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July 2011

The Problem:  Seawater intrusion through the Port Stabilizer assembly.

After departing from Ashiya, Japan on May 5, I noticed that there were a few drops of salty water dripping from the top of our port stabilizer.  I first …

July 2011

The Problem:  Seawater intrusion through the Port Stabilizer assembly.

After departing from Ashiya, Japan on May 5, I noticed that there were a few drops of salty water dripping from the top of our port stabilizer.  I first checked the torque of all of the bolts that were accessible, and then put a small bowl below the unit and monitored the flow hourly.  This was a slow leak, maybe a tablespoon a day. About 600 nm out of Ashiya we stopped at Chichijima and I dove under the boat and found some large mussels wedged between the top of the fin and around the shaft; I wondered if maybe a piece of mussel shell was wedged into the seal?  Naiad assured me that the fit is much too close than what would allow pieces of shell into the space occupied by the seals.  The dripping stopped after about a week of running.

The trip to Hawaii took 24 days. Upon our arrival in Honolulu I made arrangements to haul out. The bottom needed paint and after two years and 15,000nm of running, it was time to check the stabilizer seals. Starr was hauled out at Keehi Marine Center.

Starr Haul-out (click to enlarge any picture)

I pulled the fins with tools I carry on board: a 10 ton hydraulic power pack, a 600Ft Lb torque wrench, and all of the necessary tools to do our own work. 
Note: see the excellent article on seal replacement by Scott Flanders, Voyage of Egret 7-21-2011
http://www.nordhavn.com/egret/captains_log_july11.php

The last time I pulled the stabilizer system and replaced the bearings was in 2001 in New Zealand. At that time I was 58 yrs old and now I am 68.  THIS WAS NOT MY IDEA OF FUN!!  I have a great deal of respect for the Naiad factory people from Seattle, and I would have liked them to do the job; unfortunately, they were all committed elsewhere.  I decided that I would have to do the work myself. SOME PEOPLE NEVER LEARN.

Port stabilizer showing leak trail. (click to enlarge)

(click to enlarge)

After popping the fins off, I pulled the seals.  My first observation was that the seals were heavily coated with RTV, even into the expansion “V” grooves, and didn’t even come close to resembling the factory recommendations.

 I removed the seals using a power screwdriver and 3-inch screws. The seals were packed on all sides with RTV.

As you can see, the seals were improperly packed full of RTV when they were last replaced in Seattle two years ago. I don’t think it’s a poor guess to think that the expansion/flexing space in each of the seals was “locked up” with the RTV being jammed throughout the whole seal assembly.  Even though it was obvious that the seals were improperly installed, it was impossible to clearly determine the condition of the grease. The only way to be sure was to pull the bearing retainer plate to see if the grease was contaminated.

With the bearing retainer plate removed, it was clear to see that the previously white grease was now black with contamination.

 The bearing retainer is removed and the white grease has turned black with seawater contamination showing. (click to enlarge)

The next task was to drop the shaft in order to get to the bearings, and see if the seawater had damaged them.  To accomplish this I had to work my way down from the top, starting with the potentiometer, then the cover plate, (I was careful to lift the cover plate evenly so as to not break the hydraulic ram trunion roller bearings), then the torque arm, and finally the seal wiper and seal. When the shaft was loosened it didn’t want to drop out so I made a driver out of heavy-walled stainless pipe and drove it out with a 5# sledge hammer.  Once the shaft was out, the next job was to pull the sleeve and the bottom bearing. This was made easier by using a puller made from ¾-in all-thread, and a heavy bottom plate and a top plate of a slightly smaller diameter than the sleeve OD.  With the sleeve and bearings removed, I examined the bearings and determined that they had damage from the water intrusion.  New bearings and races were delivered the next day from Naiad’s factory.  Yay Naiad!

Shaft and bottom bearing with seawater contaminated grease. ( click to enlarge)

Top  Seal and wiper where seawater was exiting.  (click to enlarge)

Sleeve and bottom bearing.  (Note that the grease is clean on the sleeve exterior. The water went in between the shaft and the sleeve.)

 Port actuator

Port actuator with sleeve out, and bearing races still in place. I took them out using a 1½-inch x 18-inch bronze driver (cut from an old prop shaft).

Working on the starboard actuator. (If only the guys who design and build boats had to repair each piece of equipment, then access would be different!)

 New bearings and races: Due to the close tolerances between the bearing and sleeve one must either use a press or heat the bearings.

 Freezing the sleeves.

Heat the bearings to 200 degrees F for 2 hours (and then baste twice).

 Dinner is served: Hot and cold entrée!

Viola! The only other way to get the bearing on was to press them on. This is much more fun!

Time for reassembly:  Tap the top-bearing race into the housing, then grease the sleeve and pack the bearings.  (It was not possible to get the Lubriplate grease that Naiad specifies in Honolulu, so I had S3 ship it overnight from Seattle).

It was necessary to make up a puller using (5) 7/16” fine all-thread bolts to suck the sleeve and bottom bearing back into position.

At this point it was time to replace the seal and wiper, and then to preload the sleeve into its bearings.  Unlike with many shaft/bearing installations, no shims are needed in this assembly because Naiad is able to control the dimension of the sleeve so precisely during their manufacturing process.

After reinserting the shaft, I chose to raise it up another 3/8 of an inch so that the bottom seals would ride on new shaft surface material.

 It is important to keep in mind that the only thing holding the shaft and the stabilizer in the boat are the two torque arm side-bolts which are torqued to 95Ft Lbs. (see bolt #42 and 43 in the Naiad shop drawing above) that squeeze the torque arm around the spines milled into the top of the shaft .

 

While it may look like the large nut on the top of the stabilizer shaft is doing the job of keeping the shaft in the boat, IT IS NOT!!!  Its principal job is to act as the shaft height adjustment nut. The real shaft retaining work is done by the squeeze the torque arm is performing around the shaft splines.

The balance of the reassembly went quite fast, as did the final realignment of the potentiometer so the center lock pin drops in place as it should.

 The sleeve and bearing package is preloaded to 60 FT Lbs torque.

Buttoning up.

Almost done. What a beautiful bottom!!

 Dave Schmidt and I cleaning the fin shaft and pocket with brake cleaner.

 Up a smidge please.

Torque to 300 Ft-Lbs

Do we make the fin parallel with the keel?  Why not toe it out a bit?  What is the water flow like at the stabilizer?  Let’s toe it out about 3 inches!

Twenty gallons of bottom paint later: I decided to use International 640, but will it work?  After asking the local commercial fleet operators, it looks like a coin-toss on what bottom paint works best here in Hawaii.

Splash time.

You can be assured that the next time that the seals need to be replaced, the work will be done by someone else but I will be there watching!!

A BIG THANKS to my SENSEI:  Even though Dick McGrew, Naiad’s Pacific Ocean Tech was on vacation, he would respond to my many telephone calls with my questions; and Doug Janes ,who has been doing Naiads since Naiad started, was, and is, an invaluable source of knowledge, help, and support!!

Dick McGrew

Technical Services Manager for the Pacific

Naiad Dynamics

dmcgrew@naiad.com

206 359 0500

Doug Janes

J3 Systems

425 345 1470

jjj.sustems@frontier.com

Ryan Parker

S3Maritime

206 491 1595

ryan@s3maritime.com

MV STARR:  A Northern Marine 75’ LLC
Starr’s Voyage to Hawai’i – Impressions of a Nordhavn Owner
written by Viktor Grabner

Starr at Waikiki Yacht Club – Viktor is the big guy on far left

Nordhavn’s are built to cross oceans. My own No…

MV STARR:  A Northern Marine 75’ LLC
Starr’s Voyage to Hawai’i – Impressions of a Nordhavn Owner
written by Viktor Grabner

Starr at Waikiki Yacht Club – Viktor is the big guy on far left

Nordhavn’s are built to cross oceans. My own Nordhavn 50, Loreley has a range of almost 3000 nm that enables it to reach any place on earth. Its build withstands the weather and waves the oceans might throw at it, and the on-board systems are built to run continuously and trouble free. Yet, my boat could have never done the trip we just took aboard Starr – 24 days at sea, traveling over 4000 nm.

It is of course interesting to compare and think about how a Nordhavn would have fared on this trip relative to Starr.

To say it right off – it’s impossible to compare two different boats unless they’ve been in exactly the same seas and weather. I kept thinking how my own boat would do in similar conditions and kept mental notes on wind, swells and waves, but a true comparison requires being in the same water at the same time.

During our voyage, we had dramatic variation on speed and fuel consumption – our speed varied from under 6 to over 9 knots, and fuel burn from 0.7 to 1.2 + MPG. While we varied speed sometime, most of these variations were caused by wind, waves, and currents – and significantly the latter, which seemed to have a mind of their own, and caused our speed to go up or down but as much as 2 knots in a few hours!

If you look at our fuel burn chart, you get an idea how much variation we had, and how we adjusted our speed to reduce fuel burn. This got better as our journey went on (and we suspect that lighter weight also helped,) and we arrived with nearly 1350 gallons in reserve.

Beyond fuel consumptions, there is plenty of discussion and debate on design of the “perfect” boat.

Starr is a proven cruiser – with more than 75k miles on her bottom, and nearly 10,000 hours on her engine, she has proven herself as a capable cruise boat. Interestingly she has some design features that are hot debate topics – notably her pronounced pilothouse forward design and a bulbous bow hull. Let me start though with the one vs two engine debate, and what constitutes a good back up in case of engine failure. 

Starr has a single Cummins NTA855M engine mated to a Deep Case ZF gear with 4.5:1 reduction swinging a 5 bladed 50” prop. There is no second engine, and no second shaft or prop. 

The shaft is fitted with a large gear sprocket that can be connected by a chain to a hydraulic motor that is driven by a hydraulic pump connected to either of the 20kw generators, giving emergency propulsion in case of engine or marine gear failure. This scheme obviously uses the same shaft and prop, so the backup would not be effective in case of fouled running gear or damaged or lost prop. 

This approach contrasts with the one used on many Nordhavn that use small engines, (such as a Yanmar 40hp sailboat engine on my Loreley or Luggers on the larger boats), using a separate gear, shaft and prop. The advantages of this approach are immediate readiness (don’t need to put on the chain,) and independent running gear. 

On our trip, the cummins didn’t miss a beat during its 530 running hours, and we never needed to think about backup power. In fact, in all the years of cruising, Don only used this backup power once, when a faulty solenoid shut down the fuel supply to the cummins – a problem he debugged and fixed in a few hours. 

I prefer Starr’s get home arrangement over the separate get home engine on Loreley, for simplicity and appropriateness of use – that is, its complexity, cost and time to engage relative to likelihood of needing to engage it. I believe the separate get home engine, while easy and fast to engage and redundant, adds a disproportionate amount of complexity, cost and maintenance to the boat, as would a completely redundant main engine. Starr’s get home arrangement, by contrast, is simple. And of course, we had plenty of bed sheets in case we needed to rig an emergency sail.

The pilothouse on Starr has a pronounced forward location. The forward windows are located barely 15 feet back from the bow. This gives the boat huge space aft, both in the salon as well as boat deck. Critics of this design argue that an aft placed pilothouse provides a far more comfortable ride with less pounding and pitching experienced by the watch crew. 

I have no experience with pilothouse aft designs (Loreley also has her PH forward,) so I cannot offer a comparison between the ride quality of the two different designs.

I can, however, say that during our entire trip, the ride in the PH was comfortable and watchstanding was easy.  Pitch was soft with little pounding. There were only a few hours when things had to be secured from falling or tipping over (like our water drinking bottles.) As I write these lines, we’re headed into 5′ swells with 4-5 ft waves and 14 kts of wind, all about 20 degrees to the port of the bow. We keep the port PH door closed to avoid spray, but have the starboard door wide open for air and sunshine. Were pitching, but not in a jarring way, and my water bottle stays put on the dashboard. 

The bulbous bow is also an area of extensive debate. Critics cite poor sea kindliness against weather, and argue that the efficiency benefits don’t exist or are even less efficient than a fine bow design. My opinion is biased, as my boat Loreley is also equipped with a bulbous bow and has offered a ride similar to our experience on Starr. In short, we’ve not experienced poor ride, spray or rough pitching or noise caused by the bulb. Not having a way to compare it to a boat without a bulb in this water makes it impossible to compare, but the subjectively experienced ride is comfortable, and no crew member, even when asked, felt that the boat rode poorly or uncomfortably.

As to the efficiency – again, comparisons evade us – over the 4000 miles of our trip, we managed a 1 MPG at an average speed of 7-8 kts, with currents, wind and waves against us 100% of the time. 

These impressions are subjective and I doubt they will settle any debates. Ultimately the test of a good cruising boat is the question of whether the crew would be willing to do the same trip again? My answer is yes – our three weeks aboard have been comfortable and safe and I would not change a thing.

One last thought – in all the discussion over what makes the perfect cruising boat, among the most important elements is the crew itself – a good crew can overcome mechanical problems (to a degree of course..) while a poor crew can make the best boat a miserable experience. We had a great boat and an excellent crew – a perfect combination. I’m convinced that any Nordhavn, well maintained, with a carefully matched crew, can offer the same quality passage as we had on Starr.

Viktor was also Starr’s “official” photographer

MV STARR:  A Northern Marine 75’ LLC
Starr’s Voyage to Hawai’i – Impressions of a Nordhavn Owner
written by Viktor Grabner

Starr at Waikiki Yacht Club – Viktor is the big guy on far left

Nordhavn’s are built to cross oceans. My own No…

MV STARR:  A Northern Marine 75’ LLC
Starr’s Voyage to Hawai’i – Impressions of a Nordhavn Owner
written by Viktor Grabner

Starr at Waikiki Yacht Club – Viktor is the big guy on far left

Nordhavn’s are built to cross oceans. My own Nordhavn 50, Loreley has a range of almost 3000 nm that enables it to reach any place on earth. Its build withstands the weather and waves the oceans might throw at it, and the on-board systems are built to run continuously and trouble free. Yet, my boat could have never done the trip we just took aboard Starr – 24 days at sea, traveling over 4000 nm.

It is of course interesting to compare and think about how a Nordhavn would have fared on this trip relative to Starr.

To say it right off – it’s impossible to compare two different boats unless they’ve been in exactly the same seas and weather. I kept thinking how my own boat would do in similar conditions and kept mental notes on wind, swells and waves, but a true comparison requires being in the same water at the same time.

During our voyage, we had dramatic variation on speed and fuel consumption – our speed varied from under 6 to over 9 knots, and fuel burn from 0.7 to 1.2 + MPG. While we varied speed sometime, most of these variations were caused by wind, waves, and currents – and significantly the latter, which seemed to have a mind of their own, and caused our speed to go up or down but as much as 2 knots in a few hours!

If you look at our fuel burn chart, you get an idea how much variation we had, and how we adjusted our speed to reduce fuel burn. This got better as our journey went on (and we suspect that lighter weight also helped,) and we arrived with nearly 1350 gallons in reserve.

Beyond fuel consumptions, there is plenty of discussion and debate on design of the “perfect” boat.

Starr is a proven cruiser – with more than 75k miles on her bottom, and nearly 10,000 hours on her engine, she has proven herself as a capable cruise boat. Interestingly she has some design features that are hot debate topics – notably her pronounced pilothouse forward design and a bulbous bow hull. Let me start though with the one vs two engine debate, and what constitutes a good back up in case of engine failure. 

Starr has a single Cummins NTA855M engine mated to a Deep Case ZF gear with 4.5:1 reduction swinging a 5 bladed 50” prop. There is no second engine, and no second shaft or prop. 

The shaft is fitted with a large gear sprocket that can be connected by a chain to a hydraulic motor that is driven by a hydraulic pump connected to either of the 20kw generators, giving emergency propulsion in case of engine or marine gear failure. This scheme obviously uses the same shaft and prop, so the backup would not be effective in case of fouled running gear or damaged or lost prop. 

This approach contrasts with the one used on many Nordhavn that use small engines, (such as a Yanmar 40hp sailboat engine on my Loreley or Luggers on the larger boats), using a separate gear, shaft and prop. The advantages of this approach are immediate readiness (don’t need to put on the chain,) and independent running gear. 

On our trip, the cummins didn’t miss a beat during its 530 running hours, and we never needed to think about backup power. In fact, in all the years of cruising, Don only used this backup power once, when a faulty solenoid shut down the fuel supply to the cummins – a problem he debugged and fixed in a few hours. 

I prefer Starr’s get home arrangement over the separate get home engine on Loreley, for simplicity and appropriateness of use – that is, its complexity, cost and time to engage relative to likelihood of needing to engage it. I believe the separate get home engine, while easy and fast to engage and redundant, adds a disproportionate amount of complexity, cost and maintenance to the boat, as would a completely redundant main engine. Starr’s get home arrangement, by contrast, is simple. And of course, we had plenty of bed sheets in case we needed to rig an emergency sail.

The pilothouse on Starr has a pronounced forward location. The forward windows are located barely 15 feet back from the bow. This gives the boat huge space aft, both in the salon as well as boat deck. Critics of this design argue that an aft placed pilothouse provides a far more comfortable ride with less pounding and pitching experienced by the watch crew. 

I have no experience with pilothouse aft designs (Loreley also has her PH forward,) so I cannot offer a comparison between the ride quality of the two different designs.

I can, however, say that during our entire trip, the ride in the PH was comfortable and watchstanding was easy.  Pitch was soft with little pounding. There were only a few hours when things had to be secured from falling or tipping over (like our water drinking bottles.) As I write these lines, we’re headed into 5′ swells with 4-5 ft waves and 14 kts of wind, all about 20 degrees to the port of the bow. We keep the port PH door closed to avoid spray, but have the starboard door wide open for air and sunshine. Were pitching, but not in a jarring way, and my water bottle stays put on the dashboard. 

The bulbous bow is also an area of extensive debate. Critics cite poor sea kindliness against weather, and argue that the efficiency benefits don’t exist or are even less efficient than a fine bow design. My opinion is biased, as my boat Loreley is also equipped with a bulbous bow and has offered a ride similar to our experience on Starr. In short, we’ve not experienced poor ride, spray or rough pitching or noise caused by the bulb. Not having a way to compare it to a boat without a bulb in this water makes it impossible to compare, but the subjectively experienced ride is comfortable, and no crew member, even when asked, felt that the boat rode poorly or uncomfortably.

As to the efficiency – again, comparisons evade us – over the 4000 miles of our trip, we managed a 1 MPG at an average speed of 7-8 kts, with currents, wind and waves against us 100% of the time. 

These impressions are subjective and I doubt they will settle any debates. Ultimately the test of a good cruising boat is the question of whether the crew would be willing to do the same trip again? My answer is yes – our three weeks aboard have been comfortable and safe and I would not change a thing.

One last thought – in all the discussion over what makes the perfect cruising boat, among the most important elements is the crew itself – a good crew can overcome mechanical problems (to a degree of course..) while a poor crew can make the best boat a miserable experience. We had a great boat and an excellent crew – a perfect combination. I’m convinced that any Nordhavn, well maintained, with a carefully matched crew, can offer the same quality passage as we had on Starr.

Viktor was also Starr’s “official” photographer

***** A FIVE-STARR PASSAGE

April 30, 2011
Waikiki Yacht Club, Honolulu, HI
21degrees 17-12N/157degrees 50-35W

Gary & Jean and Don & Sharry
The CCA was well represented at the International Date Line

On February 19, 2011 Jean and I received…