Monday, August 31, 2009

Repairing a Maxwell Nilsson VR-700 windlass Part 1

Bianka came with a Maxwell-Nilsson VR-700 electric windlass to help lift and deploy it's 125 feet of chain. Since I do a lot of solo cruising it makes anchoring or weighing anchor easy for a solo sailor without crew. I'd say it is a critical piece of safety equipment if one should find the boat dragging anchor and need to weigh anchor ASAP. I've yet to drag anchor but, it's important not to think that will never happen as you can read here and here. Having the ability to lift anchor rapidly when things get nasty is rather important.

The VR-700 windlass on BIANKA worked very well for years and did not take up a lot of room on deck. It worked flawlessly until one day it failed. Calls to the manufacturers told me that this windlass was no longer made and no parts or parts diagrams were available. Also the companies Maxwell and Nilsson were now separate manufacturers and neither one had any info on my windlass. In fact I had a piece of orphaned equipment on my hands. Not looking good. But, I also was not looking forward to installing a new windlass in the deck for cost reasons but, mostly because that would mean cutting new holes in the deck. So my only option was to try an repair it myself.

The problem was the windlass shaft was still spinning but, the chain gypsy could no longer lift the chain. Not being the most mechanically inclined person I began the investigation into it's failure. The documentation I found on board on the windlass was sparse and had no parts diagram. Basically it was an installation manual that covered several Maxwell-Nilsson models. Because the motor and gearbox is mounted below decks in the chain locker and the Nonsuch mast blocks access to them. I was hoping the failure might be confined to the parts I could work on above deck. It appeared so at first. I could see that the windlass shaft was spinning but the chain gypsy was standing still. So I began by removing the rope capstan and discovered that the key that sits in the shaft was no longer sitting in the key way of the chain gypsy. As shown in the photos below:

This certainly seemed like it was the problem. Pulling off the chain gypsy I soon found why this occurred. It seems the key which appeared to be made of brass had corroded to the point were it would no longer fit securely in the key way of the chain gypsy. Aha! I thought this is surely the problem.

So now all I should have to do is find a replacement key and my chain lifting by hand days should be over. I recalled when I was on a freighter trip several years ago one of the other passengers was an engineer at the Los Alamos laboratories who was also had a hobby of building and repairing small engines known as "hit and miss" engines. He mentioned a supplier of small brass and metal parts by the same name. I looked at their website and yes the could sell me some square brass rod the same size as the key used in the windlass. But, I would have to cut it to the length I wanted. So it looked like the problem with the malfunctioning VR-700 would be quickly solved. Of course this is silly notion when working on mechanical systems on a boat. But, it often gives one the false hope that the repair will simpler than one first thought. But, the lesson learned is that even though equipment on board is working and looks pretty robust it still needs some routine maintenance. If I had looked at the above deck components earlier I could have prevented this failure from occurring in the first place.

Repairing a Maxwell-Nilsson VR-700 windlass Part 2: Removal

So the Maxwell Nilsson VR-700 was repaired rather painlessly including very little pain to my wallet. For about six bucks of square brass key stock I could now lift BIANKA's anchor with the push of a button and also have a lifetime of spare key stock to boot. But, the joy did not last long. I went forward one day to lift the anchor and the Gypsy moved slightly and then stopped. I could still hear the motor below deck turning. This was not good news.
I proceeded to try and find the cause. I pulled off the upper drum and could see that both the chain Gypsy and the shaft were not spinning under load. This could only mean a problem in the gear box below deck. How did this happen? It could have been a clumsy crew member who stepped on one of the deck mounted windlass switches after the chain had been secured to the Sampson Post and because I might have forgotten to switch off the windlass circuit breaker. I know better to NEVER step on these switches but, for the ocassional crew it is an easy thing to forget. Whatever the reason the windlass will have to come out and that can not happen until the end of the season. Until then it's heave away and haul away on the anchor chain. But, it actually got even worse. Sometime that summer BIANKA was hit by lightning directly or by a side strike. The hit did a little damage taking out the heavy duty Pro Mariner battery charger and a few other electrical items. But, it also affected the windlass so that it only operated in one direction. True to Murphy's law of the sea of course that would be in lowering the anchor not raising it. So there are two problems that need to be addressed.


The first issue I had was how to drop the motor and gearbox. I first tried to turn the bolts on the deck plate of the windlass.

I soon realized that they were not going to budge. So it was time to squeeze my six foot two frame into the chain locker. I laid down some old water skiers life jackets that were on board on top of the chain and laid down on my back to look at how to remove the windlass. Strangely I found that being in the chain locker to be somewhat womb-like and cozy. Even conducive to closing ones eyes and taking a nap. But, I had work to do and getting the windlass out was job one. Below is a photo of the VR-700 windlass mounted to the deck. In the background are some of the wiring for the windlass and solenoids that control it's operation.

I don't know whose idea it was to install all this wiring inside the chain locker but, I plan on changing it in the future. I understand the windlass needs to be mounted here but, to have all this other wiring and control relays in there is asking for trouble. The chain locker can be a rather wet and damp environment. Just the kind of conditions for corrosion to take hold as you can see by the bluish hue of the bolts holding the deck deck plate for the windlass in the photo above.

Looking up at the bottom of the windlass I saw three bolts and a mysterious grease spot. Which is a very important clue to maintenance of this windlass and others of a similar design. Below is a what the windlass looks like from below:
I thought there might be a bolt missing and that is why grease was leaking from gear box via the hole. But, I would later find out why the grease was there. Back to removing the windlass. The two electrical lugs on top of the motor were disconnected. Then it was rather easy procedure. Loosening and removing the three bolts on the bottom of the gear box and then sliding the motor and gearbox assembly downward (with a little nudging/tapping from above) it slid out as one assembly.
Below is a photo of the windlass removed from the boat with the shaft.

Now it's time to figure out what the problems are and how to repair them.


So I've removed the VR-700 windlass out of the boat. It has two problems:

1) The shaft does not spin when the windlass is under a load.

2) Following the lightning strike the motor only turns in one direction.

I decide to investigate the motor problem first. The motor has only two electrical terminals on it. At first I assumed one must be ground and the other the positive 12 volt terminal. But, then I wondered how do they get the windlass to reverse direction? Perhaps they reverse the polarity of the terminals. Though that would require some tricky switching to make sure the relay contacts never short out if the did there would be lots of sparks before the breaker tripped. So I hooked up a hefty 12 volt protected power supply to the terminals and then nothing. I reversed them and still no movement. This was puzzling the windlass motor was working in the boat at least in one direction.

I then had a hunch. Suppose the terminals are both 12 volt positive terminals. But, depending on which terminal is energized with the 12 volts determines the direction of the motor. There were no other terminals on the motor so that would mean that the motor case would have to be ground. I touched the ground wire to the case while the positive lead was connected to one of the terminals and motor sprang to life. I moved the positive wire to the other terminal and the motor turned in the opposite direction. My hunch was correct. So now I have confirmed the the motor is working in both directions so the lightning strike had not damaged it. But, the strike might have just damaged one of the solenoids in the windlass circuit. That was something could be easily replaced.

Now it was time to move onto the problem in the gear box. As I have mentioned I'm not well versed in mechanical things. But, perhaps maybe the gearbox problem could be a simple fix. So I opened the top cover:

Yuck! What a mess of grease and gears. So now I start to delve into the gear box myself. I put on some Nitrle disposable gloves and with some heavy duty shop paper towels get most of the dark grimy grease out of the gear box.

I notice the stainless steel shaft is loose in side the gear and see there is what is called a roll pin that goes through the gear then the shaft and to the other side of the gear. This pin is meant to break when the windlass gets under to much strain. Such as when a crew member steps on the deck switch when the chain is wrapped around the Sampson Post. It did it's job and gave me hope that this should be an easy repair. But, when it comes to boats that is sometimes just wishful thinking. As I soon found out.

The problem now became how to get the roll pin out. I first used a punch to try and knock the broken roll pin out. This was only partially successful. I was able to get a piece out but, not the whole pin. The problem is the case of the gear box made me have to use the punch at an angle and was not able to knock the whole pin out. I also noticed that there was actually two pins involved. One smaller pin inside the other. It appears someone previously had repaired the windlass and instead of replacing the defective pin they had simply inserted another smaller roll pin inside the damaged larger pin. It appeared to me that the stainless steel shaft should just lift out once the roll pin was removed but, something was keeping me from removing it completely.

I soon realized that I would have to remove the gear that the shaft stainless steel slid into to make this repair. A fellow Nonsuch owner provided a gearbox diagram of a windlass that he had which is for Nilsson model s400, s600 and s800 windlasses. But, the layout was very similar to my Maxwell-Nilsson VR-700. You can see it here . It help me to see a little more clearly what was involved. The only thing I could see doing was to remove the motor by unscrewing it from the gear case which would also remove the worm gear away from the gear and allow me to remove the shaft and gear from the gear box. So I tried using these:
A number of years ago I bought the largest Sears Arc Pliers I could buy. Mine are about two feet long and the jaws can open up to about 8 inches. I forgot why I bought them but they come in very handy for repair issues like this. I put windlass gearbox in a vice and gripped the motor with these pliers and tried to turn it. I was able to turn the motor slightly and then it stopped. I tried several times with no success. From the diagram it looked like the motor should just unscrew. I was stumped. But, I know enough about mechanics that trying to force things usually ends up being a bad move.

So I go on the Internet and find a little nugget of information that was crucial in a discussion on a cruisers board. It was mentioned almost in passing that a person recalled vaguely that there was a pin that had to be removed to remove the motor. Hmmm, pin holding the motor? There is no such pin on the parts diagram I had. Then I remembered the grease spot on the bottom of the gearbox when I was removing the windlass from the boat. Could it be? I removed the cover of the gear case and put a roll pin punch  into the hole where the grease stain was and with a few taps a roll pin emerged from the bottom of the gears housing.

NOTE: It seems this roll pin secures the motor threads to the gear case to prevent the motor from unscrewing when under load. That is why when I tried to unscrew the motor I could only move it a little. This is a crucial piece of information to remove the motor. With the pin removed I could unscrew the motor and the worm gear and finally remove the gear and shaft from the housing. Now that I can finally remove the gear and shaft from the gear box and I can completly remove the broken roll pin and hopefully get this windlass working again.


So I've found the secret of how to remove the motor from the Maxwell Nilsson VR-700 gearbox housing. It seems these circa 1986 Maxwell-Nilsson windlasses ( and I guess other models) had a roll pin inserted into one of the gear box cover screw hole to lock the threads on the motor so it would not turn and unscrew during operation. Yep, that could ruin your day to have the motor drop into the chain locker! Once this locking roll pin was moved out of the way the motor simply unscrews from the gear box housing (with only a little grunting).

MIKE'S NOTE: When backing out the motor and worm gear there were two spacers on the end of the worm gear shaft make sure you don't lose them and put them back n the shaft when reinstalling the motor.

I did go out and buy an extra tool for this repair and I highly recommend you do too if you don't it already. That is a Roll Pin punch kit. I bought mine at SEARS. But, I expect they are available elsewhere and online.
As you can see in the above photo the Roll Punch has a little nib that helps center the punch in the roll pin. You might be able to use a flat punch. But, the right tool for the right job eh? I figured I may be repairing this windlass again in the future so might as well have the right tool.

You can see in the above photo how the roll pin that locks the motor does it. It simply squeezes up against the threads. This also explains the mysterious grease spot I found on the outside of the gear case in Part 2 when I was removing the windlass from the boat. Some of the grease inside the gear box was able to migrate down though this hole. Grease mystery solved!

When I unscrewed the motor I found some damage to some of the threads. I'm not sure how or when this happened. Maybe someones previous repair attempt or during the lightning strike or because these and similar windlasses made in the eighties used the case as an electrical ground and high currents and the associated heat may have started to melt the threads. I plan to address the last issue when I reassemble the windlass.

With the motor and worm gear removed I was finally able to remove the shaft from the gear that turns it:
You can see in the above photo the jury rigged repair that some had attempted to do by inserting a smaller roll pin inside the original damaged one. It worked ... for awhile.

I then turned my attention to inspecting the gear. On one side things looked pretty good:

But on the other side... It was not a pretty picture:
This side of the gear was pretty torn up by the broken roll pins grinding away when they broke inside. The photo below shows what the gear housing damage looked like when looking at the inside of the gear:

Since I've been told by both Maxwell and Nilsson that there are no spare parts available for this orphaned windlass it limited my options. I figured I've come this far I have nothing to lose. I might as well attempt a repair. Looking at the damaged gear I will have to fill the gap in the damaged side of the gear. Hmmmmm. looks like a job for MARINE TEX GREY. I always carry a box of this stuff on board. It is an epoxy mixture that goes smoothly and is very strong when it sets. It has a compressive strength of 13,000 PSI. Which I think should be good enough for this job. It is good stuff to have around for repairs like this. A few years ago I used it to temporarily repair an exhaust elbow that develop some holes. The repair lasted almost a year. So now I have decided on what to use for the repair. The problem was how am I going to make sure that the new roll pin will line up straight after I use the Marine Tex to fill the damaged gear. Here is what I did:

First I insert a new Roll Pin through the good hole about halfway into the gear as shown above. I coated this Roll Pin with Tef Gel which I have on board for corrosion protection on screws and other hardware. It is also good stuff to have around. In this case I am using it prevent the Marine Tex epoxy from sticking to the Roll Pin. It's a "just in case" precaution.

Below is a shot of how it looks from the the other side of the gear. It looks nicely centered for the repair.

In the next step I take a common nail that will just fit inside the Roll Pin and coat it with Tef Gel too. This will help insure that I will have a straight run though the gear to the other side after I use the Marine Tex for the repair as shown below:
The next step is mix the Marine Tex and work it into the damaged side of the gear carefully without making to much of a mess. Then I will let it cure and slid the Tef Gel coated nail out easily. Then I will drill the Marine Tex side of the gear slightly so the new Roll Pin can be punched through securing the shaft to the gear once again. Like this:
Well that worked out pretty good. Now all that's needed is to insert the shaft into the gear align the gear and shaft holes and punch in a new Roll Pin.
SUCCESS! Well, I might have used a slightly larger drill bit when I drilled the the hole for the new Roll Pin as some of the Marine Tex was snapped off of the surface of the gear when I inserted the Roll Pin but, most of it stayed in place and filled the gap nicely.
So the only thing I need to do now it to reassemble the windlass fill the gearbox with new grease and install it back on the boat.
Finding the grease looked like it might also be a problem at first. In Nilsson windlasses the "Standard lubricant is Castrol “TC” which is a flowing grade 00 grease". I spent the better part of two days making calls trying to find this grease. Nobody in the states seemed to have this Castrol TC 00 grease in anything smaller than five gallon buckets. I then did some Googling for "00" grease and found that Snapper lawnmowers use "00" grease too. So I was able to by a liter bottle of Stens "00" grease for about $11.00 from a nearby lawnmower repair shop. So all in all other than my time the total repair cost (for new Roll Pins, Grease and Marine Tex) to get my Maxwell Nilsson VR-700 windlass working again was about $14.00. Which was not a bad return on my efforts since a new windlass would be a thousand bucks or more. Armed with my new knowledge of how this windlass works and the ability to maintain it it should last another 20 years.

MIKE'S END NOTES: After I had finished making the repair to my VR-700 windlass. The James Nilsson Company began offering some limited parts for their earlier windlasses. It looks like some of these parts will fit the VR-700 and other similar windlasses. You might want to contact them and see if you will be able to fit some the parts they have to your windlass. So far my repaired windlass has worked flawlessly and hope to keep it that way.
Links to previous windlass repair posts: