Welcome to a blog for Mona Risa - Wharram Tiki 21 #924. Telling the story of a full rebuild and, hopefully, the further adventures.
Mona Risa stayed in storage for several months. Upheavals in my personal life got me to pondering what I wanted to do with my boating life. I knew that I would be working full-time for the foreseeable future. Which wouldn’t leave much time for a boat that required a lot of assembly/disassembly time. Even if I avoided assembly time by renting a marina slip, it seemed like a waste to keep a fast boat on a small lake that could only be sailed a few months out of the year.
I trailered Mona Risa out to the ramp at the Jo Bonner campground on Canyon Ferry. It’s a low traffic, shallow ramp with some shade. It’s the same place that Rich and I assembled the original boat that I pulled back from Canada.
I had originally used commercial carpet to cover the trailer bunks, but I noticed that it was retaining moisture and leaving dark smudges on the paint. So I ripped off all of that carpet and recovered all the bunks and braces with actual bunk carpet. That seemed to work much better!
With the mast up it was time to finalize the running rigging. I had been thinking about the rigging for a few years and was ready to try out what I had come up with.
On my previous boat, a MacGregor 22, I could raise the mast singlehanded without any mechanical assistance. I was hoping to do the same again, but after trying brute force I realized that the boat layout was working against me. In the MacGregor I could stand right at the stern of the boat, grab the mast and lift and walk forward to the mast base. Since the Tiki doesn’t have a deck all the way to the stern I had to start my lifting much lower down on the mast where the leverage was working against me. I needed some kind of engineered solution.
In Standing Rigging - Part 1 (2.5 years ago!), I left the shrouds and forestay with big loops spliced in the top ends for the masthead, but I didn’t splice thimbles into the lower ends. Since I had changed the height of the mast I wanted to size the standing rigging with the mast in place. I thought an actual measurement would be better than trusting my trigonomery skills to modify the rigging sizes in the plans.
Rachel and I moved the hulls out of the garage and onto the patio using some scrap metal roofing to roll across the gravel and grass. It was great see her out in the sun! And the boat, too LOL
With the hard parts of the boat completed I wanted to weight the parts so that I would know how much weight I was putting on the trailer. I used a scale hanging from the rafters in the garage with some 2x4s for support when weighing the hulls. I checked for accuracy using my body weight and a bathroom scale.
I love these low-tech Wharram innovations! If you’ve read Two Girls Two Catamarans you know that James had rudder hardware problems on his first two transatlantics so he was motivated to find better rudder attachments. He came up with rudder lashings that eliminate hardware and are easy to inspect and service.
With painting all done and thinking about assembly, I wanted to protect the surfaces between the decks and beams that would rub together. I also knew from past experience that the rubbing also makes a lot of noise. So I plugged some vague search terms into my favorite search engine and came across UHMW-PE tape (ultra-high molecular weight polyethylene). It’s used as rub strips on conveyor belts and used in automobiles to quiet pieces that rub together. Sounds great!
Moving right along it was time to install the windows and portholes into the cabins. I installed the rear windows with butyl tape bedding and stainless steel hardware. I tightened up the bolts over a few days and kept squeezing out more sealant. Once I thought I had a good seat I trimmed off the excess butyl tape inside and out.
When the paint had cured for a few days I put a couple of coats of wax on the parts of the decks and cabins that weren’t non-skid. Then I got to work on finishing things up.
I had primed earlier, so painting the decks and cabins was quick and easy. I put on four coats of paint and stopped before the fifth because I was worried about filling in too much of the non-skid texture.
I started painting the bottoms by applying lightly sanding the last epoxy coat and then applying two coats of primer.
After getting the keel protected, it was time to finish filling in the weave on the rest of the hulls. I had purposely stopped short of completely filling in the weave when I originally glassed the hulls. I knew that while working on the decks I would foul the hulls with some epoxy drips and splashes so I held off on the final epoxy coats.
I coated the keels with graphite to add some protection but also wanted to add something more substantial. The Wharram plans call for a metal strip on the keel and skeg. It is also common to glue a strip of sacrificial hardwood to the keel onto the fiberglass.
With the hulls flipped, the first task was to put fillets along the joint where the sheerstringers meet the hulls. That joint is where the fiberglass from the decks met the fiberglass covering the hulls. I sanded the joint to take care of some rough fiberglass edges and then put in the fillets.
What a thrill to actually put some paint on the hulls!! Even if it was only primer. I prepped the cabin sides with light sanding, but didn’t put any sandpaper to the nonskid on the decks. I washed everything well with hot water and vinegar to remove any amine blush. And then I rolled on a latex primer and was happy with coverage after two coats. I masked off the beam sockets and the tops of the “luggage racks” so that I can glue on some rubber pads there later.
Five months ago I finished glassing the decks and cabins and thought that I just had a few little things left to do before I was ready for painting. Was I wrong! So, it’s taken a while but now I’m back to finishing the glassing job. It’s time to put on the final coats of epoxy to fill the weave and to apply the nonskid texture to the decks.
Before I finished the epoxy on the cabins I wanted to drill all the holes needed to mount the ports and windows on the cabins. The original hulls came with some opening port holes. I am reusing them in the fore part of the cabins hoping to get air flow from fore to aft. I also had some plexiglass cut last year to mount in the aft part of the cabins for a view out when inside.
As I mentioned the first time I built the gaff, I thought I would need to rebuild it. Being made of ash, it is quite heavy and the springback after bending made it fit around the mast poorly. So lamination to the rescue!
I needed to modify the tiller bar that I built previously because the newest tillers had more curvature to them and were thus closer together at the ends. The new tiller pins were located about 2” inboard of the previous holes.
I needed to replace the tillers that I had re-built for the original boat. The original rudders had a rudder head thicker than the plans called for - three pieces of 3/4” plywood laminated together - and I built the tillers to fit over that. Because I built the new rudders to plans, the new rudder heads were only 5/8” thick. So the base of the tillers would need to be much narrower to fit them. I also wasn’t happy with the curvature in the rebuilt tillers as they had snapped back some after glue-up. So let’s build them again!
I’ve been working in the basement to touch up and then recoat the bottoms of all the platforms and the beams. I primed all the fresh epoxy first and added several coats of orange with a small foam roller.
Last year I placed thickened epoxy in the rudders and stern posts for the rudder lashings. Now it was time to drill into those spots for the rudder lashings. I ordered some 2.5mm Dyneema line for the lashings and made a template for drilling. It was easy to drill the holes in the rudders using the template and the drill press. However, it was harder to get plumb and level holes in the stern posts. I made a guide stick that I could lash to the stern posts and then level and plumb as needed. I used the stick as a visual guide for the drill bit and the results were pretty good.
It was time to figure out some of the running rigging so I could install cleats and hardware before painting. I started with the hardwood cleats on the beams. I installed them in 2017 finished clear with varnish and no epoxy - that didn’t last at all. So I removed all the cleats and gave them three coats of epoxy. I also added wooden anchor cleats to the fore and aft beams on the inboard side of the hulls. All the wooden cleats were reinstalled with butyl tape and thread locker and were then painted.
Flash back to 2017 to see when I first built the platforms for the original hulls and the original beams. Those hulls were shaped a little differently along the side of the cabin where they meet the side platforms. The old beams were even more different than the current ones because they had no fillets on them.
With the fiberglass on the coamings, it was time to install the fasteners for the main hatches. I installed the fabric side of the Lift the Dot fasteners into the hem of the hatch covers. It was a slow process with a punch and an Exacto knife but the offical tool is $80 - ha! On the coaming, I marked and overdrilled the holes and filled them with thickened epoxy.
The Tiki plans call for a combination of swivels and securing blocks to hold the platforms in place. After experience with the Tiki 21 in Ghana I wanted to try something different. Instead I added blocks to the struts on the beams to hold the platforms down from the fore and aft ends instead of the sides. I was able to use the same design for the center and side platforms and the fore platform as well.
I decided to add “luggage racks” to the rear decks. I thought it would be a great place to store gasoline and propane tanks. I know rear netting is common but decided to try this instead. The ash cleats are glued and screwed in place with some big fillets around them as well.
The tilt mechanism on my outboard is designed for a sloped transom and won’t raise the motor very far out of the water when it’s on the vertical transom of the Tiki’s center platform. So I attached a rubber V block to the underside of the aft beam and a clam cleat above it. I’ll be able to use a short line to snug the bottom of the motor up against the rubber block.
I made jib sheet leads 2’ long in ash. I glued and bolted them to the cabin sides with 5/8” backing pads. I filleted inside and out.
With the beams fitted I could mark on the cabin sides where the ledges for the side platforms would be located. I beveled the top edges of the ledges for good support for the platforms. Wire stitches helped get the placement correct and screws from the inside clamped it tight. Cosmetic fillets covered up the wire holes.
Ugh. I had a long, rough time getting the beam pads and sockets properly constructed. I started by leveling the hulls with shims under the hull cradle wheels. Then I leveled the beams in their spots with a line level.
Hey - I’ve done this before - and before! I created new beam cleats out of ash and attached them with epoxy and a couple of screws. After curing, I removed the screws and added three 1/4” bolts to each cleat. I then added cosmetic fillets around the outside of each cleat. I also added a bigger fillet inside the cabin above each cleat at the hull/deck joint.
Before leaving for Ghana I started using a small propane tank top heater to cure epoxy. At the time, I was working in a less finished and less insulated garage so I had decided not to heat the whole garage. Instead I built a tarp tent around my work and put the the heater in there. It was a pain.
I glued and screwed the trampoline battens to the fore decks after drilling the lacing holes to fit the trampolines included with the original boat. To finish, I added cosmetic fillets and filled the screw holes. I realized the day after glue-up that I should have made the battens out of hard wood. Doh! Hopefully I will get a few years out of these before I have to replace them. I also used softwood battens on the fore platform when I built it a couple of years ago, so I guess I will be replacing all of them at the same time.
With the decks glassed, I started attaching fittings to the decks beginning with the fore hatch. I glued and screwed on the deck half of the rope hinge and a hold down for webbing made of ash. I finished up with cosmetic fillets and epoxy coats.
I left Mona Risa in storage while I traveled to Ghana for the 2018-2019 winter. Once back in Helena I had some other priorities before boat work - marriage and then fixing up the garage and yard at my bride’s house. The remodeled garage is a great boat shop and I also created a pad to park the boat trailer on when stored. But, unfortunately, all that work pushed boatbuilding back until September. Now the rush is on to beat the cold temps while working in an unheated garage.
Sailors are superstitious and generally reluctant to rename their boats. But, with libations to King Neptune and the proper ceremony it can be done. Just remember to never mention the boat’s previous name again!
I’m not presumptuous enough to think that I have discovered some unknown tricks for working with epoxy. I just want to gather in one place a few things I have learned from others. Maybe just so that I don’t forget them! For more great epoxy tips, see:
With my boat stored for the winter, I took a volunteer position at Escape 3 Points in Ghana. I spent several months there working on a Tiki 21. The eco-lodge is on a gorgeous part of the western coast of Ghana. It’s remote and quiet and has a great beach.
Winter was making it too difficult to keep working with epoxy in an unheated and uninsulated garage so it was time to put the boat away for a few months. Friends helped me flip the boat and load it onto the trailer. This was the first time that these hulls had been on the trailer. I was happy to see that the bunks fit the hulls just right.
After getting the fiberglass glued down, I went back and added two more coats of epoxy with a foam roller and chip brush. Next I wanted to coat the keels and skegs with a few coats of graphite. Graphite gives a slippery surface that is supposed to be good at taking bumps. I wanted to give it a try instead of paint.
Since the first hull side went so well I tackled the next three hullsides quickly. Once again I overlapped the keel and skeg so that the bottom would be well protected. The final overlap will be on the inside of the hull (when they are upright) so that the outside will have a smoother appearance.
Honestly, I was intimidated to fiberglass 21 feet of hull in one go. But I had done smaller jobs on Super Chicken and I had seen a few videos so it was time to give it a go. The weather at this time was a blessing and a curse. It was cold so I would have a long open time when working. But it was too cold to cure so I had to construct a tent inside the garage with a heater inside to raise the temperature for curing. The tent made work difficult because the light was poor inside.
I took the belt sander to the keel to clean up drips and wire marks, but I tried to remove as little actual keel material as possible. I faired from bow to stern with my fillet mixture. It took a couple of fairing sessions but I ended up with something that the biaxial fiberglass tape would wrap around smoothly. I applied the tape from the bow waterline to the skeg.
I gather that it’s a momentous day in a build to flip the hulls. And it sure felt like progress to me! The actual flipping was quick and easy. I laid the hulls on their sides on some tires while I removed the cradles. And with just a few shims, I was able to reuse the wheeled cradles with the hulls in the upside down position. Thanks to a few friends for helping!
Before I started the rudders I marked where the rudder lashings would fall on the sterns. And then chiseled out the wood where the lashings would pass through and filled with thickened epoxy. The lashings were the entry points for water on the original hulls and I didn’t want to have that problem again.
The platforms I built the previous summer had spent a few months in the sun while being stored on the trailer. And the epoxy finish had checked badly. I thought the UV-stable epoxy from Duckworks had failed. But some research told me that Douglas Fir plywood always checks and should be covered in fiberglass.
Before I put on the cabin tops I did some finish work inside to make them cozier for living. I wanted a nice finish inside that was easy to keep clean. The inside of the hulls already had two coats of epoxy on them but the epoxy coat had been abused while wiring the hulls together and adding the fillets and bunks. I cleaned up drips and fillet chunks and did a light sanding before rolling on a thin third coat of epoxy. It turned out very nice.
The main hatch coamings were built according to plans, but using 3/8” ply and 3/4” stock. I also added rails to the insides of the coamings to support the soft hatch battens and a soft seat.
My first step in adding the cabin tops was to add a small shim to the center bulkhead. For some reason, the center bulkhead was a little short in both hulls when using a straight edge from front to back. So adding the shim would prevent a sag in the top.
Measuring and cutting the cabin sides was a little tricky. I knew there would be some variations from the measurements in the plans because my sheerstringers were 3/4” instead of 1/2”. The thicker sheerstringer would change the height of the cabin sides a little in order to fill the gap at the bottom. I used ratchet straps and wedges to hold the plywood for marking in place. This worked and the cabin sides fit well.
I generally followed the building plans for the coamings and hatches for the bow lockers. My differences were: 3/4” stock instead of 1/2” stock, 3/8” plywood for the coamings instead of 1/4”, and the fore and aft blocking I had added to the inside of the deck made the coamings very easy to attach.
The fore decks used the same process as the rear decks - cut mortises in stringers to fit bulkheads, attach center stringer, mark lateral stringers, and glue laterals.
Once again, I did not use the triangular wood called for in the plans. For the deck stringers, I used rectangular pieces that I milled from light-weight spruce. The dimensions were inspired by Rod’s Mana. I also cut the rear decks in one piece instead of two pieces joined down the middle as called for in the plans.
With the hull fillets done, it was time to add the bunks. The building instructions call for drawing the hulls to full-size to measure the bunks correctly. I decided to just measure using scraps of cardboard and tape and some trial and error. It worked fine.
I quickly got into a rhythm on the hull fillets. For each hull section, I would prep by sanding and cleaning, aligning the hull, and cutting the fiberglass tape. Then I could do all the filleting and taping for a section in a couple of hours. I applied the fillet mixture out of the cut-off corner of a plastic bag. And then smoothed to the proper radius with tools cut from plastic auto body repair scrapers. I laid the fiberglass tape in the wet fillet and then smoothed with a dry foam roller and filled with neat epoxy using a chip brush.
I spent some time stringing lines and checking the alignment of the hulls. They didn’t line up perfectly, but with nudges and twists on the wires I could get things lined up. I checked my alignment before I started filleting each hull section and the hulls turned out straight.
I stole an idea from Rod’s Mana 24 and built my own inspection hatch covers for the bows and sterns. I had saved the 9” round plastic screw-in hatches from the original boat, but after I saw this design I knew it would work better than the plastic ones - which were already breaking and missing O-rings. I built the gaskets out of old bicycle tubes glued together with contact cement.
In mid-July 2018, I went to Lake Diefenbaker, Saskatchewan, Canada to sail with my friend Rod on his Mana 24. We became friends on Facebook via the Wharram groups because we were both working on Wharrams at the same time. Rod had also built a Tiki 21 in the past so I was curious to sail on his new boat and talk about his old boat. Remember, at this point I have never sailed on a Wharram! My only catamaran experience is a small Hobie cat in college.
With the hulls together, the next step was adding diagonal stiffeners and backing pads for the forebeam cleats and shrouds. The plans call for triangular stock or round stock. I didn’t want to mill triangular stock and couldn’t find half-round in the right size so I went with rectangular stock. I imagined that there was a chance water could collect on the upper joint along the stiffeners so I put a fillet along all the top joints. When gluing I used some sacrificial blocks to keep the wires from biting into the stiffeners.
After a break for summer fun, I got back to work on the second hull. I glued the hull sides, added sheerstringers, coated the hullsides and bulkheads, and wired all together. It went so fast that I hardly took any pictures!
The building plans give a specific order for wiring in the bulkheads. I followed that order. It was difficult to get a bulkhead aligned and tightened the first time. The best technique was to insert a bulkhead loosely and then insert the next bulkhead before going back and aligning and tightening the first. There was a lot of tension in the hull sides that wanted to shoot the bulkheads up so it was important to angle the wires for a downwards pull. The stern was hard to pull together and required pipe clamps and patience. But in the end everything aligned correctly.
The building plans give explicit instructions on wiring the hulls together. I deviated from them a little bit because I was using 3/4” material for the keel instead of 5/8”. Otherwise, I followed them exactly and was very happy with the results. It’s starting to look like a boat already!!
The plans call for adding the deck beams to the bulkheads before putting them into the hulls. I decided to also add the bunk bearers at the same time. It seemed like it would be a lot easier with them out of the hull. I coated both sides of the bulkheads with two coats of pigmented epoxy.
I tried something new to me when coating the insides of the hulls and the bulkheads with epoxy. I wanted a lighter feel inside without painting so I added some white pigment to the epoxy resin. I used 4 ounces of pigment per gallon of epoxy. The effect is really subtle but increases with each coat. I was really happy with the outcome. Though the effect is subtle it’s very easy to tell the difference between pigment coated plywood and plywood coated without pigment. The ply without pigment is much darker.
With the pieces cut, it was time to glue the hull sides together. Each hull is made of three pieces joined by butt blocks at the joints. I glued the pieces together with thickened epoxy trying to keep them as straight as possible along the top edge. Of course, each piece of plywood had its own twists and bows that made this difficult to align and to hold while the epoxy cured. I added the sheerstringers afterwards along the top edge of each the four hull sides.
Once my 1/4” marine plywood arrived I set to work cutting the pieces for the hull sides, butt blocks, and bulkheads. I did a lot of tedious measuring and re-measuring before cutting the first pieces. And then used those pieces as templates for the rest of the hull sides. Afterwards, I clamped the pieces together and used a belt sander to make them uniform. Same story with the bulkheads. It was hard to cut the holes in the bullheads and end up with a perfect circle, but it was pretty close.
I had a burst of enthusiasm after making the decision to rebuild the hulls. So I didn’t wait for the marine plywood order to arrive. I bought some 3/4” ash and started milling parts for the sheerstringers, keels, sheerstringer doublers, beam cleats, and beam blocks. I scarfed shorter pieces together for the sheerstringers and keels. The building plans call for two different kinds of scarfs for these pieces as you can see in the photos.
At this point in the rebuild, I have become very familiar with the Tiki 21 plans. And I have spent a lot of time crawling around in the hulls. And I have started to have some serious concerns:
The beam lashing cleats on the hulls showed a lot of rot and weakness around the edges. The cleats were made of plywood and the edges had not been sealed very well. In addition, the cleats for the front beam had not been bolted at all, but attached with screws. The buried screw heads had allowed moisture into the plywood. Also the cleats had not been epoxied to the hulls. I believe they were attached with 3M 5200. Going around the hulls I could pull some of the cleats off with just my hands!
The main hatches that came with the boat needed a lot of repair work or needed to be rebuilt. Also, the more I used the hatches the more I disliked the original design. So I set about looking for what others had done. I found one-piece hatches that slid forward on rails. I liked that - except for the rails across the cabin top. I also liked hatches that opened outward on rope hinges. Usually they had a strut or stick to prop them open. I liked that design too, but it didn’t allow for partial opening.
While the temperature was too cold for epoxy work out in the garage, I did some sewing. I wanted sail covers to protect the sails while anchored out. My mainsail does not have a zippered luff so there was no way to stow it while at anchor. I made the sail covers out of nylon and used webbing and buckles for the closures instead of zippers.
The fore hatches on the boat had not been covered in fiberglass. That’s according to the building plans. However, the wood had checked badly and the paint cracked. I sanded the hatches down and glassed them. To make fiberglassing easier, I would have liked to use a router to roll the edges and corners more. But the thickness of the wood used prevented that. Bending the fiberglass around the corners was a little difficult but came out OK.
The trailer that came with my boat was a small tilt-bed trailer probably originally used for a small flat-bottomed john boat. The 10 foot long trailer bed means that the boat overhangs the trailer front and back it but seems to make it easy to launch and retrieve the boat. The way that the boat builder had adapted the trailer for a Tiki did not support the hulls individually. Instead it required the use of “travel beams” to connect the hulls together for stability. The hulls sat on wooden frames on the trailer. Launch and retrieval was difficult. It entailed a little ballet on the water to change from the travel beams to the real beams without upsetting either hull. I didn’t like it. And, after one launch and retrieval, thought that it would be impossible to do by myself.
The original rigging that came with the boat was stainless wire rope with with pressed-on fittings. There was a lot of rust on the fittings, but otherwise it seemed ok. However, I have an innate distrust of wire rope fittings - you can’t see the condition of the wire rope inside the fitting. I had also decided to make the mast 18” longer than the original so I probably needed new rigging instead of just extending all the lanyards.
The original mast was a 20’ long aluminum pipe with a wooden head and wooden foot. The Wharram plans call for a 21’ 6” mast. The original mast was 22’ 6”. The head was already rotting on top. And, the distribution of the wood was weird to me - the foot was a short stub and most of the length of wood was on top. That led to a top heavy mast. I decided to rebuild the mast to 23’ with a short head and a taller foot to get the weight on the bottom. I also wanted a little taller mast to give visibility under the main sail - at least when the wind was light.
I really did not want to rebuild the beams. I really tried to talk myself out of it! But it didn’t work when I started listing the problems:
The original gaff was in bad shape and I decided to rebuild it while I was working on the tillers. Since I was planning to sell my house and cruise full-time, my logic was that this was my best chance to rebuild some of the pieces and parts - while I had a workshop. So I added the gaff to the list.
I had broken one of the tillers and decided to rebuild them both as I had noticed that the bend in the tillers was not as curved as the plans call for. I used some clear pine and DWX epoxy so that I could finish them clear. Using the instructions in the plans I used weights to bend the tillers while gluing. I wish now that I had used a jig screwed to a piece of ply. I also wish that I had overbent the tillers a little. There was some snapback that decreased the curvature in the tillers.
In January, 2017 I “retired” from computer work. My plan was to get my house ready to sell or rent and then spend the summer on the boat. Of course, work on the house took longer than I thought and I hadn’t finished house work until August. Where does summer go?!
In June, 2016 I drove from Helena, Montana, USA to Bobcaygeon, Ontario, Canada to pick up my pre-owned Wharram Tiki 21. I was very excited to get my new boat and to see some parts of the world that I hadn’t seen before - the Upper Peninsula of Michigan and the North Channel of Lake Huron (a famous cruising area). Unfortunately, I didn’t have much time off from work to spend time in these areas so it was just a quick drive through and back - 4,400 miles in 7 days. Ugh.
This boat story has all the elements of a drama: high hopes, chicanery, desperation, and triumph (hopefully). This is the story of falling in love with a boat design, finding that boat in Canada, bringing it home to watch it fall apart before rebuilding it in the USA. This is the story of a boat named Mona Risa.
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