The building and launch of “Crwban” a 10′ Herreshoff Pram.

With the Covid-19 pandemic breaking out, it seemed as if “Social Distancing” by building a boat would be a good idea. I have always admired the Herreshoff Pram design in John Gardner’s “Building Classic Small Craft” book. I thought I could build her light enough to car-top and she would be big enough for two . I began to build “Crwban” a 10′ Herreshoff Pram on March 29th, 2020.

I will build her using the Glued-Lap method. I will use light ribbands to determine the plank lines. In the book, the plans have suggested plank widths at three of the stations.

Herreshoff Pram build

My first step was to build a building frame for the station molds. I picked through a lot of 2 by 4s to get two relatively straight ones.

A crosspiece for each station mold. Trying to keep the base as “square” as possible.

Herreshoff Pram build

The legs for the base are repurposed pieces from a futon frame.

Herreshoff Pram build

The building frame is complete and as “square” as I can make it.

Laying out the station molds

I have gotten a deal on some chipboard. I am laying the molds out on them. I am cutting the chipboards down to the mold size.

White shows the pencil lines better

Laying out the molds onto the chipboard is hard, so I paint the boards white so the lines will show better and it is also a better surface to draw on.

Drawing the lines

Here I am drawing the lines for the mold. I am using a flexible piece of oak strip to draw the outside mold line. I will be building the boat upside down and have adjusted all of the measurements for this.

Bow transom glue-up

I recently acquired some walnut flooring. I mill the flooring pieces and glue them together getting a 1/2″+ bow and stern transom.

Stern transom glue-up

I am using Titebond II to glue-up the transoms.

Cutting out the station molds

I cut all of the station molds out using my jig saw.

Rough cut on the molds

With the molds rough-cut out, I will use my disk sander to fair the curves.

Fairing the curve on the bow transom template

I sand the molds and the bow and stern templates to get a fair and even curve.

Setting up the station mold and the bow and stern transom templates.

This is the most finically part of the process. The pieces are held in by screws to the cross members. I can adjust the height and sideways placement until all the marks line up. I then clamp everything up. Double check the alignments, then, screw it all together.

Stern transom

I am fitting the stern transom for a rough cut to shape…Final shaping will be when the planks are laid.

Bow transom rough shaping

Getting everything roughed out and aligned.

Cutting out the transoms

I use my 14″ bandsaw to cut out the transoms.

Bow transom
Stern transom

With the transoms roughed out, I begin to put the ribbands on.

Yellow cedar ribbands.

I am going to use the ribbands to determine the plank shapes.

Fitting the ribbands.

The plans have plank widths for station #8, station #3 and the stern transom. I cut notches in stations #8 & #3 for the ribbands.

Eyeballing the planks

This is another finically operation. Put the ribband onto the molds, have a look and see if the plank outlines look good…maybe adjust one which makes you adjust another…and so on.

Half done

When I am satisfied, I duplicate the measurements to the other side.

All the ribbands fitted and faired. Time to “lock them down”. A dab of epoxy will keep them from moving. I have to remove all of the finishing nail to lay the planks.

I decide to take the ribbands to the transoms. I will trim off all of these ends.

Epoxy holding the ribbands to the bow transom form.

I lock all of the ribbands down with epoxy and remove all of the finishing nails.

Ends trimmed

I have trimmed off all of the ribband ends and the bow transom will be rough cut and have its final shaping when the planking goes on.

Bow transom roughed out and ready for planking

The bow transom is ready to start planking. The wide notch is for the garboard plank…I decided to do a plank keel instead of two planks with a keel piece.

Stern transom ready for planking

It was my intention to use that stiff floor protector construction cardboard (Ramboard) stuff to get a pattern for the planks. Place a strip along the ribbands, draw to the outside of the ribbands. Presto! a plank pattern.

Sadly, due to the Covid-19 pandemic, my supplier of floor protector is closed and Ramboard is out of my budget. After a lot of thought, trial and error I develop an alternate plan.

Bevelling jig on the 12″ disk sander.

I am going to cut all of my plywood into strips, splice them together to get planks and then lay the planks onto the form to get the plank shapes. To quote John Gardner: “Fortunately, our pram has an easy shape to plank. Strakes can be lined out nearly straight, for the greater part, and go on without twist or sny.” “Building Classic Small Craft, pg 27)

6mm Garboard plank keel and what will be two planks.

The bevel for the scarf joint cut with the sanding disk jig. 8 to 1.

Epoxy glue

I am using epoxy glue for the scarfs.

A little weight while the epoxy cures.

I just have to insure that the epoxy does not soak into the wood and starve the joint.

probably the best scarf joint I have ever made.

In trying to make the pram light, I am using 6mm marine plywood for the first three planks, 4mm marine plywood for plank 4, 5, 6, 7, 8, & 9. Back to 6mm fo the sheer plank.

Modifying the block plane

To cut the plank bevels, I am using an idea I saw in Tom Hill’s book, “Ultralight Boatbuilding”, where you take a block plane and attach a guide to it.

Tapping the hole for the guide rod.

I drill a hole in the side of my block plane for a guide and tap it.

Such a good idea, I do it to the other side of the plane as well.
The other side as well.
Edges marked for the plank edges for the “garboard plank/ plank keel.

So the procedure is as follows: place plank onto form. Insure that plank covers appropriate ribbands. Mark plan with pencil. Edge nearer to the keel is the overlap mark. Edge closer to the sheer strake is the edge of the plank. This garboard/keel plank has two plank edge marks.

Garboard plank/plank keel cut and fitted.

Now I attach the plank to the bow and stern transoms.

Cellophane tape keeps the epoxy from sticking where it should not stick.

I use a barrier of cellophane tape to keep the plank from sticking to the forms and the ribbands.

Strapped

Lots of room for the clamps. I am using the ribbands to clamp to.

Insuring that there is not a starved joint.

I am trying not to use any nails/screws in the construction, so, one plank a day.

Time to cure

It is still quite cold, so I leave little heat on under the hull.

Plank edges beveled. You can see the pencil mark for the overlap.

The block plane with the guide works great! Mark the overlap and then plane the plank edge down using the next ribband as a guide. If I was going to use this method again, I would not notch any of the station molds. The plane hits the molds at the notches.

Plank edges beveled and cellophane tape on. Still have to tape up the ribbands.

The first three planks are 6mm.

Fitting plank #2

I lay the plank along the ribbands and insure that the plank covers them.

Marking/fitting the planks

The planks are almost 16′ long so I can stagger the scarf joints well.

Gluing plank two on.

If I have fitted the planks well, I can use bulldog clips to clamp the planks together.

Plank three.

I am putting on a plank a day. So, ten days to plank.

Plank four. Over to 4mm planking

I cut a notch in each transom for each plank. The better the fit, the tighter the seam between the planks.

Plank five.
Plank six.

I have to be careful fitting the planks. Some of the planks are not identical to their sibling on the other side.

Plank seven.
Plank eight.
Plank nine

Plank nine is the last of the 4mm planks. Plank ten, the sheer strake, will be 6mm.

Plank ten, the sheer strake. I finally get to use some of those Brenne Clamps I made.
Clamps off. All planked up.

With the hull planked, time to set the sheer line.

sheerline setting

Using the measurements from the plans and a lot of eyeballing, I mark the sheerline.

Marked and ready to cut…almost.

With the sheerline marked, the next step is to cut it out. I will have to remove the boat from the forms to cut the sheerline.

She just “popped” off of the form.

Now I disassemble the form to make space for the boat while I finish her.

Sheerline marked for cutting.

To cushion the hull, I use a big dropcloth.

Gluing on the walnut veneer

To tie the colour scheme together, I am gluing a walnut veneer to the sheer strake.

Lots of clamps and pads.

I am using Titebond II to glue the walnut veneer on with.

“Walnut” sheer strake.

I am going to use maple for the gunnels and along the bottom of the sheer strake to highlight the walnut,

Cutting the scarfs for the maple sheer strakes

My pieces of maple are not quite long enough…Time for another scarf joint.

Epoxy gluing the gunnels.

I made two sawhorses using Tom Devries’s ideas from Small Boats e-Magazine. (April 2020)

A Spanish windlass pulls the gunnels in.

Lots of clamps help, as I have to pull the gunnel strips in for a tight fit.

Maple accent strip.

To highlight the walnut sheer strake, I am epoxying a maple accent strip to the bottom the the plank. It will look good and protect the bottom edge of the strake.

Laid up

Get to use the Brenne clamps again. They actually work really well.

Time to sand

There will be a lot of sanding to do. I am aiming for a bright finish.

Gluing up the keel

I am making it out of 3/4″ maple.

Maple strips on the boil

I am going to laminate all of my knees. I rip up the rest of my maple stock and boil them up for bending.

Strips in form

I make up a form for each type of knee. Keel to Stern, Keel to Bow, two Stern to Gunnel and two Bow to Gunnel. I will make up the 12 thwart knees (Each seat will have two knees) when I do the thwarts.

Glue-up

I only have one form for each type of knee. The epoxy cures overnight.

Stern transom knee base epoxied in.
Stern, Bow and quarter knees in.
Bow knee and bow transom knees.
Stern knee and stern transom knees in. Brass mallet holds the knee in position.
Planks trimmed flush

With all of the hull knees in, I trim the planks flush with the bow transom.

Keel build

The keel is going on in two laminations. I glue on the first piece. There is enough plank left to clamp to.

Planks trimmed flush

When the epoxy has cured, I trim the planks flush. Ready for the next piece.

The rest of the keel glued on.

More sanding occurs now

Coat of epoxy

A coat of epoxy seals the marine plywood and insures that all of the plank laps are glued together.

Seat fitting

Some of the drips visible on the inside are from gaps in the planks. The tape is marking where the centre thwart will go.

Tape marks seat edges.

I am doing this to determine how much material I need to make the seats. I have not yet decided how I am going to make the seats.

Rub strips

In the meantime, I make and epoxy on the rub strips.

Hull sanded

The hull is prepped for another epoxy coat. Lotsa sanding.

Another coat.

With the outside of the hull more or less finished, I work on the seat knees.

Thwart knee forms

More ripping of maple stock.

Maple strips soaking

While the maple strips soak, I work on the seat risers…maple strips

Brenne clamps to the rescue!

I mark the hull where the seat risers should go…6″ below the gunnel.

Marking the floors.

The floors will be fitted to the first three planks, with limber holes.

Weight?

I am going to weigh the boat. I had predicted a hull weigh (planking only) of 60 lbs. What will she weigh with the knees, gunnels, seat riser and keel?

50lbs!

The hull weight is good. I am hopeful for a light boat

Bent strips and forms.

The knee strips are bent and ready to be glued up. Titebond II and lots of clamps.

Glue-up

Each strip is coated on both sides with Titebond II. The form has been waxed to prevent sticking.

Overnight dry

While I am making the seat knees, I begin work on the floors.

Scribing

The floors are scribed and then cut. I use the 12″ disk sander to fine fit them.

Still fitting

I use a pencil on a block to mark the cuts, then the disk sander to fine fit.

Cutting the limber holes

I cut limber holes for drainage.

Cutting

I use my drill press to cut the limber holes. I used a 1″ hole saw, clamped the floor in place to make the cut. I sand the limber holes smooth with a drum sander.

‘poxy time.

I have leveled the hull and level the floors as I epoxy them in.

Test fitting the walkway

After the floors have been epoxied in, I begin to fit the walkway. I am using leftover 6mm marine plywood. The gaps between the panels are for bailing access. They will be under the thwarts.

Test fitting the thwarts

With the walkways more or less fitted, time to do the seats. I got a deal on “White Maple”. I decide to use the nearly 1″ thick material for the thwarts. They will not need a centre support. I decide to add a walnut trim to the seat edges.

Walnut trim.

I have to laminate up a piece for the stern thwart.

Stern thwart

Using Titebond II for the thwarts

Thwarts laid out.

With the thwarts all glued up and sanded, I fit them into the boat.

Knees

Fitting the knees. I mark them out and use the 12″ disk sander to shape.

I will be epoxying them in using a low clamping pressure method.

Thwart knees and walkways fitted

With the thwart knees fitted and ready to go, I finish up the walkways. They need a way to keep them in place.

Maple clips

I make up some maple catches to hold one side of the walkways…Six in total.

Maple latch

I design a maple latch for the other edge of the walkway. Twist to lock, twist the other way to unlock and remove the walkways.

Making the latches

I cut a guide hole about half way into the block for the base of the latch.

First cut
Using the bandsaw

The second cut is done on the bandsaw. The latch is cut to shape.

Work in progress

The third cut makes the sloped section that goes over the walkway.

A block keeps my fingers safe.
Mock up on the bench.

The walkways have a half-circle cut into them for the latch.

Test fit in the boat.

I dry-fit the walkways in the boat. Seems OK.

To glue in the clips, I drill a screw hole, epoxy the clip to the floors and when the epoxy has cured, I remove the screw and replace it with a bamboo dowel.

Clips epoxied in.

With the walkways fitted, I am varnishing them. Time to sand the inside of the hull.

Ten coats. You can see the non-slip texture.

After the second coat of varnish, I sprinkle some ground up walnut shells for non-slip.

Two coats of epoxy and the thwarts fitted and epoxied in.

After the epoxy cures, the inside and outside of the hull gets a through sanding in preparation for varnishing.

Oarlock socket blocks fitted. Both sets of clips are in. When the epoxy cures I install the Gaco two position oarlock sockets. I only bought one pair, I order another pair from John Murray.

Flip her over and install the brass half-rounds and we are ready for Varnish, Varnish, Varnish….I drill the bow transom painter hole before varnishing so I can varnish the hole too.

Two coats a day

I put two coats a day on the outside of the hull. Rolled and tipped. One in the morning and one in the evening. Eight coats in total on the outside.

Last coat

I then flip the hull over and brush on eight coats on the inside, Thwarts and all.

Eight coats of varnish later. Bow painter hole visible.
Note the hawsehole on the quarter

Crwban will have only one line…The painter. I will use the hawseholes to run lines through.

Forward hawsehole

The hawseholes are more hand grips for carrying than hawseholes for hawsers.

After hawsehole.

I flip her right side up and paint on her name using the Papyrus font in white paint.

Crwban ready to go down to the Hollyburn Sailing Club for her launching, June 20th, 2020.

Crwban (pronounced ” Crew-ben”) is the Welsh name for a turtle. Land turtles are not found in Wales, but Leatherback Sea turtles frequent their shores. The backs of Leatherback turtles look a lot like the clinker planking on the pram.

Crwban is flying the Hollyburn Sailing Club burgee and the Vancouver Wooden Boat Society burgee. She has a Port (red) and Starboard (green) clip-on bag for stuff. Her 1/4″ bow painter runs through a painter hole in the bow transom.

Good rowing to you.

Mike