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Call me stupid....but I am new at this....what is the HDS? Hydronic dampening system. Fancy words for building a box around the point where the shaft goes through the hull and flooding it with water to absorb any shaft vibration. Works well though. A hotly debated point. If only Ruta could see this one. OK I take it back... I heard it works well. But, the person who told me was sitting on a bus bench on the shady side of Las Vegas with a gallon jug of Vin Rose between his legs... Honest.

Call me stupid....but I am new at this....what is the HDS? Hydronic dampening system. Fancy words for building a box around the point where the shaft goes through the hull and flooding it with water to absorb any shaft vibration. Works well though. A hotly debated point. If only Ruta could see this one.

Call me stupid....but I am new at this....what is the HDS? Hydronic dampening system. Fancy words for building a box around the point where the shaft goes through the hull and flooding it with water to absorb any shaft vibration. Works well though.

Your boat has the much touted-yet useless-Hydraponic Dampening System. If you lift up the floor in front of the rear seat, there is a rectangular piece of plexiglass with a bunch of screws in it. The shaft goes through there and that box fills with water. The problem is that the box (not just the cover) is not sealed to the hull properly or the sealant (Plexus) has failed. If you are the original owner it "should be" a warranty item at your dealer. What they do to fix it is remove the cover, get a grinder in there to remove excess sealant/debris. and re seal it with a special "epoxy". I had one done on a '99 LXI a few years ago. Good luck! Pat

I'm a little confused by "inspection area", and "water is 2" below area drained by the brass plug". ??? Regardless, yes.... you have a bunch of potential "entry" points into the hull where water could theoretically enter your boat. Most drive shafts have a slight leak..... around the "stuffing box". I suppose any of your water intake holes (you may have ballast pumps etc) could leak. The HDS could leak (Hydro Dampening System). I suppose also your exhaust outlest could leak.... Now that you are thoroughly afraid to leave you boat unattended in the water... I suggest you try the following. (I did, because I too was afraid of a submerged hull because mine sits at a dock for 2 ~ 3 weeks at a time.) I assumed my bilge pump had an automatic float valve that would turn itself on if the hull started to fill with water. I tested it. Filled the area under my motor with buckets of water. Buckets and buckets and buckets. Eventually, the auto bilge pump came on..... and drained all the water away. Not failsafe I guess.... but I felt much better. Depends on a good battery, the pump functions properly, no debris in the input fins of the pump.... but I felt a lot better.

Can't speak for CC, but actually MC does us a gelled liner in their bilge on the DDs. Difference being, the space between the hull and the liner is sealed with a polyester chemical bond and injected with closed cell foam that also increases sound dampening and strength. No room for water.

Hydrophonic. Andy, do you have a water temp sensor? If so, where is it located under the boat? If some of the hex heads from underneath would not tighten, it sounds like they are stripped. This could leave you in a bad spot with a mild underwater strike or just the pressure of turning. Also, a likely place for water intrusion. Instead of through-bolting, perhaps you should remove the fins, fill the holes, re-drill and reinstall. Do you have stress cracks in the gel coat?

^What is HDS? I can answer only because I asked the same question in a previous thread. I beleive it stands for Hydrolic (?) Dampening System. If I understand it, It basically is a box that holds water around the prop shaft to keep it from vibrating. If you search for it, someone posted a picture of one on another thread. Edit: I did the search for you. Here is the link to the thread with the picture. It also happens to be the thread where I asked the same question. HDS Leaking Thread

I was lucky enough to go to Orlando over the weekend for some business/fun. While there, I sauntered over to Drew Ross' place just outside of Disney for some sets in warm water. Drew has one of the first 2007 RLXi's out of the Tennessee plant. I skied three sets behind Drew's boat and three more behind Steve Carlson's promo 2007 RLXi. Mucho thanks to Drew and Steve for showing me a great time. Top notch guys that represent Malibu very well. (If anyone is looking for some instruction, I highly recommend Drew. Fantastic guy and a blast to be around--as is Steve.) Some thoughts... Slalom wake: I'm pretty lame in the course--still struggling at 15 off/34mph. I only skied at 15 off starting at 28mph running through 34mph. Honestly, I didn't think there was a noticeable difference between the new RLXi and the RLXi's I regularly ski behind here in Denver--2003, 2005, and 2006 RLXi. I suppose an argument could be made that the new wake is better, but I don't see it and did not feel it. Remember, I'm limited to 15 off. My buddy skied at 22 off and said the wake was very similar to his 2005 RLXi. I watched Steve Carlson ski at 36 mph from 28 off to 38 off. The wake looks non-existent at those speeds and line lenghts. Drew Ross told me he thinks the wake is better at 36 mph. Wouldn't surprise me based upon what I saw. Regardless, I don't agree with the marketing hype that the wake is 30% better. Reminds me of when CC came out with the TSC2 hull. They claimed a 25% improvement over the TSC1 hull/wake. I think we can all agree that the wakes behind those two boats are virtually identical. Sum: At least from my perspective, there's not a net gain here. We'll have to wait for a skier that can start out at 15 off and at least get through 32 off. Edwin and skisix, you game for a trip down to Florida? Pull: I enjoyed skiing behind this boat. Very consistent and soft pull--which I like. I had plenty of time at the ball and didn't feel as though I was getting pulled over at the waste. Things felt nice and slow while skiing with Drew Ross. And, you have to expect his boat was dialed in. By the way, did I say that Drew really likes the new boat? Same with Steve Carlson. Driving impressions. I didn't get to drive Drew Ross' boat. But riding with him was a real pleasure. At each end of the lake, when setting the skier, he would induce "oversteer" or a bat turn with the boat. When I drove Steve's boat, I understood why. This boat is very agile and athletic. With a flip of the wrist, you could bring or slide the back end around. Every time Drew did that he would grin and say "can't do that in a Nautique". I was only able to drive the boat for one set, and pulled my buddy--the probable buyer of Steve's boat. He's like me, a 15 off skier and doesn't put alot of load on the boat. I had no problems keeping the boat nice and straight--even at the end of the day when we were having some wind. The new bu feels very responsive, nimble and light. Feels like it rides more on top of the water than the previous RLXi. Everyone I spoke to that drove the boat had the same comment. No one was complaining--including a rated tournament driver who is also a long time MC promo guy who really liked the way the boat drove. When Steve Carlson skied, his wife drove and she had no problems driving a straight line even at 35 and 38 off. The hole shot is fine--at least at sea level. In fact, my friend about pulled my arms out when he pulled me--driving the new bu for the first time. The boat gets up to speed and settles down well before the the 55 meter gates--at 34 and 36 mph. Even at Drew's place which has a short set up, the new Response had no problems getting up to speed and settling down nicely. Everyone was scratching their heads at how the new boat didn't pass all the AWSA acceleration tests with flying colors. Looks: No problem with how the new boat looks IMHO. But that's very subjective. One of Steve's buddies was there with his 2006 RLXi. I must say, both boats sitting in the water next to each other is a site. The nod, though, has to go to the previous model Bu. That's just one dang sexy boat. Interior design: Superb. Makes my 196 look very very pedestrian. I have to say that I agree with Drew, bu's designers are very creative and innovative. My only suggestion would be for Bu to integrate the throttle control box behind the gunwale like CC and MC do. The Morse box looks cheap and sticks out like a sore thumb in such a innovative looking boat interior. Fit and Finish: No complaints here. Carpet and vinyl and gelcoat are top notch. Boat was very comfy to set in--even with four adults and three small kids and all the gear. Noise: Steve's boat had all the sound dampening stuff. Very quiet--Nautique like but with a throaty yet more refined growl from the engine exhaust. Windshield. I'll be honest. I thought the windshield sucked. It looks and feels cheap. Heck, Drew didn't even had a mirror as Malibu hasn't given him one yet. I couldn't get to the bottom of why--whether they had to make a special mirror or were just backordered. Steve's boat had one. The windshield feels like it will break if put any pressure on it at all. Not solidly mounted like skisix's windshield or other Bu's I've been in. The glass also feels like its a lighter gauge. Hopefully, Malibu will get this sorted out. That's about all I can think of. It's getting late and I'm still on eastern time. I'll post more tomorrow if I think of anything else. Overall, I could see myself owning one of the new bu's. But at the same time, I wouldn't flinch at owning at pre-07 either.

I fill it up as much as I can but I don't feel like it's completly full. The bag tries to take the shape of the area it's in but with the bag not fitting the area well it doesn't fill completly because it's longer than the locker. The 750 lber's are 20"X20"X50", even bigger than the one I'm using. You'll probably have to cut the carpeted wall in the front of the locker that the dampening shock is attached to for the sack to go under it to fill completly. Just go ahead and do it. There are many more people besides me on here that would love to see it work. Your going to get the 750's either way aren't you?

If you have a direct drive boat, you have a HDS (hydronic (?) dampening system). It is basically a box that fills with water around the shaft and it supposedly dampens shaft vibration. Seems to be more of a problem than a solution. Dave Thanks Dave, I can see why they don't go into this brilliant solution in the owners manual Others have called it the Hydronic drip system.... Yes you have it on your I-ride.

If you have a direct drive boat, you have a HDS (hydronic (?) dampening system). It is basically a box that fills with water around the shaft and it supposedly dampens shaft vibration. Seems to be more of a problem than a solution. Dave Thanks Dave, I can see why they don't go into this brilliant solution in the owners manual

If you have a direct drive boat, you have a HDS (hydronic (?) dampening system). It is basically a box that fills with water around the shaft and it supposedly dampens shaft vibration. Seems to be more of a problem than a solution. Dave

I did almost the same thing last year. I hit a tree submerged. Missed the prop but hit the rudder because I was turning. From the outside you couldn't see anything. Not even a stress crack. But it busted the floor loose from the upper liner. Which basically is the hydrophonic whatchamacallit box. I took on water faster than the bilge pump could pump it out. The water pressure while running was pushing the liner up. I don't remember exactly what it cost, but it was over $2k. SkiSafe took care of it less the deductable no questions asked. What sucked was I have a $1k deductable.

I'll also bite my lip here... FIBECs is..... agh.... biting lip...... M3, Sometimes taking the high road can hurt so, so bad. Just imagine if the Bu's didn't have all the sound dampening technology. (Wow! the DDs would be loud) Joe

Why is everyone using the foil faced foam? From Mcmaster's site it looks like the skinned version actual has better sound dampening characteristics. I know my old MC 190 had an open faced foam on the inside of the motor cover and it was fairly quiet and it didn't present any other maintenance problems. Any thoughts?

Jonathan, it's Hydrophonic. (phono having to do with sound; hydroponic having to do with growing plants in water) On a six year old boat, an HDS problem would probably be more extensive than what the OP describes. BICBW

Alright!! The 'Bu Crew's first mention of the dreaded HDS! My guess is that it may be the Hydroponic dampening system (HDS)?... aka that little box near the shaft packing... I have seen where direct drives have actually had the Plexus holding the layers of the HDS together, seperate, allowing water to seep through the layers of glass and into the bilge... If it is not the Shaft packing, perfect pass paddle wheel or other intake fittings on the hull, then definitely have the HDS checked out. JZ EDIT: did not want to worry you but this is something to keep in mind... hopefully its as easy as tightening the shaft packing...