setup I would need. What is the problems with having the smart tabs too close to the lower unit, or is it just not effective that close.

I really like the boat and am looking to get better hole shot and quicker planing with a bigger load in the boat. Top speed isn't a real concern, just seems like it should be better with a 17 foot boat. The contoured/stepped hull is supposed to be a quicker design. Maybe the 3.0 is underpowered and I am going to be stuck with the way it is, but just thought I would pick the brains of all the knowledgable people I have read on this site.

Thanks in advance!

 

[Bart Sr.]

Re: Improve hole shot, Smart Tabs, prop?

You might have a spun hub on your prop.

My 16.5 ftr has a 3ltr/130 horse with the same size and pitch prop as yours and has no problem doing 45 with 4 adults @4700 rpm.My drive is a Yamaha.

 

[QC]

Re: Improve hole shot, Smart Tabs, prop?

I think your top speed is possibly right . . . Maybe a weight issue, and maybe slightly off in power, but 140 bhp is 140 bhp period. I also don't think a boat with a spun hub would go 35 MPH, but some here swear that a spun hub or a coupler has been the culprit before with their boats. I also don't believe your tach.

Confirm with GPS, and confirm with known good tach and start over. You can scribe a line between the inner and outer hub of your prop. Run it, if the lines don't match up when you're done, then Bart has nailed it . . .

 

[LSkiSki]

Re: Improve hole shot, Smart Tabs, prop?

How would I check for a spun hub? The prop is all one piece, no separate inner hub that I can tell. Mark or scribe a line, but where exactly? I thought a spun hub would barely move the boat, but I'd be willing to check. I will check the mph with a gps, but won't be able to get out until early next week. Busy summer, unfortuneately. Also, how would I check with a reliable tach? Not sure what to do there.

Does anybody add weight to the bow of the boat, sand bags or something. Cause when people are in front, it planes alright. Just seems like a bad idea to add more unecessary weight to the boat.

I need to buy a spare prop anyway. Probably go with aluminum because of price, but kinda wanted to wait to see if somehow I could get the smart tabs to work or not.

 

[LSkiSki]

Re: Improve hole shot, Smart Tabs, prop?

One more thing I thought of after the spun hub comments. The other day with 4 people, it struggled to get on plain like mentioned before. But, all of sudden the rpms were really high and i had to cut way back on the throttle. I had a hard time keeping on plane without over reving. It felt like something was holding me back. This is on the river and was fairly windy. After I stopped and started going again, everything was fine. So maybe just some weeds around the motor. Just thought I'd mention it as it could be related to spun prop, not sure.

 

[Bart Sr.]

Re: Improve hole shot, Smart Tabs, prop?

The weed thing is possible,even probable.Like QC said--scribe a line out from center and take a ride.If the line is in two places when you stop and look then you have a spun hub.

 

[QC]

Re: Improve hole shot, Smart Tabs, prop?

Weeds will definitely cause that . . . Not saying that's what it was, but I've had them choke my prop so it wouldn't go anywhere and there was and never has been anything wrong with my latest swetheart.