Building a new dinghy

[Ross]

I particularly like the lines of the dinghy the Roger Long published on this forum. However I have a few questions concerning the scantlings. If I were to build from the thinest plywood I could find and then tile the inside with end grain Paulownia blocks after the manner of balsa cores and glass over the entire structure I think that I could make areas that could be subject to abuse thicker and stronger than I could achive with constant thickness plywood. Is there a down side to this approach other than an increase in weight and cost? The supply of paulowina wood is not a problem. I can get a truck load.

 

[DannyS]

I hear plastic bottles filled with CO2 create good structure for boats...or maybe spent propane tanks for grills...
Oops, wrong thread.

 

[sailingdog]

I don't see why that wouldn't work, You'd probably want to taper the blocks so as not to cause a hard edge though. I'd also recommend putting a layer of kevlar cloth down under the glass on the bottom of the boat. Kevlar adds a lot of puncture and abrasion resistance, and will probably make the dinghy far more durable.

I particularly like the lines of the dinghy the Roger Long published on this forum. However I have a few questions concerning the scantlings. If I were to build from the thinest plywood I could find and then tile the inside with end grain Paulownia blocks after the manner of balsa cores and glass over the entire structure I think that I could make areas that could be subject to abuse thicker and stronger than I could achive with constant thickness plywood. Is there a down side to this approach other than an increase in weight and cost? The supply of paulowina wood is not a problem. I can get a truck load.

 

[packman]

Had you considered wet layup over foam cores? Burt Rutan builds airplane wings from it. What in the world is "paulowina wood" ? Do I sense your famous wit coming on Ross?

 

[Ross]

Had you considered wet layup over foam cores? Burt Rutan builds airplane wings from it. What in the world is "paulowina wood" ? Do I sense your famous wit coming on Ross?

I lined Bietzpadlin with Airex core from the turn of the bilge to the cabin top from the bow to the companion way bulkhead. So I am a little bit familar with composite comstruction.
Paulownia is those weed trees that have leaves as big as a steering wheel and have rather pretty purple flowers in the early spring before the leaves come out. Any vacant lot or abandoned property seems to attract their growth.

 

[sailingdog]

LOoks like this:

 

[packman]

I've done a little of that myself, mostly aerospace stuff though so I don't really know if that kind of construction is suitable for marine apps.