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HDS. Hydrophonic Dampening System?

Search "HDS leak". Maybe your Hydrophonic Dampening System is compromised.

Leaking Hydrophonic Dampening System.

I know some have had success doing it themselves. If you type in hydrophonic dampening in the "search" box above you'll find all kinds of folks with the same issue. If you have a dealer close by they are probably familiar with it also. Search link: https://www.themalibucrew.com/index.php?/search/&q=hydrophonic dampening Steve B.

When we surf our 99 RLX, the rubrail is definitely under water when the boat is listed. Maybe you have a void where the top deck and hull meet? Or if this is regular event without the Wedge, then you could have a leaking HDS - Hydrophonic Dampening System. If you are a first owner both would be covered under the mfg. warranty.

Do some searching here. It's a hydrophonic dampening box. The intent was to mitigate vibration frequencies from coming into the boat where the drive shaft penetrates the hull. On the impeller that @jayR mentioned, he's talking about the raw water impeller. That boat is open cooled so raw water is drawn from the lake via the raw water pump. In the raw water pump is an impeller that requires maintenance. The water goes from the raw water pump through the transmission cooler then into the engine circulating pump at which point the cooling system works much like an automotive cooling system less the traditional radiator and antifreeze. The circulation pump sends water through all the cooling jackets in the block and head and sends the water out through the exhuast. There's a wealth of information on this site. Searching is your best friend.

The boat is 100% fiberglass, including the stingers. There is the HDS - hydrophonic dampening system in the boat IIRC. I'd look for leaking.

Biggest possible "gotya!" is the HDS - Hydrophonic Dampening System. It works until it doesn't and then you take on water. Lots of water. But a rock solid boat otherwise.

Google HDS - hydrophonic dampening system

hydrophonic dampening system on dd's.

Hydrophonic Dampening System.

HDS = Hydrophonic Dampening System Lot's of threads about it if you do a search. Here is one

Hydrophonic Dampening System. It's on Direct Drives only. If you open the area behind the engine box between the mufflers (usually) you will see a box. When you are in the water, this box fills with water (hypdrophonic). It's stated purpose is to reduce vibration and noise (dampening). The purpose and existence of the box is open for much debate.

Not sure if you've checked this out - http://www.themalibu...ions/specs_main - there is some good info available for comparison of different Sunsetter models. If you click on 1999 you will see the Sunsetter LXi vs. the Sunsetter LX. The HDS is Malibu's lame hydrophonic dampening system that supposedly reduces vibration by having the shaft run through a water-filled box. They are prone to leaking - lots of info on the site if you search "HDS".

Or, at the least, checked the fluid level? The 'cavity' that you refer to is the Hydrophonic Dampening System (HDS). Is the sound you hear only in neutral, only in gear, only in reverse, or all of the above? Does your shaft packing drip? When and how much?

HDS stands for "Hydrophonic Dampening System" It is the "box" that is formed as part of the engine chassis system (fiberglass floor system: the entire black fiberglass portion of the boat that is the stringers and floor of the engine compartment) This entire system is glued into the hull of the boat. The idea of the HDS is that water fills the box through the prop shaft opening to "absorb energy generated by prop thrust vibration, creating comfortable, vibration-free boats." The HDS leak (if one occurs) is not a leak between the silicone sealed and screwed down lid (this would be real easy to fix) but rather a void in the adhesive, bonding the chassis system to the hull. If such a void develops, water will push its way from within the HDS box, between the hull and chassis, until it shows up inside the boat. The most common test to see if this is the source of a water leak, is to (with the boat out of water) disconnect the battery so the bilge pump does not run, put water in the boat (often suggested to a depth equal to the top of the HDS box). If water eventually drips out the shaft opening in the hull bottom, an HDS leak is assumed. I would think that the prop shaft seal shoul be tightened prio to the test, other wise, water passing thru the packing would give a false test for an HDS leak. If dripping water does suggest and HDS leak, I would remove the box lid and repeat the test to verify that the water was not simply coming through the stuffing box hardware or the lid itself. Repairs for true HDS leaks in the bonding vary. Malibu reccommend grinding the seam between the chassis and hull and adding more of the bonding adhesive used for the original bond. Others have installed shaft logs thus eliminating the water in the HDS system alltogether.

Are you asking seriously? If the search function did 3 letters, HDS would get you 150 threads. . . Hydrophonic Dampening System supposedly quiets the boat by surrounding the drive shaft with water. Supposedly is a (perhaps) stronger design than others use. Historically, if HDS is going to present a problem, it does so early in the boat's use. This occurs, as I understand it, due to the fiberglass not being laid up correctly in this area. If it presents a problem in later years, such as the OP, it's usually a result of hitting something. Pete, didn't you have this problem once upon a time, or was that someone else?

Hydrophonic Dampening System...Basically it is a box that allows water to surround the prop shaft and dampen vibration/noise. Malibu DDs have them. They are visible underneath the access hattch in the floor behind the motorbox. They have been know to leak in the past (leak into the boat). Someone used to have a video of the HDS in action..they replaced the top with clear plexiglass. It looks like and sounds like it is the HDS draining as it normally should. No worries. Nice looking ride by the way!

Your boat should not be taking on enough water in just two weeks to kill the battery. Hydrophonic Dampening System (or something like that). It's the box built into the floor of the bilge that the driveshaft exits through. There is great debate as to whether or not it actually does anything beyond cause headaches. The drip rate of the packing should have been checked when the dealer discovered and corrected the driveshaft coupling bolt issue. With the drive shaft vibrating as much as it would with only one bolt in it it had to have beat the snot out of the packing material in the shaft log. The packing material wears slowly over time requiring occasional tightening of the shaft log nuts. Eventually the material needs to be replaced but just to give you an idea, my 2000 (with ~500 hours on it) still has the OE packing material. The shaft log is the piece that seals the hole that the driveshaft goes through. Traditional shaft logs have the replacable material in them and typically have a drip rate of 1 drip every five to ten seconds. The dripless is a newer design and obviously by their name they don't drip but I have to think that a wobble/vibration like what you are talking about would have destroyed the entire unit. End result - you need to identify where the water is coming from. If it is coming from the shaft log (around the drive shaft) that's an easy fix, just tighten the nuts. Worse case...replace the packing material. If the HDS is leaking, that is definitely a more intricate repair and probably not a DIY.

That's basically what I was trying to get at, politely, when I said: If you're planning on sticking around awhile, be a good idea to chill. Hey, just out of curiosity, in your conversations with the engineers, did they happen to tell you the purpose of the HDS (hydrophonic dampening system) in the DDs? George at Malibu gave me the info, he didn't refer to it as such, but is it the same thing as the lining foam he referred to(the allegations of his that everyone is laughing at and not believing)? Thanks for the advice, fyi I have learned a lot from these posts from guys like you that keep it respectful, and I don't want to get kicked off or be responsible for closing the thread.

That's basically what I was trying to get at, politely, when I said: If you're planning on sticking around awhile, be a good idea to chill. Hey, just out of curiosity, in your conversations with the engineers, did they happen to tell you the purpose of the HDS (hydrophonic dampening system) in the DDs?

If I remember this correctly... HDS = Hydrophonic Dampening System. It's a box that fills with water that surrounds the prop shaft. Malibu used to use it as a marketing tool stating that it provided a smoother ride, etc... Doing a search on HDS will provide a bunch of hits. Below is just one of them. http://www.themalibucrew.com/forums/index....6496&hl=HDS When an HDS failure occurs it is generaly early in the life of a boat rather than 8 years later. The only reason I brought it up was because you stated it appeared to be coming in around the rudder, which the HDS box is just in front of, and it is a new boat to you, so you wouldn't know the history of the boat, etc... Mike

My thinking exactly. More than one person has spent $$$ fixing the darn thing. If nothing else, its peace of mind. What is HDS? Off the top of my head, I think it means hydrophonic dampening system. It's that box the shaft goes into just behind the engine. It is unique to Malibus. It was originally touted as a sound/vibration dampening device. I'm not sure if they even mention it anymore, but it is still part of every DD they build.

Personal opinion. It's not the tracking fins, it's not the lid of the Hydrophonic dampening box, but likely the internal seal of the box itself as mentioned above. Take it in to the dealer and have 'em fix it. Peter. ps - You'll need to have them glass over those holes for the fins that now are loose and re-tap them.

Sad to say, but I belive he is. Actually, I heard the same story earlier today only I heard the two guys are leaving their wives because they're in love with each other and that they're renaming the company Brokebackbu. That brings a whole new meaning to the SSP now doesn't it.... Not to mention "The Wedge" Hey you think the gay guys... oh wait we can't use that anymore can we? You think the homos.... er, sorry - you think the wealthy men will do away with the Hydrophonic Dampening System?