2004 ProStar 197 TT Hull Tuning - if a radical solution worked it would be cheaper than trading up.

[swbca]

I have had many experience skiers confirm that the ProStar EVO hull has a much larger 30/32mph slalom wake than some earlier ProStars and all later ProStars. I made the mistake of buying this boat assuming that Master Craft was making boats with a better slalom wake from one hull generation to the next. I had double knee surgery from my much earlier Correct Craft and this ProStar wake is worse than my old Correct Craft. Trading up isn't an option.

 

What would custom made wide trim tabs do ? It would extend the trailing running surface and maybe the adjustability would be useful. If the trailing edge Hook on the TT model is a turbulence complication, it could be removed.

 

Extending the rear running surface might have unexpected handling and wake-shape consequences, but warnings about that are just speculation unless someone has tried something similar or is a hull design engineer.

 

Below- You can see "hook" and it shows the trailing running surface is about 5" shorter than the hull.

My Grandaughter loves the ProStar wake.

 

 

 

 

[BraceMaker]

Been people on teamtalk over the years about these hulls mostly about adding hook to the earlier ones for the same complaints so its not necessarily that the hook made the hull worse for 30/32. So I wouldn't do anything destructive to the hull. Start with propping and put the boat on a diet.

 

[swbca]

@BraceMaker I wasn't thinking the hook caused the current wake problem, but if anything was done to extend the bottom plane of the hull, the hook would be pointless drag and create turbulence that would impact purpose of the foils.

 

Conceptually, I would like to test a wide set of foils flush with the bottom that generated about 400 pounds of lift = getting 2 big guys out of the back seat

at 32 mph. I don't know if that could be done without the foils having a greater planing angle than the hull, but an engineer could make some assumptions about the back-to- front hull planing angle and figure something out.

 

I have no hesitancy about removing the hook if there was an associated solution. As it is, this boat is useless as a practice boat for me and I am not going to trade up. I am currently using it for free skiing at 39 off where there is no wake . . . that doesn't mean I'm pretending to be a 39 off skier, except maybe on the green "training balls".

 

What about propping and a diet ? . . . please elaborate

[ScottScott]

I'm guessing that you may get better results from adding weight to various locations. 1st, making sure balanced left/right (which will change depending on passengers,) some moveable sand bags or other weights is good. Trying some weight in the bow is also worthwhile.

 

I skied behind a 2011 or 2012 and was surprised how good that wake was at 32mph/22off. I was told that was the last year before they went to ilmore. Not that ilmore is bad, but the weight distribution with a different weight ilmore didn't work out as well.... (just an example to the significance of good weight distribution.)

[skiinxs]

I would start with moving weight around as mentioned above. If that doesn't help I would add hook not take hook away. You can simulate the effect by running a small bead of silicone at the area of the hook which will increase the hook. Believe it or not after drying it will stay on while you run the boat and simulate what the boat would do with additional hook. Once you find the amount that you are happy with you can duplicate the amount with fiberglass.

 

[MISkier]

Get all the unnecessary weight out of the back. Don’t put anything in the trunk. Replace the platform with something more lightweight (carbon fiber?). Relocate the gas tank to the front (see @MNshortliner project on his Malibu) and see if you can remove portions of the trunk and/or replace the lids with lighter versions. If you have a tower, remove it.

 

Test different props for their effect on the wake (there will be an effect) and pick one that minimizes your issues.

 

As mentioned before, a little weight in the nose can help the wake, but be aware of the effect on the nose going into waves when the boat is not on plane.

[LoopSki]

If my failing memory recalls, didnt @eleeski do some experimental changes to a 197?

[MISkier]

Regarding the carbon fiber platform suggestion, I believe @DW has done this and could have some info on the weight reduction and overall project details.

[MISkier]

@LoopSki, if he did, it was probably to make the Trick wake bigger. He likes the 197 wake for that.

[BraceMaker]

Propping is straight forwards some hulls like 3 blades some like 4. People claim 4 blades have a lifting effect not sure I buy it fully. But I feel like the problem with 197 wakes is that they have a trough with a single well formed wakes. 196s always seem to have had a wider trough area with 3 smaller wakes inside.

 

With trim tabs and such my experience has been whatever you displace down eventually comes back up. Surprised we dont have more of a textured trim tab product like the groomer on a snow cat. I would think that could help.

 

 

[swbca]

Adding to the hook . . I have wondered if doing more with the hook is the right answer. I am sure a larger foil (2 wide trim tabs) that are flush extension of the boat bottom would create less drag and provide more lift if sized correctly. But if that could be done with deeper and probably longer (front/back) hook that would be simpler to do.

 

Weight distribution

I am looking for a solution or combination changes that reach the 300-400 pound unweighting goal at back of the boat. Moving the fuel tank would be the biggest single thing, when the tank if full, but almost nothing as it approaches empty.

 

I currently have 200 pounds on the left bench seat in the 197 bow. Its not all the way to left because the bench doesn't permit that. It balances my driver and puts some weight in the front. It did not make a wake difference that I noticed.

 

At some point adding weight to the front causes the boat to dig a bigger hole through the lake and not decrease the wake.

 

Engineered Trim Tabs

If concept of big trim tabs shaped to be flush with the boat bottom would do the job, that seams like the easiest way to get the biggest change. There should be a big gap between the foils directly behind the prop to avoid vibration from vertical prop wash.

 

I have no concern about keeping it stock for resale. Does anyone have any specific functional concerns about this approach?

[ScottScott]

Trim tabs or hook could help, but as with the weight in the front....extra lift at the back would cause bow down also, but hopefully not as deep in the water overall.

[jedgell]

I know you said changing boats isn’t an option but why not? You can spend countless hours and potentially making some dangerous changes for a minuscule improvement? There are 196’s, Malibu’s, or Carbon Pros out there that will solve everything and be stock. I know it’s a hassle buying and selling boats but for your situation well worth it.

[UWSkier]

I'm surprised you like that hull at 39 off. I've tried that once free skiing behind an 08 and the trough was more disruptive than the wake at 32 off by a good margin.

 

As others have said, diet will help the most. Keep fuel load below 1/3. Use the trunk only for light things like towels, throwable cushion, spare buoys, etc. Get a couple of 50lb weight bags and experiment with moving them around.

 

And if you try all that and still don't like it, look for a malibu response LXI from around that same model year. They have great wakes and can usually be had for reasonable prices in non pandemic market.

 

Personally though, I think you'll learn to like that MC. People dog that hull a lot but I never thought it was nearly as bad as it was made out to be.

 

 

[dbutcher]

Sell it to a wakeboarder and buy a slalom boat, older if necessary. If there were a safe fix for that hull, it seems like someone would have done it in the last 17 years. Alternatively, buy a newer boat if possible. I know you want Zero Off.

[swbca]

@BraceMaker You said "With trim tabs and such my experience has been whatever you displace down eventually comes back up"

 

That sounds right if you have a small trim surface at a steep angle, but a large surface that's a straight extension of the hull should just make the boat "bigger" and ride higher. Doesn't that sound right ?

[chrislandy]

My understanding is, adding more hull hook will reduce the wake as it adds more lift to the rear of the hull. It's the principle behind "Zipwake" blade style trim tabs.

 

I'd start by adding a few 5gal water containers in the bow as you can move them around and it's pretty much free, works well with the kids at slower slalom speeds in my 205

[eleeski]

I played with my 197 - mostly trying to "improve" the slalom wake so they wouldn't overhaul the hull (with its wonderful trick wake). Interesting results. But they changed anyhow.

 

I added a plate/foil to make the slower speed wake VERY nice. But at 34 and 36 it was horrible. I added a bubbler to make the high speed wakes softer (magic!) but it didn't help the slow speed wakes. We experimented with props for minor benefit.

 

It is possible to improve the wakes. You will need to adjust for different speeds and disciplines. The mods were too complex and the boat is too good stock (the reputation is undeserved) so I'm still skiing mine stock.

 

An adjustable trim tab might be the ticket for both surfing and slalom. Just experiment and keep track of the right settings for what you are doing. The 197 is a GREAT boat. Enjoy it

 

Eric

[DavidN]

@swbca

Did you watch yesterday’s King of Darkness webcast?

See young Rocketman ski at 28-30mph behind the new ProStar that supposedly has “THE best slow speed wake”?

He was really fighting the wakes and got airborne every wake crossing, was painful to watch and I felt really bad for him.

I don’t know if it’s really worth trying to shape your hull (and possibly ruin it in the process) just to get behind one of the newer boats with that kind of wake at your next tournament anyway.

 

[thager]

Well, there's always tubing...

[UWSkier]

Could try outboard otherwise. Some of those old ski outboards have tiny wakes

[skimtb]

You could try to trade (buy/sell) to a nautique or mailbu of similar age. Likely better to lose a few bucks there then to spend a lot more messing with current boat.

[SkiBadger]

@swbca, I have a 2002 Prostar 190, purchased in '05. I agree with all previous statements about getting the weight out. Empty the trunk, remove rear seat. If I recall, the 197 weighed about 200LB more than the 190. Due to the front seating?

 

The prior owner had the hook added to gel coat by local dealer, and the wings cut off the rudder. I skied behind a friend's 2001 PS190 on my lake without the hull hook, but with the winged rudder. Noticeably softer wake at 32 IMO. So, I installed the winged rudder and it did improve the wake. You may want to try the winger rudder. I did see one ski-it-again. Easy to install without any modifications. BTW, I add 100LB on left side in the bow for balance.

[DW]

@swbca - what is your willingness to alter your boat as that is the limiter on the level of improvement attainable. If not much, don't bother to read on. I have massaged (probably a bit of an understatement) a mid '90's boat with excellent results. Hull modifications and weight reduction / balancing produce great results. I pulled out 475 lbs by making carbon fiber / foam core parts, swapping all the cast iron engine parts for aluminum, removing any unneeded part (there are a lot of them) plus a couple of significant hull modifications. Once you drill that first hole, the rest are a lot easier:-) The key on weight reduction is prioritization of the transom as noted by many here as you want to get the transom to sit as high as possible. I gutted that area. The side benefit is improved tracking via moving CG forward. Leveling the running list of the boat is also very helpful so consider where things like batteries, and any fixed item is placed as that is free weight you don't have to compensate for when moved to a more ideal position.

This is clearly not a type of project for many, although I will say it is pretty rewarding if you like that type of thing. Another benefit is a light boat is a lot of fun to drive.

You noted trim tabs could reduce drag, be careful there as boat drag is highly predicated on running surface area. That is one reason the latest gen larger, heavier ski boats require significantly more power to move. Trim tabs are very sensitive to porpoising also. Hook is actually a reasonably efficient way of pitch trimming a ski boat, very much like a gurney flap on a race car wing.

[swbca]

@DW @BraceMaker I was consider trying something that is easy to test. Taking a 1/16 x 3 x about 36" piece of stainless steel and applying it to the hook on my boat. On a trial basis the connection could be less than perfect, but if it worked the leading edge of the SS Plate could be beveled so it blended into the straight hull surface in front of the hook.

 

I would rather try some trim tabs but its complicated because the rear edge of the boat

has curves so it would take a fairly narrow tab for the piano hinge to be uniform & parallel to the bottom edge of the boat. Plus its a lot of effort without knowing if it helps. I wouldn't install the hydraulic actuator until I learned if it work by using some type of turn-buckle type link.

 

Its easy to suggest swapping boats but that is not a mid-summer undertaking when running a business and keeping the family happy.

 

I can imagine all sorts of result artifacts - but this is an easy test.

[skiinxs]

As I mentioned above, a couple beads of silicone is a super easy way to see the effects of additional hook.

[SkiBadger]

 

https://www.ski-it-again.com/php/skiitagain.php?endless=summer&topic=Search&category=Parts_Boat&postid=54839

 

You may want to try the winged rudder before drilling into your hull.

 

 

 

 

[swbca]

@skiinxs I saw your post but would be interested to learn if you have experimented with hook changes personally to know if you can get a significant change in wake size ? Foils usually have a clean edge to create lift by directing flow . . I had a hard time seeing a round bead directing water off the edge affectively. I would appreciating hearing what you learned. Thanks

[DW]

@swbca - research SSP (Scarpa Suppression Plate) which is a Malibu item. Several feedback comments on how they perform. Easy to test, yes, although it will numerous runs to optimize the incident angle so just be prepared for an extensive testing session.

[LeonL]

"Trading up isn't an option." If you consider your time worth anything, and possibly with no net improvement maybe you should consider that option.

[swbca]

@SkiBadger I have sent a message to the seller to get his assessment. The wings look like they would help. But this boat needs a lot of help. A person familiar with the 2004 PS 197 described the wake at 30mph . . its starts throwing a trick wake at 30mph. In 2003 they went to the Indmar engine which messed up the wake with balance and weight.

[SkiBadger]

@swbca - What engine is in your '04 PS197? 5.7L or 6.2L? Enclosed cooling?

Large engine with enclosed cooling will add a lot of weight.

[mlange]

I NEVER got OTF (mostly because I'm too much of a tail-rider) but the one time I did was because of the SSP on an RLXi. It made the wake a rock. Great for footing. Terrible for slalom.

 

Friends don't let friends slalom with the SSP.

[skimtb]

https://www.ski-it-again.com/php/skiitagain.php?endless=summer&topic=Search&category=Boat_3Event&postid=60301

 

As stated above it seems you have a nice 3 event boat and good for slalom at higher speeds. That boat isn’t known for great wake at low speeds and long lines.

If you could break even on this boat it would be interesting.

[UWSkier]

or if you want to keep the open bow, one of these. https://www.ski-it-again.com/php/skiitagain.php?endless=summer&topic=Search&category=Boat_3Event&postid=59938

[swbca]

@LeonL Your advise makes me think you have had some experience with people trying to improve this boat for 30-32 mph slalom without success. Do you know of anyone has tried trim tabs on this hull, or increasing the hook ? I don't want to repeat other failed efforts, but I haven't yet heard of any failed or successful efforts. Does your experience with ski boats make you think it can't be fixed ? Starting over in M9 I am looking to save this 2021 ski season. I have skies piling up around the house . . . no place for a second boat.

[swbca]

@Gloersen is this what you mean ? >>> Goldilocks effect refers to an infant's preference to attend to events that are neither too simple nor too complex according to their current representation of the world. This effect was observed in infants, who are less likely to look away from a visual sequence when the current event is moderately probable, as measured by an idealized learning model.

 

This persistence infant was always able to make a crappy new ski work by modifying it; tuning a crappy hull doesn't seam impossible. This boat skis great at 32mph / 39off. I'll just keep free-skiing until I replace it or fix it.

 

 

[MNshortliner]

It’s starting to sound like the easiest fix would be to just ski at 34 mph. Probably not the most ideal situation but if you want a good wake now, in the middle of the summer, it might be the only option.

[skiboyny]

The used boat market is really hot, seems like you would be able to sell at a great price and buy even an older model with a better slalom wake and not lift a finger. I know you said that's off the table but there will never be a better time to sell than right now!

[ReallyGottaSki]

Wow, the angle of attack on that wing looks huge

[teammalibu]

I put a wing like that on the rudder of my 88 Nautique back in the day!

Really improved the wake but the handling and top speed went to hell!

[swbca]

@MNshortliner Sking at 34 could be a long term solution that I haven't tried. I am pretty confident that 28 & 32off at 34mph would be my work zone. Skiing at 34 would be a good measure against where I left off in Men 3 skiing at 34mph for a decade or so. Just sized down to a 67" ION which should be OK at 34.

 

Thats an idea I can jump on today

[swbca]

@teammalibu I looked at the winged rudder on Ski-it-Again. I wondered about the handling affects. Plus the seller took it off of his boat . .

[LeonL]

@swbca No, I don't have experience or know of anyone who attempted to make significant improvements to said model of boat. Just going by my past life experience. I've tried to make things work when I just should have moved on to something that already works. See the @skiboyny post.

[MNshortliner]

You said you were free skiing at 39 off earlier? I have never had luck free skiing at anything shorter than 32 off and getting into a nice rhythm. It just doesn’t feel right and tons of slack after the apex for me. But that 32 off just feels like the sweet spot. You will have to find a happy medium with the wake at 34mph.

[ReallyGottaSki]

Yes, appears that flat plate would cause some lift, but moreso drag and just cavitate and make bubbles.

there are valid reasons propeller blades and foils are not just flat plates. shape, taper, chord, AoA, seem very important to a good design. seems it was rushed

[LoopSki]

Don’t try the scarpa plate. Its makes the wake really hard as stated earlier. I skied the

“ Bayou Boogies “ boat awhile back and it was a rough set.

[SkiBadger]

@swbca - from my experience, you will only notice a difference using the winged rudder at idle speed. The smaller profile rudder I found to be less responsive only while at idle speed. No other change in performance or handling that I've noticed. Again, it noticably improved the 32mph wake on my 2002 PS 190. Easy change.

 

Also there may be some value at looking at your prop. It would be interesting to hear from people who have more experience with this hull and prop types. 3 blade vs 4 blade and OJ vs ACME. I changed from the 4 blade OJ cast original to an OJ CNC'd 3 blade. I know some who are happy with the 3 blade ACME.

[swbca]

Skied behind a 2008 Correct Craft 196 yesterday. Nice soft wake compared to 2004 ProStar 197.

 

Tried it with the Hydrogate in Slalom and Tricks. The trick setting had a much harder wake. The owner says the gate drops the bow slightly but mostly the shape of the wake is changed. You could see some of the changes from the boat.

 

For those that have asked, I was just a spectator at the tournament last Saturday. I had only skied on the 67" ION two times and didn't want to look too foolish.

[MattP]

https://www.ski-it-again.com/php/skiitagain.php?endless=summer&topic=Search&category=Boat_3Event&postid=60222