Aqua drive is it worth installing

I just replace my transmission with a new model but slightly different size and I'm not happy with the alignment. I'm try to decide if going with aqua drive is worth it. The boat is a 42ft steel hull with a single perkins 6.354. I suspect I will put it in but if anyone has any feed back that would be great.

Not worth having for that reason.

The AD is the ideal drive. You need to do a very fussy alignment during installation of the thrust bearing but alignments after that are not so fussy. You need to maintain about 2 degrees MISALIGNMENT while using the AD.

Knowing only your #1 post I'd say just buck up and do a good job of alignment.

Back in the mid 80s I retrofired an aqua drive to a trawler and it really helped with noise and vibration. Just 3 years ago I sold a different boat that came with Aqua drive so I have no way of knowing what the difference would be. My present boat does not have Aqua drive but the motors are very smooth running common rail. I think it comes down to the individual boat and motor combo and how rigged and mounted. If you are feeling a lot of vibration and its not from prop or bent shafts then I would say go for it.

funangler said:

I just replace my transmission with a new model but slightly different size and I'm not happy with the alignment. I'm try to decide if going with aqua drive is worth it. The boat is a 42ft steel hull with a single perkins 6.354. I suspect I will put it in but if anyone has any feed back that would be great.

Click to expand...

I think I heard that Fleming yachts have them.
I have no experience myself but I would also like to know about them.
Check in your area if you can talk to a fleming owner.

Aqua drive is great as it reduces one more required skill set.

Some folks can eventually line up an engine to the shaft, , but aging flex mounts eventually pull it out of line.

The hard part of the Aqua Drive is fixing REQUIRED the thrust bearing to the hull properly.

When that is done you are home free.

Yes it should be 2-5deg out of line to properly lube the drive joints.

If the boat was built with wide spaced engine mounts a future engine replacement would be much easier.

When out of service for a long time they can stick, and operate out of line , a blast of throttle is all it takes to un-stick them for another season.

The problem I find is my shaft is not supported for 6 ft from a pillow block bearing and it allows for a lot play in the shaft. The boat is steel adding a thrust plate is easy. Moving the engine 2-3 inches out of alignment is the challenge.

For those not familiar w the AD it isolates the engine's vibration from the propeller shaft and stops the propeller thrust from reaching the engine, it's mounts and the thrust bearing in the transmission. It does this w a CV joint like on FWD cars and the inclusion of a thrust bearing aft of the transmission. The CV joint is located between the Tx and the added thrust bearing. The CV joint responds to all the engine's movements. Heaving, thrusting, pitching, radial movement (torsional), sideways movement and yawing.

SO ...

The engine no longer shakes the propeller shaft.
The engine mounts no longer need to have a compromised design to accommodate the thrust from the propeller shaft.
Much softer engine mounts can be used for better vibration isolation.

Other products are on the market now as AD's patent ran out a number of years ago. Python Drive comes to mind. Then there's the Evolution Drive that is quite different from the AD types and I know little about it.


funangler,
There are standards for the length of unsupported shaft considering the diameter that is acceptable. Find out if your length/dia falls within the acceptable guidelines and if not add another shaft bearing preferable not in the middle of the run.

If there is runout on the unsupported section of the shaft, often that is caused by runout on the coupling flange relative to the shaft center. This "kicks" the shaft off center, and the runout gets worse the further from the coupling, until shaft is supported by a bearing which brings it back to center.

Often this probem shows up when the flanges are separated for some work and put back together in a different orientation. It can be as simple as a thin layer of rust on the flange faces!!! I have cured several of these by simply breaking the flanges and cleaning the mating faces. Clean clean clean!! Put back together and runout is gone.

If you are using a solid coupling, these can be difficult to get a smooth running shaft. They come either too tight or too loose. And flange faces can have just a few thou of runout and that is enough to kick shaft off center down the line.

For that reason I like using split couplings. Better grip on the shaft, too.

One trick (besides cleaning flanges) is to loosen bolts on coupling flange and then roll shaft- If runout is gone, there is a runout problem on the flanges.

If the only problem is shaft wobble, I would try to fix that first before going to AD. AD is a nice rig, but that is a lot of work and expense to fix a problem that may be easily done another way.

manyboats said:

There are standards for the length of unsupported shaft considering the diameter that is acceptable. Find out if your length/dia falls within the acceptable guidelines and if not add another shaft bearing preferable not in the middle of the run.

Click to expand...

Manyboats: could you explain why not to add a shaft bearing in the middle of the run please?

Moving the engine 2-3 inches out of alignment is the challenge.

Simply lower the front , or install different height engine mounts, or slip the rear of the engine sideways to have a bit of shaft misalignment.

One delight is far softer mounts that will pass less vibration to the ship can be installed.

The exhaust , fuel lines and the rest of the hookups may have to be modifies for the bigger engine dance.

Aquabelle said:

Manyboats: could you explain why not to add a shaft bearing in the middle of the run please?

Click to expand...

Yup! I would like to know what's behind that too.

Wish me luck I have ordered an Aqua Drive. I now have to suspend my motor and change my entire mounting system along with everything else that attaches to the motor. With luck I should report back in a few weeks if I'm happy with the drive system.

The PO put one in mine and I like it .I talked with him about 6 months ago and he was installing one on the tug that he has now.

Shoalwaters and Aquabelle,

Yes. The shaft has a resonant frequency due mostly to it's length. If there is something nearby that's connected in a way that vibration could be transferred to the shaft (like a buzzing engine) the shaft will respond by shaking or buzzing to the same frequency as the exciter (the engine). Not much vib will be transferred unless or until the engine gets to the shaft's resonant frequency. Then the shaft will get really excited and humm w significant noise and vibration. Like a tuning fork. Clamp a tuning fork at it's halfway point and it will vibrate at twice it's normal frequency. Make that tuning fork a rod or bar. Now both ends will vibrate most violently at it's resonant frequency as one end will excite the other and amplify the overall vibration. Now clamp the bar (or prop shaft at a 60/40 length ratio and then neither end can excite the other as they have different resonant frequencies because of their different lengths. I don't know any length ratio that is most beneficial to minimizing vibration but one should probably avoid thirds and quarters and perhaps resonate harmonics could be taken into consideration but just putting the mid supporting bearing a bit off from center may reduce boat vibration considerably. Like 60/40 or 55/45 or thereabouts.

Thanks Eric, that little piece of info may prevent me from doing the wrong thing one day.

I did put one of them!

Yeap...I did install one of them

BE CREFULL, IT WILL CONSIDERABLY PUSH YOUR MOTOR FORWARD.

Wow nice bilge!

Portuguese wrote;
"BE CREFULL, IT WILL CONSIDERABLY PUSH YOUR MOTOR FORWARD."

I don't understand. The AD thrust bearing should keep the shaft from pushing the engine fwd. It will push on the AD thrust bearing and then the thrust will be transferred to the hull by the thrust bearing mounts. Usually the thrust is applied to the transmission and transferred to the hull through the engine mounts and engine beds.

Unless you have an AD or equivalent your engine mounts need to be designed to handle the thrust of several hundred pounds. This design necessity makes most engine mounts less capable to isolate engine vibration. AD makes their own special mounts to be used w the AD only.

Oh Port ... it just dawned on me what you meant. You need to shorten your drive shaft to accommodate the AD. It's part of the installation drill.

Above Yacht pricing , the commercial folks have ball bearing intermediate bearings that are a snap to install or replace..

They are built so the top cap unbolts and 1/2 the bearing set can be lifted out.

A push with a screwdriver and the bottom half of the bearing and race will slide out.

The bearing and races are split , so its all new (except the housing) when reassembled.
Beautiful machining does the trick , not made in China.

If there is working room total time to replace the bearing 3-5 min.

Isn't that similar to what uncoupled suddenly and unexpectedly on Mark's Coot when the boat was fairly new, while he was docking...??

Aquadrive system installer in PNW

I've decided to install the Aquadrive system in my trawler to alleviate aliagnment problems that go back to an earlier repower. Has anyone installed one in their boat? Can you recommend a boatyard or mechanic in the PNW who has experience specing and installing these systems? (I asked the regional AD distributor for referrals but they were unable to provide any?)

I got my AD from Drivelines NW in Everett. Installed it myself.

They should know boatyards to recomend. Boatyard work seems always a mixed bag so I don't like to recommend. I've heard, however Boat Diesel in Anacortes is good.

Go to the people that sell engines like Gallery Marine in Seattle. An AD install should be a walk in the park for good engine installer.

Eric, Gallery Marine was responsible for the botched repower in '07.

nwboater,
Oh ... Already have them on my undesirable lets not go there list. Not from personal experience however. Almost bought my new engine from them. They had in their lineup at the time a 42hp Kabota/Universal engine. Very heavy, all cast iron and rated at 2500rpm. Before I choose an engine it was no longer available ... probably wouldn't meet "Tierll" EPA.

With my present Mitsubishi they are a backup parts source for the base engine.

Is Gallery Marine making any moves toward accepting responsibility for your bad installation? Sure hope so. Glad I didn't recommend Gallery specifically.

I had an aquadrive on a previous boat. It was standard equipment from the factory. It seemed to work well. One recommendation; coat the entire assembly with anticorrosion spray once or twice a year. I used Woody Wax and then switched to CorrosionX. If you don't do this, the aquadrive will rapidly build up a coating of rust.

nwboater said:

Eric, Gallery Marine was responsible for the botched repower in '07.

Click to expand...

My just finished experience with Townsend Bay Marine in Port Townsend was excellent. They are the first yard I have ever dealt with that was 1). reasonably priced ($60/hour), and 2). completely competent. They prepared an estimate of the likely cost of the work that needed doing (cutlass bearings, bottom paint, prop work, PYI shaft seal maintenance, thruster and fin servicing) and hit it pretty much on the nose even though I added some things and didn't do some things I thought needed doing based on their recommendations. They took pictures of everything they touched, and prepared a 1 1/2 page commentary on things to think about. They noticed and commented on a number of open issues. For example, bow thruster port and starboard props reversed (happens about 50% of the time, they say), engine out of alignment (unexpected, since I have paid two other yards twice to do precisely that but it clearly has never been done correctly), noted that one of the floor boards in the E/R was in contact with the shaft, etc.

In addition, when we found that the i.d. of the stern tube was some weird metric (built in Norway in 1965) while the cutlass bearings were 15 thousand bigger, the manager took them home to his shop and turned them to fit.

Another upside is that the lifts are owned and maintained by the Port of P.T., meaning they are in great shape with very professional operators. Great experience.

Downside - like all boat yards the amount of dust and crud you collect in 10 days on the hard is hard to believe. Took me 4 hours to clean it all off. But I am not complaining and this would be my first recommendation in the NW for a yard.

Were I installing an aqua drive, these would be the first guys I would talk to.

@ Delfin

4 hours to clean a vessel as lovely as your would be seen as a blessing to me. I can't get away with 6 hours. I find the parts I painted myself take 30 minutes compared to the decks that had a flatten agent and professionally applied takes way too much time. Add to the equation that the only thing in life I feel anal about is a boat deck.

Just to keep on topic: I love my aqua drive. It is original equipment, but I have replaced the CV joint once due to boot failure. Then I became enlightened to the fact that a racing style CV joint boot for a VW racing setup was the way to source my fix.

Pegasus Racing out of Wisconsin supplied the boot for K-mart pricing. Why the boot fails and needs replaced is still mystery to me. The actual CV joint was fine but the grease thrown from the failed boot causes quite a mess.

Choose the installer with great care .

It is far harder to engineer and mount the thrust bearing than simply R&R an engine.

Maybe I missed this in Posts... But... What is average cost for aqua drive unit and its professional installation per engine?

Art, two years ago I bought a new AD joint and it was around $475 not including the bearing support as the boat has one. I would guess adding one to a boat that was not set up origionaly would be $2k or $3k each depending on ease of shaft removal and adding a support for the bearings.

Not mine