Romax - a two sheet rowboat

[flo-mo]

In my first thread that is about a one sheet boat design http://forum.woodenboat.com/showthre...ne-sheet-canoe I was asked for a design that maximizes two sheets of plywood.

Actually I have already developed a rowboat made of two sheets. The name of the design is "Romax" and these are the specificationes:

LOA 15,5'
Beam 45"
Centre depth 14"
Draft 5,5"
Weight 70lbs
Displacement 500lbs

Here are some pictures of a scale model I made.

[flo-mo]

I started to cut the panels for the boat and here are pictures to show you the idea of the two sheet boat concept.



two sheets of plywood



cut with a knife - no waste so far



some minor modifications



the panels are ready

[flo-mo]

Pictures of the hull

[htom]

Just a little of that "laminated wood" stuff can make things of utility and beauty. I'd like the offsets, please; this looks like a great competitor for a canoe on a car top. (Could you talk, too, about the folded people you use to populate your collection?)

[RodSBT]

Very nice, Flo Mo!

This looks like a fast boat, would be great for rec. rower.

[AnalogKid]

More about the construction techniques we're looking at would be good too.

I thought the pictures of your 1 sheet guide canoe showed a very tidy build.

Correct me if I'm wrong, but to me it looks like your process is:

1. Butt join all long panels with glass tape on both sides
   
2. Join the panels with brown parcel tape on the outside of the hull only with temporary pieces of wood for bracing
   
3. Mask lines on the inside for filleting
   
4. Run fillets of thickened epoxy on the inner panel joints

and to guess at where you are going next with this build:

1. Lay glass tape over the inside fillets
   
2. Remove the brown parcel tape and fill any gaps with epoxy
   
3. Sheath the outside of the hull with light glass cloth.
   
4. Permanently fasten inwales/gunwales and thwarts.

Do you ever have difficulties with the brown tape either not holding the edges together where the panels have a lot of curvature, or the glue coming off on the boards and marking the wood?

[JimD]

Very slick design. I built a kayak same way but used masking tape.

[flo-mo]

@AnalogKid

You are right with all points you have listed. Nevertheless I will proceed different at one point. The hull will be sheathed completely inside and outside with 6 ounce glass cloth and I think the glass tape can be omitted.




This is the tape I am using for the fourth build and I never had any problems with it. My experience is even after weeks it comes off easily without any glue left on the wood. Some fibres will stick to it but it is not too bad.



When I am pleased with the shape of the hull I use this glue with a hypodermic needle attached.



Some drips in the joint will secure that the panels will stay edge to edge in thier position.

[JimD]

... The hull will be sheat[h]ed completely inside and outside with 6 ounce glass cloth and I think the glass tape can be omitted...

Yup. Sheath first, tape later if you still think its necessary.

[AnalogKid]

@AnalogKid

You are right with all points you have listed. Nevertheless I will proceed different at one point. The hull will be sheated completly inside and outside with 6 ounce glass cloth and I think the glass tape can be omitted...

Makes sense, certainly gives a clean build with the minimal amount of fairing required. I use a lot of brown tape on parts I don't want stuck to the boat, because epoxy refuses to stick to its shiny outer surface, but I do fin a lot of residue if I leave it in place for more than a few days. I probably ought to buy better quality tape.

[Daisy Grace]

This looks lovely. You said you cut the plywood with a knife. What thickness of plywood are you using?

[flo-mo]

For this design I am using 4mm okoume plywood. In my other thread about the one sheet canoe http://forum.woodenboat.com/showthre...ne-sheet-canoe in post #41 I tried to explain how to cut the panels with a knive. This only makes sense with 3 or 4mm plywood and is not the easiest thing to do. But it sure has some advantages for this kind of design.

Using 4mm plywood for a rowboat of the size of Romax is rather extreme but the whole build is an experiment and only in the end it will turn out if it was successful.

[flo-mo]

http://s387.photobucket.com/albums/o...eet%20rowboat/

For those of you who do not mind to see a ton of pictures here is my build so far.

[flo-mo]

I think this design should also be suited for two rowers.

[flo-mo]

And here is the story about the little fellows.

First a drawing of a person just about my size (6') in the scale of the boat model (1:10) attached to a piece of 10mm kapa line (http://www.kapaplatten.de/pdf-dokume...pa_line_en.pdf).



cut along the lines



but he is still flat and stiff unlike his buddy



so he needs some joints and slowly comes to life



some more shaping and two oars and he is ready to come aboard



Cut pattern:



Red lines: Only cut at the front side

Green lines: Only cut at the back side

[htom]

The little guy is as ingenious as the boats. Thank you!

[John Meachen]

Another clean lined boat,looking forward to seeing photographs of the launching.

[flo-mo]

I am looking forward to seeing photographs of the launching too but alas due to a shoulder injury I won't be able to continue building the boat in the next 3 months.

At least this gave me the opportunity to start the threads about my designs and it is nice to see a lot of positiv reactions.

[SMARTINSEN]

I am looking forward to seeing photographs of the launching too but alas due to a shoulder injury I won't be able to continue building the boat in the next 3 months.

At least this gave me the opportunity to start the threads about my designs and it is nice to see a lot of positiv reactions.

Ouch. I hope that you can feel better soon. Please keep up the good work. You are talented and imaginative.
Perhaps you can design more boats during your convalescence.

[flo-mo]

As I can not go on with the build for a while I continue to post pictures of what I did so far.


The panels are cut already and put together like a puzzle to show the idea of the two sheet concept one more time


The same two sheets with all pieces displaced


The panels arranged in the right order with the waste material in front



Two straight cuts


and a curved cut using a card board template

[flo-mo]

These are the modifications that are necessary to make a nice stem line

[flo-mo]

I skipped the part of butt joining the panels with glass tape. The panels are ready for assembly with masking tape attached for a neat fillet later on.


This is my fancy backbone made of all kind of stuff I found in the shop


The process of tape, glue and glass begins


Assembly is tricky and needs a lot of improvisation


A wooden wedge covered with tape is screwed to the end of the sheer panel


The wedge connects the panels solidly within the correct angle. The hole made by the screws will be covered by the gunnels.

[flo-mo]

Temporary inwales with spreaders are necessary so the hull will take the desired shape.









Connection of the panels starts from the middle. For a fair hull shape a correct alignment is important.




Slowly the hull takes shape

[PeterSibley]

I am amazed !

[flo-mo]

To connect the panels I first placed the brown tape with a distance sightly larger than the width of the tape. In a second run I added another series of tape within this distance with more force and also tightened the tapes from the first run so the panels are pressed together edge to edge.


Maybe I overdid it but I wanted to be sure that while turning the hull everything stays in the correct position.


Although at this stage of the build the hull is surprisingly light weight it takes two to turn it around. Before I could do this with the help of a friend I was so curious what it would look like right side up that I took this picture and turned it around to get a first impression. It is still one of my favorite pictures of the build.


Finally it is done.

[Lewisboater]

The method is fantastic...but I really love that soft cradle..I would kill to have that much uncluttered room to build in.

[flo-mo]

The workshop belongs a very generous friend of mine. I am allowed to use the shop and his excellent tools for free and to store the boats in a seperate room. It is about time to say: "THANK YOU VERY MUCH FOR YOUR KINDNESS !!!"

There is a little drawback but how could I complain. The shop is situated in the first floor and it is not easy to get the boats in and out. I found a way to do it all by myself but it is easier with a little help. Here you see how an older build a Prospector canoe gets back in.

[sailboy3]

Lovely!

[PeterSibley]

It's a great design Flo Mo , remarkably little waste and a beautiful shape .Again ...congratulations !

[flo-mo]

Two strips of plywood bent with a heat gun will form a false inner stem.


Some drips of cyanacrylat glue and the strips are fixed.






The fillets are covered with small stripes made of document pockets that are peeled off after the epoxy has cured.

[flo-mo]

A neat fillet with a smooth surface


The fillets at the stem have also cured and the wedge that connected the sheer panels is not necessary any longer.


With a funnel the hollow space is filled with epoxy.


All fillets are finished and the masking tape is removed.

[Peter K]

I would love to try your building method on the row boat - in fact I ordered ply for my next boat yesterday, and over ordered by 2 sheets of 6 mm ply !
Maybe the next build will get under way.
Great work,
regards Peter

[aldebaran]

Really nice.
I think I prefer it to the Big Guide rowboat. More boat and less canoe. Are you going to post ofsets and panel layout on this one as well?

[aldebaran]

Bum

Just curious. Any news on the building?

[flo-mo]

Bum

I feel like a bum because I have not made any progress within the last months.

Somehow I lost my impetus and at the moment it is too cold in the workshop for epoxi work. I am going to proceed with the build as soon as temperatures will rise. Anyway I hope to launch the boat by early summer.

All I did was to remove the brown tape only to realize that there is some residue on the panels because I have been lazy and the tape was on the hull for 4 months. Before I am going to glass the hull I will have to clean it with aceton -- a necessary procedure anyhow.













Something else I did was to take the lines of the hull. The linesplan I had until now I had taken from the model I had built. The Romax design started with the shape of the panels. The panels and the sheer formed with spacers determine the hull-shape. It is a reverse design process and is based on trial and error.