Left tilting boat!

[robertsn]

Hello,
I have just recently purchased a 1989 Wellcraft 170 Classic. The boat is in good shape and has the MerCruser 3.0 i/O.

I have only had it a few days, but have been concerned with how unstable the boat feels in the water. With only my wife and myself in the boat it lists to the left fairly severely. We had a small tolling motor installed up front with the battery mounted in the left front storage compartment. I have already adjusted the small fin located above the prop and this helped some with the steering pulling to one side, but even after playing with the trim levels it still lists slightly to the left even with both of us sitting on the right side of the boat. The other odd thing is that at 10-15 MPH it seems fine, and then when it gets up to plane more it starts the severe tilting and we have to back down the speed.

This does not seem normal. The boat is about 1950 lbs and seems large enough to deal with a slight unballance weight. Does anyone have any information or advice?

I have read so far that weight distribution, water logged interior, and broken plane fin might be potential problems from the forums. Is it likely that one of these issues is the problem. I have also heard mention of smart tabs? Can someone explain what those are?
Thanks!

 

[TNT]

Re: Left tilting boat!

You can find info on SMART TABS here: http://www.nauticusinc.com/smart_tabs.htm

and, here is a video. Good luck with your issue.
http://www.nauticusinc.com/videos/Performance.wmv

 

[Maclin]

Re: Left tilting boat!

Does your boat have an add on fin bolted to the drive?

 

[robertsn]

Re: Left tilting boat!

Hi Maclin,
Yes it does. After I posted I did some reading on the dolphin fin type hydrafoils and saw that some people had problems with them causing instability. Since I am living in monsoon like Oklahoma right now I was not able to go look and see if the fin was damaged or warped in any way last night, but I started thinking that this might be a possible solution. Would you suggest taking it off and seeing how the boat handles?

 

[robertsn]

Re: Left tilting boat!

Thanks for the links TNT.
N

 

[snlgraham]

Re: Left tilting boat!

my boat listed slightly to the right. since I replaced the floor already I knew that it was not water logged. It is a 16ft trihull with 140 mercruiser I/O. when the kids left the fishfinder on(no it is not switched) the battery went dead. I removed the battery to charge it. when i came back to the dock the next day I noticed that it was not listing any more. it was perfectly level. It was the weight of the batery that made the difference. In a boat this small that 30 or more pounds did it. there is a swim deck on the back that is just above the water line, so any little bit of leanage(is that a word) was noticable. Also, that anode skeg fin thing on my outdrive was not straight and that made it feel unstable.
good luck

 

[Maclin]

Re: Left tilting boat!

I would remove the fin if it is simple enough, and see how it reacts. Those fins cause lift at the middle of the hull only which is the worst place for stability, like trying to balance a V on a pole. So if the boat tends to want to list one way anyway the fin could sure be making it worse.

 

[valkyr]

Re: Left tilting boat!

Hello,
I have just recently purchased a 1989 Wellcraft 170 Classic. The boat is in good shape and has the MerCruser 3.0 i/O.

I have only had it a few days, but have been concerned with how unstable the boat feels in the water. With only my wife and myself in the boat it lists to the left fairly severely. We had a small tolling motor installed up front with the battery mounted in the left front storage compartment. I have already adjusted the small fin located above the prop and this helped some with the steering pulling to one side, but even after playing with the trim levels it still lists slightly to the left even with both of us sitting on the right side of the boat. The other odd thing is that at 10-15 MPH it seems fine, and then when it gets up to plane more it starts the severe tilting and we have to back down the speed.

This does not seem normal. The boat is about 1950 lbs and seems large enough to deal with a slight unballance weight. Does anyone have any information or advice?

I have read so far that weight distribution, water logged interior, and broken plane fin might be potential problems from the forums. Is it likely that one of these issues is the problem. I have also heard mention of smart tabs? Can someone explain what those are?
Thanks!

Thats easy.....Too many democrats on board!

 

[88wellcraft]

Re: Left tilting boat!

I'm sure many people here would agree....take the fin off

 

[Jdeagro]

Re: Left tilting boat!

A port side list most often indicates a torque list. The prop rotates clockwise and the boat wants to unwind (counter clockwise). This is exagerated by agressive SS prop, four and five bladed props, too much negative trim, and hydrofoils. The agressive props create more resistance and more torque. The neg trim and hydrofoils provide too much stern lift (bow down) at crusing and top speeds which makes the boat ride on the keel which causes a sensitivity to side to side balance and torque. Like a teeter totter. Running with too much stern lift (bow down) also causes bow steering, a reduction in speed, and excessive leaning in turns.

Take the hydrofoil off and see what happens. Trim the motor out a bit as well.

Probable results:

The boat will be slower to plane. The bow rise will be extra high. The minimum on plane speed will move up to about 22 MPH. and porpoising will begin.

 

[robertsn]

Re: Left tilting boat!

Ah that really makes a lot of sense. It also fits with the feel of the tilt when the boat gets up on plane. I will remove the fin and try it out asap. If it keeps raining here I will need the boat to travel to work.....

Thanks for the explanation!

 

[rndn]

Re: Left tilting boat!

I wish I knew about this site years ago. You guys are really a great source of information.

 

[bushman10]

Re: Left tilting boat!

A port side list most often indicates a torque list. The prop rotates clockwise and the boat wants to unwind (counter clockwise). This is exagerated by agressive SS prop, four and five bladed props, too much negative trim, and hydrofoils. The agressive props create more resistance and more torque. The neg trim and hydrofoils provide too much stern lift (bow down) at crusing and top speeds which makes the boat ride on the keel which causes a sensitivity to side to side balance and torque. Like a teeter totter. Running with too much stern lift (bow down) also causes bow steering, a reduction in speed, and excessive leaning in turns.

Take the hydrofoil off and see what happens. Trim the motor out a bit as well.

Probable results:

The boat will be slower to plane. The bow rise will be extra high. The minimum on plane speed will move up to about 22 MPH. and porpoising will begin.

My new Larson 208 LXI with 5.0 MPI and Bravo 3 drive also lists (leans) to one side. It leans to the starboard side and I was wondering if it is due to the thrust from the Bravo 3 drive? You say thrust causes port side list?? It is about a 10 degree list at cruising speed and even when planed and trimmed up? It is driving my crazy as it is a brand new boat and I don't feel I should have to put trim tabs on a new boat as if this was a characteristic of this boat then Larson maybe should be installing trim tabs as a standard feature. There is no adjustment keel on this leg because the Bravo 3 props have only minimum clearance. I've e-mailed Larson Rep. with my concern and now awaiting there reply. Has anyone out there have this same problem with their Larson???

 

[QC]

Re: Left tilting boat!

bushman,

You've got different issues . . . start your own thread and you will get a better response.

 

[180shabah]

Re: Left tilting boat!

Hey robertsn,

One more thing to look at is your hull. It is now 18 years old and may no longer be fair.

For best performance it should be straight and flat(from the transom forward) for the first 4 feet or so. I have no intention of being the voice of gloom and doom, it is just one more possibility, and checking it is free.

 

[robertsn]

Re: Left tilting boat!

Ah, so the weather finally cleared today for a few hours and I was able to unbolt the hydrafoil and head to the lake. What a tremendous difference. Only a very slight lean to the left at top speed. That really did the trick. Even got my wife to drive and relax enough to ski a bit. After seeing how the boat handles without the foil I am really not sure why it was ever installed.

Thank you all for the problem solving and great advice. I now look forward to a great summer boating.
Take care,
robertsn

 

[180shabah]

Re: Left tilting boat!

Have fun!!!!

 

[Coors]

Re: Left tilting boat!

whale tails are only for wake-boarding
,and if you don;t have a 600 watt stereo spitting out crap; then the tail won't work.

 

[Gary H NC]

Re: Left tilting boat!

Now consider a set of Smart Tabs,it will cure the list and plane much better and stay on plane at slower speeds.Best investment you could make for a very reasonable price..

 

[studlymandingo]

Bought into the hype

Bought into the hype

After seeing how the boat handles without the foil I am really not sure why it was ever installed.

The previous owner read the advertisement and thought it would be a good idea.​