School Holidays Project

Hi all
Looking to do a marine water craft project with my daughter who is currently on two weeks school holidays

Be good to have something we can on various days play with:
Row
Pedal
Sail
Electric

Doesn't have to be amazing at all the stuff. Just something we can row one day, sail the next, try to fit pedals the day after and such

Also, the sail thing would have to have some very simple rigging and usability as well as able to make at home from common materials like hardware shop tarp if that works. We have never tried sailing, and we have some friends that can show us what to do


Something that we can quickly and cheaply finish off in a couple of days or so. I have been thinking of a SUP like board but not that massive. Maybe setup like a tri with barely skimming floats

I am able to easily make things like paddle wheels and pulley/belt drives. I would like us to experiment with electrics. I have a 60lb thrust Watersnake with foot controls and 130 amph dry cell battery (all new) and would like to try some motors as inboards too. Forward facing rowing is appealing. A sailboard sail thing seems easy. I love the look of the crab claw sail too, and we could pretend to be Fijian cannibals on a raid

So, looking for ideas on what kind of boat style. What comes to my mind is a sit on top type board under 10' made with layers of XPS sheets. I have this available l0cally
Bastion 1200 x 600 x 50mm XPS Multi-Use Insulation Foam Board - Bunnings Australia https://www.bunnings.com.au/bastion-1200-x-600-x-50mm-xps-multi-use-insulation-foam-board_p0139536
2440 x 1200mm x 4mm F22 Hardwood Plybrace - Bunnings Australia https://www.bunnings.com.au/2440-x-1200mm-x-4mm-f22-hardwood-plybrace_p0151671

I have some 400 or so double bias and epoxy left. Some 6 and 9mm marine ply off cuts for things like stringers and bulkheads. I am able to hand apply marine *****l or spray with auto acrylic

 

Not sure about pedal drives, but a PDR is among the easiest you can build for row/sail--it's designed that way. Also easy to adapt for a small outboard motor; just beef up the transom a bit.

Puddle Duck Racer - Easiest Sailboat to Build and Race https://pdracer.com/

 

One week ago you said :
"I have some experience in the actual fabrication part of a pipe like that. It's not that different from building an MDF transmission line. The only real difference is the glass skins and PVC foam instead of MDF. Previous transmission lines were done before I started using composites. Using kerfing to slit up the MDF and wrapping it on a stormwater pipe section is how I did them. School holidays are coming up next week. I think it's an excellent experiment with my kid. A pedal powered beach toy would be cool, and we will try some homemade impellers inside the tubes. We will use XPS as the build material and method will be strip planking on cardboard tube formers that can be wetted and removed after gluing. Flat glass/XPS deck over the tubes and bask in my speedos with feet on a pair of pedals We will make bundles of strips to see how many we need to float us clear out of the water before forming them into tubes"

So I thought you were going to build a tube for a hull form to test your least wake idea?

 

Thats a good one. Looking more into that right now

I estimate a short of 9 sheets for that project. There is only one outlet here that sells XPS and they are struggling for stock in a lot of departments. Are you really keen on this experiment? Maybe we can do something

Today we will make a grass sled. We have some good grass slopes. Will make it like a very shallow PD racer. I have some spare HDPE trailer bunk liners. I wonder if two or three strips fitted like strakes will give good tracking in the cut grass. weight is in the back where the bum rests on a short sled so straight line stability is an issue. Doesn't anyone here try to use things learnt in boatcraft to make some kids projects?

 

I am not too keen on that experiment, perhaps it is best done with a model boat first rather than invest in all that material for something that might yield dismal results. Model boats have been a long standing kids project in boat cultures around the world.

 

Xps is terrible for glasswork. It WILL delam.

I used it for canoe amas following Dierking. It is a bad idea to use it. A well built sup can last a lifetime.

The amas I made are 4' long and about 8"? Wide by 6" high midships. They are small and a delam bump doesn't matter.

the xps sup will delam from standing on it

don't believe me? Walk on a piece of 1.5" thick xps back and forth, then jump. The glass you add does not change that unless you build a mostly solid frp sup and then it is going to cost a lot in resin and be heavy as ...

 

I can't get my head around scaling as I don't know enough about that. Also don't know how to implement a human power at scale size. Visited the reuse/recycle site hoping to find some polystyrene but no joy. Still curious about it though as there might be some green points as we are in a marine park area with turtles and dugongs and such

Not the right material to just glass for floors. You need to stage your skins. For flat faces, use thin ply. For curved areas use 1-2mm nylon polyester fabric (very stretchy type) then glass cloth then dynel over the glass

A hammer will bounce off the curved surface, shows it can take an impact. I am close to 100kg, standing on curved surface doesn't damage it. The tender that I made didn't require walking on the curved surface and doesn't see anything harder than water when rowing. It is still used for commercial fishing (cast netting) and has gone through 9 hurricane seasons in the tropics

Did you only use glass cloth?

 

We did some projects. Made a custom sized bed. Made a ply grass sled. It didn't work as expected. Tried a HDPE knee board and that didn't work either. Neither did cardboard sleds. Maybe the slope isn't enough. Next, we'll fit some wheels to the sled

New project, an on water fitness machine. We scored a couple of large sailboards for $10 each at the reuse centre. I need to learn how to make a rowing system that furls and unfurls the whole body and turn one of them into a rowing tri if that hull is suitable for rowing

 

Again, if you only use the xps for a mould, it is fine, but xps is useless as a hull material as it lacks both shear and compressability.