Leaning skiboat, normal?

[ErikBerghiller]

Hi!

I have an old skiboat from 1989 a US Marine Ski Challenger, its in good condition over all and my first real towboat. But there is one thing with the boat that annoys me, it is leaning towards the driverside while driving... a lot.

Some of my friends have old ski boats from different manufacturers and none of them leans as much as mine wich make the boat feel unstable.

 

Is this normal for older skiboats, if not what can i do to fix it?

 

Thanks!

 

 

[ALPJr]

Nice pic! Fairly common issue. Try adding a little weight in the observer side. Guy at our club uses a 40lb block in the rear corner of his 1989 Ski Nautique.

[Jody_Seal]

Pretty forward looking ski boat for 1989.

Not uncommon for ski boats to lean down to one side or another. Most of the time adding a bit of weight to the up side of the lean will address the situation. particularly if the boat is utilized with out an observer, running down on the driver side in that situation and left hand prop rotation will most surly cause the boat to be down to the driver side. If the boat rides driver heavy with a balanced load is not that uncommon either, again a little weight under the passenger seat may address that situation. If substantial weight is needed in what one would consider a balanced crew load say more then 50# then you might want to take a look at the trailing edges of the boat and check the Hook or rocker in the hull.

[ErikBerghiller]

Yes, most people dont believe that it´s soon 30 years old, it was very scratched on the outside so i wraped it with foil. Although the "miami vice" upholstery gives it away :)

I will try putting some weight under the passenger seat as a start, hope it helps.

Thanks for the tip.

 

 

 

 

 

[BraceMaker]

Is that with a spotter in the boat or with out?

 

[ErikBerghiller]

It leans less with a spotter but it´s not perfect...

[mwetskier]

its possible the lean could be caused by something other than just weight distribution. being from that vintage it could have wood hull stringers and some of those were known to rot or even come loose over time so you might want to get in under the floorboards and check the stringers. if they are wood you'll want to make sure they are sound and still firmly bonded to the inside of the hull.

[jjackkrash]

Older boats tend to have some quirks. I have a 2000 AM. Skier Volante that lists to port even when evenly loaded. I experimented with weight placement and rudder grinding and put about 120 lbs. in the port bow storage toward the rear of the bow. This placement helped the list, improved the wake a bit, and helped a bit with tracking. My advice is to play with some weight placement and do the best you can, but don't let it eat at you, unless you discover an actual structural problem.

[ErikBerghiller]

Interesting...

jjackkrash what did you use as weights? I´m thinking sandbags would work?

[jjackkrash]

I used standard barbell weights and made a mounting post so that I could pull them in and out easily and adjust the weight but so that they would not shift. I suspect training sandbags would work as well, just a little bulkier.

 

 

 

[wtrskior]

@ErikBerghiller jerry cans filled with sand work very well. You can have 3 or 4 different ones which weigh differently depending on the crew your rolling with.

[bishop8950]

My parents have a 1989 Centurion that came out of the mold wrong. It originally porpoised at speed which we corrected by adding hook in the metal plate that hangs off the transom on that boat. But it is also a bit twisted and leans heavily to the drivers side. We have enough weight on the passengers side to make it work but its not great. So as @Jody_Seal said checking out the hull might identify the cause if a bit of passenger weight doesn't level you out.

[Razorskier1]

Two thumbs up for shot bags. No stubbed toes

[A_B]

That is the beauty of the RH rotation props on Correct Crafts, they counteract the driver weight and run level. Most LH rotation boats lean to the driver-only side, especially with me as the driver! Hydrodynes and older Mastercrafts that I drove had me inching toward the middle all the time if we didn't have 100 pounds of weight on the left side under the passenger seat.

[skiinxs]

@A_B I have heard the "RH rotation argument on Nautiques" argument that it offsets the driver weight for years, but have always had trouble logically rationalizing in my head. I do agree that it should take less hook to make a RH rotation boat run level with only the driver, but to me, the reality is that all boats should be trimmed to run level with the full crew, regardless of rotation, so between RH and LH rotation, it only means more hook would be on the port or starboard side to level the boat. In the case about the Ski Challenger being a "leaner", I would pay attention to the post by @mwetskier and check for bad stringers, put a straight edge on the bottom to check for big hooks in places they don't belong, etc. If you find all of the above is ok and want to add some hook to trim the boat properly, start with a small bead of silicone sealer on the bottom at the transom on the driver's side. Once dry, run the boat to see exactly how the boat would run with the same amount of hook as the silicone. Once you find an amount of hook that works for you, duplicate the hook with the same amount of fiberglass replacing the silicone.

[A_B]

Think of the blades slapping the water as they turn to the right and that lifts the boat from the right side to the left..

We only have SN's in the stable of boats I drive now, so can only go by what I saw and felt from years ago.

[Tyler]

Going off @A_B comment, our SN 200 leans significantly to the spotter side even with only the driver in the boat. Not sure why it does this. We do have a Rack with 4 speakers on it and also a second battery and amp under the spotter seat. Perhaps that's the cause? We tried moving all the gear to the driver side, but it still leans. I would think the driver and gear would be enough to counter act the battery and amp... I don't know. None the less, our Nautique leans and we will be talking to the Pacific Nautique guys about it at the boat show at the end of January to see if they have any advice. I'll let you guys know what we find out...

[skiinxs]

@A_B I Totally understand that RH rotation torques the right side of the boat up (and stern to the right in forward), but what I am saying is that regardless of rotation, the hull needs to be trimmed to run level with a normal crew. Because of this I would expect more hook on the port side in RH rotation and more hook on the starboard side in LH rotation to attain the level running attitude. If a boat was trimmed to run level with only a driver and no spotter, RH rotation would require less (or no) hook, agreed. I just don't see that this is a valid argument for RH or LH rotation as an advantage. I have also found that props with higher cups tend to torque a little more i.e. a .150 cup 12.5x15.5 prop vs one with only .105 cup. Another interesting factoid I have observed is that Nautique's tend to be a little heavier on the driver side (I swear it is not just me driving:) Look at any 200 hanging by it's lifting rings. (probably due to steering cable, steering wheel helm, throttle box, gateway box, heater, etc.), but the factory does a great job of taking all that into consideration and building a boat that runs level with a normal crew.

[brody]

I had that boat for a long time, really liked it a lot. Didn't mean too much but was definitely noticeable

[skiinxs]

@Mark_Matis Absolutely agree. Prop torque changes depending on RPM. Also, it has been my experience that boats that have a lean corrected by adding weight react to different speeds with a greater change than boats that are more balanced with an even load. They seem to drop off plane a lot different.

[ErikBerghiller]

@skiinxs, I dont really understand what you mean by "hook", any pictures?

 

 

[DW]

@ErikBerghiller : to your last post, there is a thread on this site relative to a SN200 that has a picture of hook added to the trailing edge by adding some bondo, you might search using keywords like: hook, bondo, SN200, etc.). Hook is adding some material to somewhat mimic a 'ski jump' aimed downward that lifts that surface. Also, basically similar to a deployed airplane wing flap, but you only need a small amount to create the required lift.

 

On your vessel issue, I would also as noted really look in to any water absorption to key areas like the stringers, foam, etc. You might also weigh the boat (you can do it on trailer at a landscape business or any truck scale) to see if it is significantly over what is expected. You could also do each trailer wheel separately to see if there is an imbalance. If you know any car racers, they will most likely have a set of scales you could use. We have one of those on our lake just this year, have not had a chance to ski it yet but want to give it a try. Without really eyeing lean, when I got a quick ride in tourney seat, I don't recall that one leaning a lot, but don't use my comment as gospel, it was just a quick joyride.

[skiinxs]

Thanks @DW, I was trying to find an illustration and even tried to draw it with the results I expected (I am no artist!)

[DW]

@ ErikBerghiller: The dark color is the added bondo to create additional hook, in this case on Port side, you would want on other side:

https://us.v-cdn.net/5017617/uploads/editor/j9/agass2i8m7cm.jpg

[ErikBerghiller]

@DW okay now i understand, i´m planing on turning the boat upside down during this winter to paint the hull i think i will try to build my own hook then :)

 

[skiinxs]

@ErikBerghiller Don't forget my earlier post, you can experiment by putting small beads of silicone sealer at the back edge of the bottom to simulate the same depth of hook. You don't even need to contour it, the bead will simulate a like amount of fiberglass hook. You are going to want to know exactly how much hook and where to put it before you replicate in fiberglass. Do this while you can still run the boat. Try a little, run the boat, record the results, measure how much you put on. If you overdid it, remove and put on a smaller bead, or remove and add a larger bead if you need more. Trial and error is much easier with the silicone than with fiberglass!

[DW]

@ErikBerghiller : another option as a test method is to use the plastic bondo spreaders and simply tape them on with shrinkwrap tape. That way you can experiment with various thickness' to get the amount you want.

 

Of course hearing the latest suggestions and reading you latest post, it will hinder your winter project unless you can trial it prior to turning hull over.

[jjackkrash]

I think I'd at least start with a sandbag near the rear of the port bow before I started redesigning the hull, considering how much I hate sanding and grinding fiberglass. But hey, winter projects are always fun. :smile:

[jjackkrash]

Also, what about trim tabs?

 

http://www.overtons.com/Boating-Marine/Performance/Trim-Tabs

[ErikBerghiller]

@jjackkrash trim tabs is a good idea, easier to adjust to...

I´ll go with the sandbags as a start and maybe i build my own trim tabs if it doesent help.

Thans for all the tips!

 

 

[jetpilotg4]

Take up wake surfing