Why does that happen ?

[Sea Rider]

My boating Club is undergoing constant costly jet-ski sinking, was wondering why, any clues on the subject ?



Happy Boating

 

[racerone]

It is a known fact that some folks do not like the machines / behavior of the riders.----I refer to them as " bumble bees " as they seem to buzz around and make noise.------Oops , that machine looks just like one.-----

 

[GA_Boater]

Are they sinking at the dock or out on the water?

 

[Sea Rider]

Are they sinking at the dock or out on the water?

All when running at speed, there seems to have water intrusion somewhere ? The jet ski was towed 10 miles away making its return to the Club diving under water as a submarine. The crane was just releasing the flooded hull before sitting on its trailer. I'm in plain agreement with what Racerone posted...really hate those guys..

Happy Boating

 

[racerone]

So it sank while being towed ?------Recall 2 strokes using an engine driven bilge pump.----Not sure on 4 strokes.---Perhaps they need a battery powered bilge pump or a bigger bilge pump..

 

[Scott Danforth]

Jet skis being towed need to have the anchor point up high like 15 feet off the water (2nd floor of a houseboat or from the sundeck type thing) to keep them from becoming submarines (from the captain of a large yacht on lake Powell)

or the tossing around in the wake behind the boat causes them to roll and sink. usually when you notice the jet-ski is under water, you cut throttle on the boat doing the towing and the ski will pop up...... then you need to fire it up to clear out the bilge

the bilge pump on most jet skis is a siphon tube in the jet plumbing.... motor not running...... no bilge pump unless the owner fit an electric bilge pump.

 

[Sea Rider]

The flooding and sinking happened when cruising at speed far away from other boats on flat calm water cond as early in the morning. Someone who knows about this issue said that was due to water intrusion through the inner prop shaft seal and motor. BTW, those toys have been mofified for racing, runs at a much higher wot rpm than the recerational ones that could account for that to happen. So far this year 5 of them went scuba diving without driver. Al least don't fully sink, can see just the exposed bow while floats at a vertical position.

Happy Boating

 

[QBhoy]

That particular model of Seadoo, along with some others have a known issue with carbon seals failing. The internet is full of accounts of them sinking due to this. No good at all

 

[Sea Rider]

That particular model of Seadoo, along with some others have a known issue with carbon seals failing. The internet is full of accounts of them sinking due to this. No good at all

Good point, that's what the frustated owners told me. Other brands at my Club have developed same issue but at a much less occurrence than Seadoo has. Wouldn't accept a jet ski even if it's for free, are boaring machines, stresses your arms and shoulders and only good for 2. Anything that floats powered with an outboard all the way..

Happy Boating

 

[JimS123]

We used to call them "waterbugs". Absolutely hated them. Then on a trip to Hawaii we rented one just on a whim, and liked it. That Summer my son bought one and that was it. We are now on our 3rd 'ski and absolutely love it. We use it just as much as our other boats. Even take it on vacation cause its so easy to tow and we can go anywhere in it.

The waterbugs were a pain because they dominated the areas around docks, and chased passing boats. The models of today are smooth, comfortable and fuel efficient. Our cruiser seat is quite comfortable. With cruise control and no wake mode, its a joy to ride. We don't jump wakes, we cruise all over the lake.

Now, to the question...I find it hard to believe that a seal could be the problem. The automatic bilge pumpS can take care of a lot of water intrusion. The faster you go, the faster they pump.

What they can't handle is if a cooling water hose comes off. Then the faster you go, the faster you sink. Another option is going too fast and taking a nosedive.

However, in either case it should not be a problem troubleshooting. If it took a dive the driver knows. If its a hose (or a seal) the defect should be visible. If not, put it back in the water and check every 5 minutes.

When the hull takes on water, you know it, even a little I have to believe that the drivers knew they were sinking. If so, they should have taken quick action. That would lead me to believe that it was catastrophic, not a little leak.

 

[Scott Danforth]

BTW, those toys have been mofified for racing, runs at a much higher wot rpm than the recerational ones that could account for that to happen.

the source of the issue is here.

how were they modified....... and with a higher RPM, there is higher pressure on the hoses and pluming for the cooling circuits..... so double clamps and hose glue are required.

 

[Sea Rider]

Whichever the issue was, could be a blown hose from where it used to work and water entering fast on hull. These guys aside from raising also comes to a stop while floating with motor off, which could increment the flooding much faster. The modification is mostly done to the electronics so the motor revs much higher than the standard models.

Owning a jet ski and a boat will guarantee a greater water fun, one is the complement of the other. For me those are delicate costly toys that drains a lot more money than an outbord, at least that's what I constantly see at my boating Club.

Happy Boating

 

[QBhoy]

It of course could be a blown hose, but on this particular ski, it’s almost certainly the well known and documented carbon seal failing. They aren’t called Sunkdoos for nothing.
On the idea of the operator being aware the craft was taking on water...although I’m a jet skier myself, unfortunately there are an alarming number of owners of such crafts, that just aren’t savvy at all. Not the way your average boat owner would be perhaps.

 

[racerone]

Saw a sign years ago at a Yacht Club-------" We do not have the facilities to refuel jetskis / personal watercraft "------We all said that it was a polite way of saying ----GO AWAY !!

 

[JimS123]

Saw a sign years ago at a Yacht Club-------" We do not have the facilities to refuel jetskis / personal watercraft "------We all said that it was a polite way of saying ----GO AWAY !!

My son and I stopped at a local marine gas station one time, each of us on a different 'ski. The owner reluctantly gave my son the hose, all the while looking at me bashing jet skis. PO'd my son, so he only put in a few gallons - just enough to get home. That angered the owner even more, saying he wasted his time coming out of the store for that. When my son gave him the credit card, he really lost it, saying he had a $100 CC minimum. We asked him to show us the sign, and he didn't have one. My son had no cash, and i left my wallet home.....LOL.

We have many friends at the local Yacht Club. As the story goes, two women on 'skis from the club got the same treatment, and told their husbands. The 2 families both owned 40 footers. Well, the word got around and everyone from the club stopped doing business there.

Anybody can conduct their business any way they like. You just have to put up with the consequences if you aren't polite to your existing or potential customers. What the idiot didn't know was that my son's other boat has an 80 gallon gas tank that he'll never have the opportunity to fill up.

 

[racerone]

Well I also know my local auto repair shop stopped selling gas about 10 years( or more ) ago.------Still says it is the best thing he ever did.

 

[Sea Rider]

Everyone owning a Seadoo jetski is complaining about the carbon ring wearing way fast and the jet ski going submerged. Don't know if the Service Manual specifies changing it at certain run hours. The spare part is $ 150 + $ 50.00 labor + $$$$ ??? recovering the engine after submersion...

Happy Boating

 

[JimS123]

Everyone owning a Seadoo jetski is complaining about the carbon ring wearing way fast and the jet ski going submerged. Don't know if the Service Manual specifies changing it at certain run hours. The spare part is $ 150 + $ 50.00 labor + $$$$ ??? recovering the engine after submersion...

Happy Boating

Gee I wish I knew that before?

We had a 2003 GTX 4-Tec for 13 years. Traded it in 2015 for a Yami, and we're Yami forever now, but that's another story.

Anyway, as I recall we had about 600 hours on her at the end. I did follow the Maintenance Schedule, and the carbon ring was the original when I sold the 'ski.

Just looked at the old manual, and it said to "inspect" the ring every 50 hours or 6 months, and replace as necessary.

 

[Sea Rider]

A yami is much better, uses a seal holder which lasts way longer.....

Happy Boating

 

[wahlejim]

As mentioned, the Sea Doo line up had carbon ring issues. It is easy to spot by taking the seat off. It looks like someone took a pencil and drew a circle around the engine compartment right in line with the seal. Racing machines make sense as they are usually flashing the computer to over ride the governed RPMs. Higher RPMs require more durable components. There are warning signs that are being ignored.

Yamahas are not without issues either. Most recently, the fiberglass around the area that the ride plate bolts to the hull had issues. The ride plate would gradually pull out of the hull, accompanied by cracking and water intrusion.

The main issue at play here is the USCG requirements of manufacturers shipping machines with the speed limited, I believe to about 68 mph. Of course, these 300hp+ machines are capable of higher speeds. Manufacturers, however, have been focusing that horsepower to acceleration over top end. In order to compete with each other, they have made hulls out of different composites that are lighter. Sacrifices have been made in overall strength all in the name of shaving a couple of tenths of a second off the 0-60 time.

Kawasaki seems to be the only player that has kept full fiberglass hulls and opted for strength and durability. They are not has fast as Sea Doo or Yami, but they are plenty fast for your every day rider and feel a lot better in the chop.

I should mention that most of the issues that have occurred in regards to a catastrophic breakdown are the higher end, go fast racing hulls. Your every day rider on a cruiser will not run into these issues. The inexperienced races that just want the fastest machine often cut corners, ie, do the basic/cheapest/most effective improvements without beefing up related components.