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HOME Maintenance Tips

Maintenance Tips for the Olson 25

As the fleet of existing Olson 25's ages, a number of items need to be watched. Look below for tips on what to watch for and how to fix it.

Note: If you are considering purchasing a used Olson 25, remember that it is one of the best designed and built boats of it's time. I was convinced, the marine surveyor I hired at purchase time was convinced, and so are all of the existing owners. With proper care the boat will last forever.

  • Hull Number

Hull numbers are on the top right corner of the transom within two inches of the deck. The number should read something like PCX0250740585. This means Pacific Boats(PCX) model 025, hull number 074, built in May (05) 1985. There is also Ericson as a builder whose abbreviation is ERY . Hull numbers should be between 1 and about 125. Please checkout the following WebSite for more details on HIN's and a link to the Coast Guard online database to search for manufacturers.

  • Lifting Eye

!!!!!The lifting rod needs to be inspected often for corrosion!!!!!!. Remember the life of your boat depends on it when drysailed

I do not think the lifting eye is available anymore. I assume that they were specially fabricated for the boat. I have seen the following solution for replacing the eye. Find 2 (1 may be enough) large nuts that will fit the threads on the bolt, and take them to a welding shop to be welded together with an eye strap over the top of both of them. Make sure the threads will line up. Then just get a very strong cable to extend the eye up through the deck. Two cables might be safer than one, since the original metal rod is about 3/4 inch in diameter. This link will have to take shock loads as the crane cable may jump on the drum, so size it greater than the weight of the boat. Also, my boat used to bounce when the crane was not operated smoothly.

The stern of the boat will be heavier than the bow. Place extra weight such as sails or outboard motor on the foredeck. Also, use the tails of the two halyard's on the cabintop to hold back the lifting eye. Tie the dead end of the halyards to the lifting ring by the deck opening, then wrap them back around the halyard winches and lock them down tight. This will prevent the lifting eye from breaking the front of the plastic around the vent opening when lifting. If the stern is still too heavy, you need to add extra weight or move weight to the bow to prevent the mast from hitting the lifting crane.

  • The Mast Step

The base of the mast is made of cast aluminum.  Replacements are available from Ballenger Spars.  Stainless bolts hold the mast tube to the base.  Corrosion will occur and the bolts will freeze into the base making it impossible to remove the base without breaking the bolts.  Remove and relubricate these bolts yearly with Lanocote (tm).  Ballenger spars recommends this as the best lubricant for all rig connections.

  • The Mast Vang Bail

Near the base of the mast is the bail used to attach the boom vang. This stainless loop is not sufficient for the loads generated by the Olson 25 main. A number of Bay area owners have upgraded this fitting by replacing it with a bolt-on aluminum tang. This provides an eye for the vang tackle shackle. Removal of this bail requires removing the mast step from the bottom of the mast as the bail is attached with two nuts and bolts. This may be a significant job if the mast step attachment screws are frozen into the mast step. Not to mention having to unstep the mast.

  • The Standing Rigging

See the description under chainplates for details on getting new rigging.  Best method is through the original manufacturer, Ballenger spars.  Remove and relubricate all bolts and screws with Lanocote (tm) as often as possible.

  • The Chainplates
        - Check the aluminum chainplates, contact with the stainless turnbuckles and deck support/flashing and pins causes corrosion and weakening.
         - Also watch out for dry or wet rot in the cabin bulkhead near the ice cooler bins due to water running down through the deck along the chainplate.

In response to the request for information for how to deal with or change the Olson 25 chainplates, I pass on my experiences.  I had a previous boat (Santana 22)with aluminum chainplates.  Boats racing on SF Bay suffered several mast failures within the first 5-7 years.  The two primary causes were broken lowers and corroded aluminum chainplates.  The class immediately instituted a corrective action to increase the size of the lowers from 5/32" to 3/16" and to replace the aluminum chainplate to stainless steel.  After these changes mast failure was almost reduced to nil, if the standing rigging was changed every 10 years.

Because of this experience, I ordered a new set of standing rigging from Ballenger Spars (available as a kit Contact: and some stainless steel stock (rough dimension 30" X3" X ¼") to replace the chainplates.  With a little pre-planning this whole process can be accomplished within a week.  Before you place the rigging order with Ballenger, they will need to know the number of rivets holding the slots for the cable toggles in the mast (not knowing this cost me an extra trip to the boat!).

After dropping the mast, the chainplate can be removed by taking out the six s/s bolts holding it to the bulkheads.  In addition, the "split-pins" located just above and below the deck need to be driven out with a punch.  I found some of the stainless bolts were "frozen" in place, but they were easily persuaded with penetrating oil and an impact tool.  Once removed, I took them to a machine shop and "presto-chango" they created exact duplicates in ½ day.  I used a local marine machine shop (Svenson’s) and found them very accommodating especially when given a little warning.  I did notice that the replacement turnbuckle pins were slightly oversized compared to the originals so it would be wise to give the machine shop the actual pins so they will fit without reaming the holes.  Replacing the chainplates is the reverse of removal (remember there is a left and a right!).  Make sure that the through deck penetrations are caulked with a long lasting elastic bedding compound and seal it all up.  Voila you are done and you should never have to worry about corroded chainplates

PS:  The chainplates on the Olson are pretty beefy and didn’t appear to be approaching failure on my 10 year old boat.  I did see some corrosion around the turnbuckle pins and as mentioned above a couple of s/s bolts were frozen in place.  I highly recommend using a machine shop to make the chainplates because cobalt drill bits are real expensive and there are at least 20 holes to drill!

  • The Rudder

I have replaced the rudder on my boat and want to share with you the process so you can benefit from my experience.

The original rudders for all Olson 25's and 30's (and many popular bay boats like the Santa Cruz 27's) were made by The Foss Company 1332 East Bochard Ave., Santa Ana, CA 92705 949-646-0244 Fossfoam @ aol dot com. The Foss Company still has the original molds and is still producing Olson 25 rudders, more on that later. $725 for new rudder with stainless steel post. $300 if you send in your rudder for a rebuild. (as of Aug '03)

The Olson 25 rudder is constructed of two half shells of fiberglass with a foam core. The shaft is also made of fiberglass with all the fibers running lengthwise. The problem with this construction technique is the seam between the two halves of the rudder, especially along the leading and trailing edges and on top of the rudder. Water seeps into the rudder and causes blistering and separation of the shell from the foam core interior. This is worsened by dry sailing where the rudder is dried and heated in the sun. My rudder was dry sailed and also painted with VC-Tar and VC17m which is dark, so my rudder flexed every day as the sun hit it.

How can you tell if you have a problem? By visual inspection or sounding. When I bought my Olson 25, the marine surveyor used a plastic hammer to "sound" the hull, deck and rudder. I used a similar technique. By tapping your fingernail, or a small metal tool against the rudder you can hear a thunk that changes in tune when a bubble is hit. It is a higher pitched hollow sound. I found a number of bubbles that I could then also see by sighting along the rudder. By tilting the tongue of my trailer down, I could remove the rudder out the bottom of the boat. When I laid it on the asphalt and came back in a few minutes, water was leaking out of the hairline crack along the trailing edge. And this was after about 3 weeks of sitting on the trailer.

I called Moore Boats and they said that they have repaired some Olson 25 rudders before. They pop open the rudder and dry it out in an oven. They replace the foam they can and try to fair out the bubbles. Then they reassemble it with new sealant. Any local fiberglass intensive business should be able to do this for you, but the consensus is that this doesn't always fix the problem and it could run you close to the cost of a new rudder.

I chose the route of getting a new rudder. Don't do this if you are in a hurry. I ordered it through Moore Boats who coated the product from The Foss company with an epoxy coating and faired it. My cost was approximately $600 for the new rudder and $150 for the Moore Boats work (1993 prices). As I recently heard, Moore Boats no longer offers this service, so you will have to order directly from The Foss Company. The Foss Company is a one man shop being run out of a garage, and I never was able to contact anyone there, perhaps I just called at the wrong times. I left messages but did not get a call back. Perhaps mail isbetter. Moore Boats recommends fairing and sealing of the rudder that comes from The Foss Company to avoid any future problems. The rudder will come complete with a new shaft for the above price. You can also send your old rudder in to save some $ and reuse the old shaft. And that brings me to the next problem.

  • Wear on the Rudder Shaft

Olson 25 rudder shafts wear down at the lower fiberglass bearing for two main reasons: all the dirt from the cockpit drains out through the lower rudder bearing, and the shaft appears to be a softer material than the bearing. To solve the draining problem, a number of people have put pipe fittings around the shaft. I found that a standard 4" sewer vent pipe will cover the shaft and slip over the top bearing, and it is very light. The only problem I haven't solved is the lower seal which I can't find a good sealer for. On other boats, I have also seen a large PVC pipe fitting around the shaft on the cockpit floor, just high enough (about 4 inches) to keep out the water. To apply these over the shaft, lower the tongue of the trailer as far as it will go. Remove the tiller and shaft cap. The rudder will fall out of the boat freely now so watch it. Apply the covers and reinsert the rudder.

Another way to avoid the problem is to cut vertical slots out of the bearing on the inside. This provides channels for the dirt to get through the bearing from top to bottom. Also when the shaft turns, any dirt between the bearing surfaces will tend to be caught in the grooves and flushed out. I have not tried this, you are on your own.

The shaft is a tougher problem. Over time, the shaft becomes narrower and wiggles in the bearing. One previous Olson 25 owner actually ground down the shaft and put specially machined metal clamps around the outside of the shaft. These would act as the new bearing surface. I don't like this idea because of the decrease in strength of the shaft (especially the mounting screws!). This also increases the wear on the bearings which will need to be replaced sooner. Bill McGowan of Washington state called me recently and had an idea I like. He sanded down the shaft at the bearing areas and then painted it with multiple coats of "808 vinylester resin." This hard epoxy will make the bearings wear instead of the shaft. Bearings can be replaced by new ones available from Moore Boats 143 Grove St. Watsonville, CA 95076 (408) 763-0196.

  • Bow Pulpit T-weld failure

The bow pulpit on Olson 25's, at least all that I have seen, have a weakness at the forward T weld. This is the weld between the horizontal top bar of the pulpit and the forward stanchion that comes up from the forestay chainplate. The weld will begin rusting and has failed underway on one boat I know. This boats crew was hiking out against the lifelines, as the class rules permit, and the weld broke. Luckily no one went swimming.

I removed my pulpit and took it to a local welding shop that specializes in sailboat hardware. I was very pleased with their work, if you are near Sausalito California, look up Werner's Welding Shop on Marinship Way (415) 332-3230. The shop did a number of things for me. First they rewelded the rusty cracked T weld. Next, they added reinforcing bars on either side of the T forming kind of a V shape when viewed from the foredeck of the boat. They used stainless rod so that I can use the V to clip on my spinnaker turtle if I want. The other thing they did is described below.

  • Bow light

The bow light on Olson 25's is a small bubble fixture in the center of the foredeck. On my boat, the deck sweeping Jib covers it and I feel pretty insecure on busy San Francisco bay at night. Especially with ferry's that go over 20 knots. To solve this problem, I removed the old light and bought a new one to go on the bow pulpit. I covered the hole with a stainless eye fitting similar to a spinnaker pole fitting on the mast. This acts as my missing bow dock line cleat and so far has not caught any important things going past it. I placed a thin aluminum plate under the opening and sealed it into place with epoxy before drilling the new holes for the eye (see below).

I put the new bow light on a bracket welded onto the forward central stanchion of the pulpit. I did this at the same time as the above repair and the whole thing ran me close to $75.00. Prices will vary and so will the quality of the finish after it is done. The heat of welding will tend to tarnish the metal and it needs to be polished, which my welding shop did a great job at. The bracket was made by using the drilling template from the package of the new bow light. I had them place it half way down the stanchion so that it wasn't the most forward part of the boat, and so I could still get my foot under it to step on that tiny part of the bow in front of the forestay. The really tricky part is the angle. I took a string with a weight and tied it to the top of the pulpit at the front. Then using a protractor I measured the angle of the forward stanchion. If the boat is in the water, this makes sure that the new light will be brightest at the horizon. A tiny hole in the bow for the wire, a splice into the existing wires and I was in business.

  • Pulpit mount onto balsa core foredeck

The two rear arms of the bow pulpit attach to the deck of the boat and are bolted through the balsa core deck. After years of flexing, water seeps into the balsa core at the bolts and causes a spongy deck. It also weakens the bow pulpit which is not safe.

I removed my pulpit and went to work fixing things. If the balsa damage is not bad the following ideas may work for you. I enlarged the bolt holes on the outside of the boat and began to dig out the wet balsa core. Placing a bent nail in the chuck of a variable speed drill can help with this. Once you have gotten out as much wood as you want, let the boat dry. Then, I sealed the holes from underneath with tape and poured in epoxy. I got some aluminum backing plates from my welding shop about 2" by 3" and I think 1/8th inch thick. Mixing Epoxy with Micro Balloons from the West System to decrease weight, I made a thick goop. I piled this on top of the backing plates, mushed them up against the deck from inside and taped them up to keep the epoxy from draining out. Once the Epoxy dries, drill the new bolt holes and reassemble with a good sealant to prevent corrosion and leakage into the boat.

  • Knotmeter Replacement

After 2 replacement paddlewheels due to weakness and running into junk in the water, I removed my Signet knotmeter and drilled out the thru-hull hole for a larger KVH thru-hull.  I used a keyhole saw drill bit for drilling doorknob holes in doors.  Hull #74 had pure fiberglass in two areas through the hull in front of the mast.  Clearly intended for thru hulls so they don't penetrate the balsa core. KVH appears to use the same thru-hull as B&G, much stronger than the Signet. But it is larger, so it would be difficult to go back to a smaller one.
 The cabin bulkhead display hole was covered with a plastic plate about 5"x5"(opaque black) and a new hole drilled to mount the new instrument.  Not perfect, but will work for a smaller instrument or different shape display.

Site maintained by Mike Wilkinson if you have comments or suggestions, or contributions.
Copyright © 2005- Mike Wilkinson(14726)



Sailing News

The Canadian Olson 25 Nationals are going to be at Barrie Yacht Club in September 2011.
(click for more info)

The 34rd America's Cup protocol stipulates all new yachts. It will be held in San Francisco Sept 7-22, 2013.
(click for more info)

Yacht Facts

Check out this article on the Olson 25 from Sailing Magazine