All posts by jobrasil

Picking a design – Richard Woods Shadow

Yep, she floats!

dscn3048

It was the end of Spring Break 2014. 45 members of the Hoofers Sailing Club and I had just spent 8 days sailing four 40+ft catamarans from Ft Lauderdale to the Bahamas and back. As any good story goes, we were drinking. The next thing I know my mind was made up in finding a the smallest catamaran that I would feel comfortable cruising the Caribbean. Having extensively sailed a 37 ft Catamaran around the world in 2000-2002 I was already sold on the virtues of catamarans. I was looking for something smaller and with a significant smaller cost of ownership.

A large portion of the sailing cruising industry is devoted to selling what I consider the dream of RV camping on the water. I was looking for something closer to car camping… Something funner and cheaper to drive. A boat with a significantly reduced number systems so that any of my friends could sail her without a manual. A fun boat to sail that could safely make headway in a 20 knot trade wind. As my good friend, sailor and awesome boat builder Paul Exner would say: “The Caribbean is no place for a boat that can’t sail upwind in a 25knot breeze!”

I was very excited when I saw a video of Richard Wood’s epic sailing trip. That pretty much sold me on his design and pretty much gave me the confidence that his design choices and tradeoffs would be in line with my needs. I took a good look at his newer designs but Shadow kept calling my name. Safe for coastal cruising, fun to sail, easy to build, trailerable, and good looking! What else could I ask for?shadow

 

Strip or Cold-Molded Hulls?

The original Shadow was designed to be a cold-molded plywood hull. Since then builders have successfully experimented with many different construction techniques. I chose to go with the strip composite method simply because I have experience building smaller boats using this technique. I have a high level of confidence that I can build a fair hull. Price wise I actually think it is about 30% more expensive mostly due to the extra epoxy to sheath the whole hull as opposed to just the bottom.

Note: now that I have finished both stripping and fiberglassing both hulls I can say that I am happy with my choice.

Labor for stripping a hull once you have the frames setup:

I finished each hull in about a month working most weekdays for a couple hours and weekends 6 hours a day. Basically I would set a couple strips in the morning, then a few more after work, and a last batch before calling it a day. Each time I added 1-3 full length strips depending on the placement. You have about 50 strips on each side to add.

Sanding the strips fair 4 hrs a side (you have 4 sides port, stbd, outside, inside)

Filling all the staple holes and gaps between planks 8hrs

Glassing a side 2.5hrs by myself, or 1.5 with help

Recoating the epoxy 1/2 hour a side x 2  coats per side

Filling and fairing the external hull – 3 x 4 hours (2 hours sanding + 2 hours filling)

Cutting Strips

There is no getting around it. If you are building a strip composite boat you need to cut strips, lots of them. For the Shadow I ended up cutting and glueing approximately 500 strips.

It all starts with the best lumber you can find. In my case $2000 worth of clear, vertical grain cedar procured through my local lumber yard, McCormick Lumber in Madison, WI.  A combination of 1×8 and 2×8 of varying lengths from 8-16ft. Mostly 12 footers but since you are staggering the  joints the other sizes come in handy.

cedar uncoveredboard grade

Then set up your table saw as best as you can. It is very helpful to have a very long fence to help you feed the boards. Here I clamp my level to extend my fence. I also found that the Gripper pushblock was a safe and effective way of moving the board through the table saw. My Dewalt DW 745 compact table saw with a 80T fine cross cut blade had more then enough power and made it so that I did not feel like I needed to plane the strips.

table saw

Rollers on the feed side and a plywood box to contain the strip as it comes out. Also notice the shop-vac with a Oneida Dust Deputy Cyclone to help control the dust. The cyclone works great, and very little dust actually gets to the shop-vac. I just had to remember to empty it after every other board since I was generating that much dust.

table saw layout

How much dust you ask? 2 x 30 gallons of fine cedar dust. Just remember to use your dust mask. All of the chemicals that make cedar wood so rot resistant also makes it not so nice for your lungs

saw dust

After milling a 8 inch board, I get 16 – 5/8″ strips and a little bit of waste. The kerf for my saw was 1/8″ and the math adds up. Also since my original boards were surfaced, I have one strip that has rounded edges. I ended up not using the strip with the rounded edges thus getting 15 strips per board. For this boat, I did not bother to bead and cove the strips, since that is unnecessary in the flat sections and in the curves sections a quick pass with a hand planer gave it the appropriate bevel for the strips that needed them.

strips_outcome

It is a tedious process and it took me about 16 hrs to cut all the strips. It goes a little faster with an extra hand. It is critical that the infeed rollers and out feed box are level and square, otherwise the board tends to want to slide out and you will end up with a skinny strip. If you have a power planer and want to mill the strips to an exact thickness that could be helpful, but  I found that my strips were good enough coming straight out of the saw. I ended up with a few skinny strips but the problem seemed mostly to be at tail end of the board, and I just cut out the offending end.

Setting up the frames

Lesson #1 from boat building.

Always do the most accurate and best work you can, so that when you screw up, which you will, it is just not that big of a deal.

Setting up frames starts by drawing them as accurately as you can from the blueprints. Richard Woods has a simple way of drawing his stations and one can easily draw them without lofting the boat. The frames are drawn on 5/8 particle board and cut out as accurately as possible. As part of the design I added a sighting hole and two screw holes that will allow me to place the frames on my strong back as accurately as possible. If you pay close attention you will see that I decided against adding the knuckle on my boat after carefully considering the work and complexity involved.

Frames getting aligned and faired. Notice the lines used to draw the frames

frame setup 1

Back side of frames showing the mounting boards

frame setup 2

View through the sighting hole

frame setup sighting

View of the plywood box strong back. Notice that at this point all frames have been covered in blue masking tape in preparation for stripping.

frame in box

I had a couple frames that ended up a little off. The time to fix it is before you start planking. I found that temporarily adding a shear strip, waterline strip and a center line strip quickly found the offending forms.

 

Stripping the hulls

One by one, as you add your cedar strips to the boat it starts taking form. It is very tempting to rush through this rewarding phase, but we all pay the price later for this. Place each strip as accurately and tight as you can to its neighbor. Wipe all excess glue promptly especially on  the inside. Use as many clamps as you have.

Stripping starts by selecting a place to start. On my first hull I started from the shear towards the keel. On the second I changed that since by the time I got to the bottom of the boat I could not reach inside to clean the excess glue and  check the quality of my joints.

Hull #1 stared at shear line

striiping from shear

Hull #2 started at curved section

stripping curved section first

Stripping goes rather quickly until you have t start closing the gaps. This is the point where the strips will either not want to lay down flat or they have to be tapered to fit.

Measuring the last strip. You can see all the staples holding them in place while the glue dries. Wedges help press the strips in place.

the final strip

Working to close the bow. As many clamps as you have. Notice I had to add a landing piece between the forward frames so that I could land the strips against something.

closing the bow

Details on closing the stern

details on transom taper

The reward. Something that looks like a boat! Here the 1000+ staples have been removed and we started filling the staple wholes and other  cracks between strips that we missed while glueing.

the reward

 

 

 

Preparing the hulls for fiber glassing

Before we can fiber glass a hull we need to do the following:

  • remove all the staples
  • sand and fair the hull
  • fill all the staple holes and visible cracks

This whole process is repeated on the inside once we fiberglass the outside and can pop the hull out of the mold. For the outside it took me about 5x2hour sessions to get the hull where I wanted it. The inside was more tedious since I had to flip the boat over every time I wanted to work on a particular side. Call it 5x3hour sessions

Here you can see the staple holes. I used  Elmers latex based wood filler and that proved to work well. If you don’t fill these cracks and pin holes, they all translate into bubbles as you lay the glass down.

 

filling staple holes

 

Cracks that need to be filled

 

filling cracks

 

Fairing the outside is much easier then the inside. One of my best investments for boat building has been the festool line of sanders with their vacuum cleaners. These sander worked as advertised and the dust inside the garage was minimal. For the outside the  ETS 150/5 EQ Random Orbital Finish Sander with 80 grit sandpaper worked great.

bow details

The inside can be a real challenge if you did not clean the glue as you stripped. We started by trying to work under the boat. We quickly realized this wasn’t healthy… For sanding the interior, another festool sander came to the rescue. Rotex RO 90 DX Multi-Mode Sander. With its small profile, light weight and polishing soft pad it did a great job of cleaning and smoothing the insidie radius.

fairing the interios

Working on the inside got a lot easier once we figure out that once the outside was fiberglassed we could rotate the hull safely by adding a few cross braces

 

hull on its side

 

Fiberglassing the hulls

Time for a little commitment. Fiberglassing is not a difficult process but preparation is key. I’ll fill in the details later, but here are some pictures

Glass ready to epoxied. Use a little blue masking tape to hold the curling edges in place.

glassing inside of hull

 

Glass saturated in epoxy after first coat

glasssed inside of hull

Here is the hull after two coats of epoxy plus the third with a fairing filler to fill in some of the deep gaps in the biaxial glass

hull after 2coats

 

Popping the hull out of the mold once the outside glassing is done and rotating it to work on the interior. Notice the straps are braced against the temporary spacer boards to prevent the hull from being crushed.

lifting and rotating outside glassed

Ok so we are ready to glass (these instructions are based on west system epoxy and fast hardener)

1) Pick the right day – The perfect day is  about 70 -80 degrees,  low humidity, slight breeze. If it was a cold night you will have to wait till the day warms up. Never work uncovered where the dew can settle on the boat at night. Remember you will need to have three coats of epoxy before you can get a good night sleep.

2) Vacuum and dust your shop as best as you can

3) Make sure you have plenty of containers to mix your epoxy. I was using 20 pumps at a time. Avoid reusing mixing containers to prolong pot life

4) Also have at least two paint trays and two rollers handy. If you work a little slower you will need a third roller

5) If you can have someone just pumping and mixing it is of great help

6) Layout your glass carefully and avoid kinks or folds

7) Use small pieces of masking tape to hold the glass in place

8) Have an ample supply of gloves available

9) Make sure you have at least one gallon of epoxy per side. 4 gallons a hull.

10) A glass roller is your best friend

11) Have some rags and a a spray bottle with water and vinegar for minor clean ups

I started by applying epoxy 2/3 back working towards the back and then the front. This gave me about the right time to keep a wet edge and keep the glass in place. With a third person You can basically start in the middle and work your way out. For more details My reference book is Epoxy Basics with a variation for dealing with the 12oz biaxial. I found it almost impossible to get rid of a large number of bubbles unless I used a fiberglass roller. I did one side by myself and it took 2.5 hrs for the initial glass work. The second side, with two helpers, just under an hour and a half.

 

Making the keel

I really could not figure out a better way of doing this, but any suggestions are appreciated

So this is how I went about it

1) Lofted the dimensions onto the boat itself. Luckily I used one of my strips to mark the center line…

keel lofting

 

Then I used some hot glue to bond a cedar strip in place. I did this because I want to build the keels off the boat and bond them in place later.

keel hot glueing

 

The finally after epoxying another strip on top I planed the surface flat to receive the first board.

 

keel 1st layer

Now I go ahead and glue all the pieces together. Make sure you very carefully tape around the keel so you don’t accidentally glue the keel to the boat at this time. If your boat is parallel to the water line, this is a good time to make sure the bottom of your keel is also flat and level. Adjust you keel bulkheads as needed.

building_the_keel

Now with all the internal pieces in place and epoxy coatedkeel ready to be closed

 

Sheathing with plywood

keel adding plywood sides

 

 

Adding the external stripskeel adding external strips

 

 

Ready for shaping then fiberglassing.keel ready for final shaping

 

Faired and ready to glass

keel shaped

 

Building the cradle

I am getting ready to move the boat to a nice heated garage over the winter. I decided that I would attach the keels after decking the boat to make it easier to work on the interior. That has the additional benefit of  making the cradle much easier to built.

The bottoms are 2×12 – 4ft
The sides 2×8 – 8ft
4 metal corner brackets hold it together.

I used frames 3 1/2 and 7 + 15mm offset to get the profile for the bunkers.

cradle fit cradle brackets cradle

 

Winter building space

I spent the last couple weekends moving the boat and tools into the “Boat Barn.” I just started working towards installing the bulkheads and took some more notes and pictures.

Here is a picture of why you want to fill all the staple holes. You can see an air bubble that made its way to the surface. These bubbles allow a direct path for the water to seep into the hull. Fixing them is not hard, but not having them to begin with is better.

airbubble

 

Here is a better picture of how the biaxial glass lays down and the filling required to sand it smooth. I wonder if adding a very light woven cloth as the top layer would make fairing easier.

filling the weave

At this point I decided to sand all of the interior surfaces to 80 grit to simplify bonding the bulkheads. At first I thought I would only sand where needed, but decided to just prep the whole interior surface.

hull from behind

Bulkheads cut and in place

bulkheads in place

Ooops! this what happens when you read a 3 when it is supposed to be an 8. Bulkhead #4 off by 50mm in height. Notice the low shear corner…

bulkhead goof