Monday, February 6, 2017

The Case of the Cracked Flywheel Housing

Damaged Engine Mount (Rubber bushing)
In late 2015, we were on LUX, heading down the ICW to south Georgia where we were leaving LUX for a few months. We had just made it into South Carolina and Gee reported a new grinding type sound from the port engine (behind her bunk) when under way. Sure enough, it was distinctly different than the sound from the port engine. We had made it to Georgetown, SC by this time. We lucked out - a diver was working on zincs on another boat on the dock, so we were able to get him to check out the saildrives. He reported that the port drive was loose. A little investigation in the engine compartment with a light showed the engine mount on the saildrive seemed to be heavily worn and should be replaced. (See Damaged Engine Mount)

We called around and found one that could be shipped to Charleston, SC, where we planned to replace it. We motored the rest of the way to Charleston using the starboard engine except for docking. Of course, shipping parts to any port is fraught with risk and this was no different. It took all of the first day in Charleston to get the part and make it back to LUX.
Next, we started looking at removing the existing engine mount. Imagine our surprise upon looking closer and finding a crack in the flywheel housing. A closer examination showed that the crack was all the way around the perimeter of the saidrive’s connection to the flywheel housing.

Cracked Housing - Outboard
Our reaction was a bit stronger than “Oh No!” Our immediate thought was that it was going to require professional help and cost several thousand dollars to fix. Time to break out the phone and start making calls. The soonest we could be helped was the following week. Not only would it cost a bunch to make the repair, we’d be stuck in Charleston at an expensive marina. It was time to go to dinner and think about the situation. 

Think, think, think

How did it happen? The last charter in the BVIs was a disaster. LUX drug anchor and ran aground. Damage was fairly minimal, but the port prop took a few hits and had to be straightened. We think that a crack started then and four years of working back and forth extended it around the saildrive.

Cracked Housing - Inboard
It's Cracked All the Way Around!
Our port engine wasn’t totally out of commission. It could be used for docking as long as we didn’t need much power. We had made it from Georgetown to Charleston on one engine. Waiting in Charleston for repairs didn’t seem useful. There were other service companies in Georgia. So we decided to continue south, primarily on one engine.

As we made our way south, we thought about the problem, looked the engine over, and studied the parts diagrams. We could just slide the engine back about four inches and replace the cracked housing. Hmmm. Really? We had many hours to think on it. Checking eBay, we found a used flywheel housing that was much less than a new housing. We ordered it with shipment to our destination marina in Georgia. 

We thought about how to support the engine so we could decouple it from the saildrive and replace the flywheel housing.  We started collecting parts we thought would be of use. The end result was that we decided that we could to the job.

Doing the Job

Supporting the Engine
Mike orchestrated the repair, using an oak board, lines, and turning blocks to support the engine. It took most of the day to replace the housing. The old housing was indeed cracked all the way around the saildrive mount.

The new housing arrived in great shape and was soon installed and the engine coupled back to the saildrive.
Broken Flywheel Housing

New Flywheel Housing

The saildrive engine mount still had to be replaced. Just getting the old engine mount bushing out was a problem. It wouldn’t move. We had rented a car so we headed off to Tractor Supply, the source for all sorts of big parts. We returned with a 2-1/8 inch socket, a big wheel puller, all-thread rod, big washers, and a few other parts.
These parts did the job, allowing us to pull the old bushing and install the new bushing. We had to use heat on the saildrive mount to get the old bushing out and the new busing in (note the heatgun in the photo of installing the new bushing).

We were back to two fully functioning engines without having to spend too much time or money.
Removing the Engine Mount Bushing
Installing the New Engine Mount Bushing

Sunday, February 5, 2017

FlexoFold Props

Original Fixed Blade Props
LUX has had the stock two-blade fixed props that are outfitted on the charter fleet.
We had spent some time buddy boating with Dave on 5thQuarter and he was able to make better speeds at lower RPM, even though he had the 30HP Volvo MD2030 engines (LUX has the 40HP MD2040 engines). We recorded measurements of the performance at different points in time, shown in the table below, including 5Q’s performance, just for reference.
It was clear that Flexofold props were better. But they make a two blade prop and a three blade prop. Which one should we get?

Description (both engines running) RPM Speed (kn)
Before 2014 Haulout 2500 6.5
2800 7.1
After 2014 Haulout 2500 6.9

2800 7.3
Three months after 2015 Haulout 2500 7.1

2800 7.4
After 2016 Haulout (Flexofold props) 2500 7.4

2800 7.7

3000 7.9

3400 8.3
5th Quarter 2500 7.3

2800 7.6

Flexofold with PropSpeed
We asked Flexofold what they recommended for the MD2040 engines with the 130SR saildrdives (gear ratio 1:2.47). They responded that the three-blade 16x13 props would perform best. We agonized over the decision for a while and queried them about three-blade vs two-blade props, which 5Q and other Leopards we knew had. They told us that the extra blade helps with powering into seas and headwinds. The additional blade also provides better reverse performance. The pair of three blade props was $1000 USD more than the two blade props. We finally decided that the additional power was worth the money and ordered the three blade 16x13 props. They arrived within two weeks, nicely packaged. There was a small nominal charge from the shipper for entry into the US.

We have never had good luck with prop anti-fouling. It always seems to only last half the year. So we decided to try PropSpeed this year. It is an expensive anti-fouling for running gear. It has a tight timeline for application of multiple coats, so we had to be prepared and work quickly. We noted a number of boats being hauled had PropSpeed applied to the running gear and it seemed to be working for them. We’ll see…

We are happy with the performance of the Flexofolds. We can now motor on one engine at the same speed (in flat water) that we previously attained when motoring with two engines (6.6kn @ 2500rpm, 7.3kn @ 2700rpm). The motoring speed with two engines is improved (shown in the table above). Reverse performance seems about as good as with the fixed blade props. We did an informal quick stop test, similar to the one in the Yachting Monthly Folding and feathering propeller test magazine article of March 2015. The Yachting Monthly article reported stopping in 9.5 seconds, or 48 ft. In our test, we were able to go from 6kn to stopped in approximately one boat length (about 40ft). This is quite acceptable to us. Sailing performance also seems better, which we attribute to the folding props. The better motoring performance on one engine is also due to elimination of drag from the idle engine/prop. In summary, we’re quite happy with the Flexofold props.

Compression Ding Repair

Ground Out Ding with First Layer of Fiberglass
Every summer we tackle a list of projects that bring LUX closer to where we want her to be. The good news is that we seem to be getting close to the end of seemingly endless projects. This summer, we tackled a big compression ding on the port side, replaced the saildrive bellows, replaced the vibration dampener in the engines, and installed Flexofold props.

LUX had had a 6 inch diameter compression ding amidships, port. We ignored it last year (2015) as we were upgrading the standing rigging. This year's project started with the big grinder - grinding out the gelcoat and upper layers of fiberglass and feathering it out to a 12 inch diameter area.
Epoxy Workstation on a Walk Board
The fiberglass had delaminated from the underlying end-grain balsa. We drilled a few small holes in the fiberglass that remained. There are many opinions on whether to use epoxy or polyester resin on repairs. Our understanding is that polyester to polyester is only a mechanical bond, so we prefer epoxy, which also has adhesion. The Gougeon Brothers West Epoxy system has a lot of documentation and we’re experienced in using it, so that’s our go-to system for fiberglass repairs. We mixed some epoxy, adding cabosil (silica) to slightly thicken it, and injected it between the fiberglass and the balsa with a small plastic syringe.

Apply Pressure While the Epoxy Cures
The remaining epoxy was thickened and used to apply concentric circle layers of chopped mat and cloth to the surface of the depression. A piece of plastic sheet covered the still wet fiberglass and a squeegee was used to squeeze out the excess epoxy and bubbles. We then pressed a piece of flat foam on top of the plastic sheeting, backed by a piece of plywood. The whole thing was held in place by a set of walk boards.

12 inch Drywall Knife

24 inch Paint Shield

The area around the ding was masked off and the surface scrubbed and sanded to remove the amine blush that the West Epoxy system creates on the surface. The plastic sheet should prevent the formation, but we needed to sand it to create a “tooth” to help bond successive layers of repair. Low density fairing compound (#407) was mixed with epoxy and applied to the sanded surface. We used a 12 inch drywall taping knife to feather out the surface. 
As the surface came up to the same level as the gelcoat, we switched to a 24 inch painting shield to apply epoxy mixed with Microlight sanding filler (#410).

It took several coats of the Microlight epoxy mix to feather the repair to the same level as the gelcoat. We then used a sanding block and a 4-inch pad sander to sand it down slightly below the level of the surrounding gelcoat. The metal kedge of the 24 inch painting shield, bowed so that it followed the curvature of the hull, worked well for showing that the repair surface was slightly below the gelcoat. It helps to use some white tint in the epoxy in the final stages so that the underlying color isn't as dark.

Preval Sprayer Kit
Time for something new: spraying gelcoat. We had heard about using the Preval disposable sprayers for small gelcoat repairs. It is definitely at the low end of the quality scale for spraying gelcoat. The gelcoat was thick, even after thinning as much as we dared. The resulting surface has an orange peel dimple to it, clearly visible in the below picture. We knew that we’d have to sand down the orange peel dimples, so we applied several coats over the course of the afternoon, making a quick trip to the local marine supply store for more Preval sprayers. Only the refill compressed tank and sprayer valve was needed. We mixed the gelcoat in a small cup and sprayed directly from the cup.

Orange Peel Stipple Pattern
We used the finish version of gelcoat, so we didn’t have to spray an air barrier (PVA mold release) on the surface. Color matching was the difficult step. We’ve been slowly gaining experience with gelcoat color matching. The Leopards seem to use a brown tint, which we were not able to replicate using red, yellow, and black. The amount of each of these colors is simply too small to accurately get the right color. We finally found a small tube of brown color in a kit from Jamestown Distributors. A very small dimple of color paste on the end of a bamboo skewer is just about right for mixing with an ounce of white gelcoat. The Leopard interiors require a little additional color paste since they are more of an eggshell color than the topsides.

Ready for Sanding
Careful sanding of the gelcoat was required to remove the orange peel surface effect without getting too thin. We started with 220 grit on a pad sander to take off the high spots. Then it was time to remove the blue tape and plastic sheet and start wet sanding with paper around a wood block. We started at 320 and progressed to 600, then 1200. Patience is required. If you go too fast or too hard, the gelcoat gets thin and you can see the darker filler compound below. Feather it out to the surrounding gelcoat. Then we finished with a compounding wax and a buffer.

The entire process took us about a week, mostly due to waiting for the epoxy to cure. We also had to be careful of warm sun causing the epoxy and gelcoat to cure too quickly.

I didn’t have a final picture. But when I went to get one, I couldn’t find the exact spot. It must be a good repair if I can’t easily find it while looking from the deck.

Saildrive Bellows Replacement

Removing the Engines
LUX has Volvo MD2040 diesel engines with SR130 saildrives. To our knowledge, the bellows that seal out the sea water around the saildrives have never been replaced. The recommended replacement interval is 7 years and we are at 12 years. Next, the vibration dampener in the port engine needed to be replaced, something that didn’t get done when we replaced the cracked flywheel housing. (Hmmm, I seem to have skipped writing about the flywheel housing. It’s in my slides for the CAPCA presentation. It’s an interesting story that I’ll need to cover.) We also had a clicking sound in the starboard engine controls that we’d like to investigate.

It started with removing the engines from their compartments. We’ve been hauling out at Jabin’s Yacht Yard in Annapolis. LUX’s 20’2” beam just fits their 21 ft beam 75 ton lift. They have a good crew and a convenient location for us. We disconnected everything from the engines, taking care to label everything. The lift crew then uses the forklift to hoist the engines out of the boat.

We placed the engines under LUX where we could work on them.
Servicing the Engines

Saildrive on its way home for servicing
The saildrives were removed and taken home to be serviced and prepared for installing the new bellows. The prop shafts and seals were checked and serviced so that they wouldn’t leak. The props have to be removed in order to get the saildrives out. It also helped to have someone below the boat, using a screwdriver to pry the external boot open around the bulge at the lower gear assembly. We also replaced the sea water valves since they were original equipment. They were operating correctly, but we've heard numerous stories about various valves on the Leopards. These were the last valves to be replaced.

We cleaned up the engine compartments. While doing gelcoat, we masked the area around the engine mounts and coated the existing green gelcoat with white gelcoat. We also filled in some of the pits in the old gelcoat that tended to collect oil and gunk.

Damaged Vibration Dampener
The old vibration dampeners were definitely damaged, as seen in this photo. Rubber parts were just lying inside. We've collected them in a small pile to the right of the main part of the dampener in this photo. They're black, so they are hard to see against the black tailgate lining. The metal parts tapping each other was probably the source of the metallic clicking sound that we had been hearing from the starboard engine.

New Vibration Dampener

The new vibration dampeners look very nice.

While we had the engines out, we replaced the oil pans. Salt water on the bottom of the pans over the past 12 years was causing pitting and the last thing we needed was to have one spring a leak.

Everything went back together as planned. All the labeling paid off. There were no left over parts and the engines started right up. The clicking noise in the starboard engine is no longer there, and after seeing the vibration dampener damage, we’re confident that it was the source of the noise.