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Old 02-06-2018, 23:51   #1
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Seahorse Marine Diesel Duck Vibration - Advice needed

I own a 55’ steel Diesel Duck (DD542) trawler yacht, which is a lengthened version of the very successful 48’ Diesel Duck (DD462) built by Seahorse Marine in Zhuhai, China (Zhuhai is few hours from Hong Kong). The boat is now registered in Hong Kong since 2014.

DD542 is beautifully built like its DD462 cousin, except it vibrates. Seahorse knew about the vibration then (unfortunately I did not), but chose to deliver the boat. Seahorse probably felt the problem was simple to fix (relocating the whip bearing), and could be handled without returning to the yard after delivery.

Seahorse has by now tried all simple fixes in sub-contractor yards without success. The boat needs some serious trial and error troubleshooting while sitting in a yard for an extended period. Hong Kong yards are extremely expensive for this potentially very prolonged work, so Seahorse refuses to involve another sub-contractor yard.

The obvious action now is for the boat to go back to Seahorse yard in Zhuhai. But Seahorse will not bring the boat back to its Zhuhai yard, citing an unreasonable China government policy, that the boat must be towed ($$), and they must pay a hefty but refundable bond at 43% boat value ($$$$).

Unreasonable the policy maybe, the policy was known to Seahorse at the time of delivery, and it boggles the mind why Seahorse still chose to deliver a defective boat, and end up hurting everyone including itself.

Anyway I am now stuck with fixing the boat myself, if I do not want to wait for the government policy to change (I have been waiting for three and half years). I have very limited financial means, so I cannot afford any unnecessary trial and error. I hope this post brings me some advices from the community, how to be smart in going about this. Here are some facts, questions, and plans:

1. Vibration increases with load (none in idle) regardless of forward or reverse. Vibration becomes unmistakably noticeable at 1200rpm and increases with rpm. However at about 1900rpm vibration dampens down RELATIVELY; at very high rpm around 2200rpm (engine max out at 2500rpm), vibration not only is pronounced, it goes through cycles of peak and trough every few seconds, as if something is flexing then bouncing back.

2. Compared with the very successful DD462, DD542 has a longer shaft at 4 meters (about 31cm longer than DD462), at the same diameter of 2”. Seahorse (Bill Kimley) is adamant the shaft is not too thin (engine power is 178hp), and this claim seems to agree with calculations by reputable shaft suppliers.

3. However there is a concern where to place the whip bearing for such a long shaft, between the shaft exit Cutlass bearing, and the (forward) thrust bearing. Seahorse experimented with the location and has relocated to the presently just about at the middle of the shaft, about 1.8 meter from either the Cutlass bearing or the (forward) thrust bearing. So the shaft is on one end supported by Thrust Bearing, the other end by the shaft exit Cutlass Bearing, and in the middle by a whip bearing. This should conform the guide line of 40xdiameter (of shaft) which is 2 meters. But there is no improvement on vibration.

4. At this point engine, engine mount, engine alignment, propeller type, propeller size, shaft straightness (checked when pulled out), whip bearing location have all been checked and tried. The latest attempt was to check if the 3 blade Max prop (feathering), new to Seahorse Diesel Ducks, was the cause. A smaller fixed 4 blade prop which generated maximum 50+% power was installed. If there is no vibration the plan was to then go for a 100% sized fixed 4 blade prop. The vibration was less, BUT STILL VERY evident despite the reduced loading. Incidentally Seahorse (Bill’s wife Stella) actually took this as an improvement. It boggles the mind again …

5. I contacted the late George Buehler who is the father of the wonderful Diesel Duck design. George told me about earlier Seahorse Diesel Ducks, and suggested me to buy a new name brand shaft. Based on what he saw with an earlier 55’ Diesel Duck built by Seahorse, the Chinese made shaft “could not hold shape”. The earlier 55’ had such a bad vibration that the coupling came off. The problem was completely fixed by the owner after delivery, by changing out the shaft and re-aligning the drive train.

6. Seahorse (Bill Kimley) is adamant shaft material is not an issue, despite known shaft quality problems with the earlier DD55 (and a couple of DD462s according to George). But I am willing to give it a try. The "cycling of vibration with peak and trough" mentioned in Point 1 suggests the shaft is flexing under load. Such a job in Hong Kong would take a day in a Hong Kong yard, which I can pay IF IT FIXES THE PROBLEM, and demand repayment from Seahorse.

7. I plan to install a proper name brand shaft and re-install the original 100% Max Prop. I ask for advices from the community, if anything else obvious I should account for with my limited financial means.


Thank you all in advance.


The owner of Seahorse Marine Diesel Duck DD542
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Old 03-06-2018, 05:19   #2
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

Here at SBYC Subic, have got to know a lot of the Duck Owners who were going thru their teething issues after delivery.

Do you know Ray Wolfe?
He worked as commissioning surveyor and Yard QC for the Seahorse owner, until he fel out of favor with Bill's wife!

If not, I can give you his contact as he is very knowledgeable about Seahorse.

It does sound like a torsional vibration issue and while you can expect the worst vibration at standard engine critical (around 1200rpm), the fluctuations at different speeds, indicate a poor quality shaft that is unbalanced and flexing under load.

I think your suspicions are correct, but unfortunately you will have to buy a quality one and replace, to prove it to the yard.

Good luck at solving the problem.
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Old 03-06-2018, 15:38   #3
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

Hello Pelagic:

I am so glad someone connected to the Seahorse DD crowd responded.

Ray Wolfe was initially hired by me over the web as the surveyor. At the time I was somewhat upset that he simply stopped showing up at the yard after a couple of initial visits. I was later to be told by another Seahorse DD Owner that Stella gave Ray a hard time, for Ray surveyed quite a few Seahorse boats and knew all the yard's dirty tricks. Too late for me then for the boat was delivered.

I was Subic much later and Ray walked by. Without stopping him I asked why he simply dropped my job. He said "Between Stella and Fido" then he gave a gesture of powerlessness and walked away. Fido is Stella's son from an earlier marriage.

Part of the problem in finding the solution to the problem, is Seahorse keeps you in the dark. A while ago Ray's response to me came up in a frustrating conversation with Stella. She would not admit to it and said Ray was still coming into the yard for surveying work.

Bill Kimley told me mine was the only Diesel Duck built by Seahorse that had vibration. Then I found out the very contrary from George Buehler. Bill and Stella will not face the mess they created from their conscious decision, yet they would not let the owner know enough to do something right ... That boggles the mind.

Going to Ray for help to clean up Bill Kimley's mess was actually on my mind. But even Bill Kimley said with the vibration I got, better not to risk taking the boat to Subic. But in view of the circumstances, I might re-consider.

I lost Ray's email address, and would very much appreciate you re-connect us. I might go meet Ray first in person, and hope to meet you as well over a beer or two.


Thanks again !


SeahorseDD54201
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Old 04-06-2018, 03:56   #4
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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Originally Posted by SeahorseDD54201 View Post

4. At this point engine, engine mount, engine alignment, propeller type, propeller size, shaft straightness (checked when pulled out), whip bearing location have all been checked and tried. The latest attempt was to check if the 3 blade Max prop (feathering), new to Seahorse Diesel Ducks, was the cause. A smaller fixed 4 blade prop which generated maximum 50+% power was installed. If there is no vibration the plan was to then go for a 100% sized fixed 4 blade prop. The vibration was less, BUT STILL VERY evident despite the reduced loading. Incidentally Seahorse (Bill’s wife Stella) actually took this as an improvement. It boggles the mind again …

7. I plan to install a proper name brand shaft and re-install the original 100% Max Prop. I ask for advices from the community, if anything else obvious I should account for with my limited financial means.
Coincidently, I just replaced my own 55mm x 3.5m shaft in 2016, with Australian Made via local company Translift, who did the final machining inhouse in Subic and supervised the installation (cost about USD5k). Drydocked at Watercraft.

I will send you Ray's email by PM and my WhatsApp # in case you wish to talk about Subic options.

Re your points #4 and #7
#4 If you put a 50% undersized fixed prop on a poor shaft, the increased cavitation will not help the harmonic vibration issue to go away completely

Also, Seahorse, seems to go thru a prolonged learning curve with new instalations so the original Max.Prop configuration may be a contributing factor

#7
If you choose to come to Subic, I would negotiate with Seahorse that you
are "Loaned" a full size Fixed Prop that you install and use at reduced power for the delivery to Subic. You bring along the MaxProp also.

This offers you more Data on original to discuss with TransLift plus the option to Sea Trial both the proper sized fixed and feathering Props after a new shaft is installed.
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Old 04-06-2018, 09:52   #5
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

I would change to a larger diameter, quality shaft.
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Old 04-06-2018, 09:54   #6
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

This may sound dumb? Have the motor mounts been thoroughly checked. I am assuming a whip bearing is a pillow block bearing. It wound seem you would notice a marked difference if the shaft is oscillating on both sides of it as opposed to what you previously had.
I guess if you have been told Chinese shafts have had problems, it may be better to get rid of it now.

Best of luck.
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Old 04-06-2018, 14:22   #7
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

Thx for the suggestion and the experience about Translift. I may very well end up getting their help
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Old 04-06-2018, 14:29   #8
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

Engine mount may need to be revisited, but it was checked, and Seahorse is experienced with it on all other boats. The whip bearing is a water lubricated Duramax which is physically identical to the prop end cutlass bearing. It is inacessible in the middle of the stern tube, which in turn sit inside and inaccessible in the long keel
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Old 04-06-2018, 14:43   #9
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

It may not be shaft whip, rather it may be a shaft torsional problem. If the shaft material isn’t up to the task it can load and unload rotationally.
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Old 04-06-2018, 14:51   #10
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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Originally Posted by SeahorseDD54201 View Post
Engine mount may need to be revisited, but it was checked, and Seahorse is experienced with it on all other boats. The whip bearing is a water lubricated Duramax which is physically identical to the prop end cutlass bearing. It is inacessible in the middle of the stern tube, which in turn sit inside and inaccessible in the long keel
I can't help but wonder it the cutlass at the prop end is not misaligned? It wouldn't take much.
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Old 04-06-2018, 15:48   #11
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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It may not be shaft whip, rather it may be a shaft torsional problem. If the shaft material isn’t up to the task it can load and unload rotationally.
It is the plan to replace the shaft with a quality brand. However for information, I don't think torsion is a problem. DD462 do not vibrate and have the same shaft and similar power characteristics. The only difference is DD542 has a longer shaft. A longer shaft with same power characteristics in my layman's mind would likely to deflect more than to twist more.
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Old 04-06-2018, 15:50   #12
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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I can't help but wonder it the cutlass at the prop end is not misaligned? It wouldn't take much.
The prop end cutlass bearing was checked and replaced. More importantly the boat was taken out of water, engine on and engaged. water injected to lubricate the bearing, and the prop turned smoothly (but no load as it is out of water).
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Old 04-06-2018, 15:52   #13
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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I can't help but wonder it the cutlass at the prop end is not misaligned? It wouldn't take much.
Prop end cutlass bearing was checked and replaced. More importantly the boat was out of water, engine on and engaged, water injected to lubricate the bearings, and the prop spinned smoothly (but no load, as it is out of water).
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Old 04-06-2018, 15:53   #14
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

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Originally Posted by SeahorseDD54201 View Post
It is the plan to replace the shaft with a quality brand. However for information, I don't think torsion is a problem. DD462 do not vibrate and have the same shaft and similar power characteristics. The only difference is DD542 has a longer shaft. A longer shaft with same power characteristics in my layman's mind would likely to deflect more than to twist more.


A longer shaft will also need to be more resistant to torsional loading. It’s longer, so is able to twist more than a shorter shaft while maintaining the same angular deflection per length.
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Old 04-06-2018, 16:01   #15
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Re: Seahorse Marine Diesel Duck Vibration - Advice needed

Hello Pelagic:

Thanks for sharing the experience at Translift, and I may well drive the boat over for their help. My boat is about 45 tons, and I hope it can be accommodated.

Also thanks for the suggestion on loaning a full size prop. Seahorse (Bill Kimley) is very generous with such parts. I wish he would be just as forthcoming in cleaning up his mess, instead of blaming the government.
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