5'x10'x5' Grumman 3 idea

[jimqpublic]

Shamelessly stolen from Andrew's design for the Grumman 2, I stretched it vertically to 5'. Inspiration for raised bed with storage under was from the "Chief" in the teardrops book.

Doing the math I have learned that 5x10x5 teardrop is roughly 200% as much interior volume and 160% as much wall, bulkhead, ceiling, etc surface as a 4x8x4. The reasons for 5x is if using birch plywood in 5x5 sheets the waste is minimal- similar to 4x when using 4x8 sheets. I really like the under-bed storage and partly inset wheel wells.

I stretched the profile up by 1'. Wheel/axle/fender was not stretched in the main profile view- but was over in the section view. I moved the bed to just over the wheel well box giving 3'3" of headroom and about 12" of storage depth under. Since I stretched it vertically some items are a bit out of proportion. The other changes were a first pass at shifting around the galley and cabin cabinets.

With the vertical stretch, the counter top can move back a little because the rearmost "bulge" in the back profile moves up. I'd like to play around to see if a pleasing rear profile can be designed where the counter top is right at the longest point.

All I have right now is a .pdf. If someone can turn it into an image that would be great.

Andrew's 5x10x4' Grumman 2 web page

My 5x10x5' Grumman 3 .pdf file in Google Doc's

[Ageless]

[aggie79]

I like the "stretch." It retains the clean lines of the classic proportions.

I like (and used) baltic and russian birch, but you may want to check around for some 5' x 10' sheets to keep from having to splice them. Our local specialty sheet goods supplier has 5' x 10' (nominal) douglas fir plywood in 1/2" and 3/4" (nominal) thicknesses.

There is a little per square foot premium in the price compared to 4' x 8' plywood, but it sure saves a lot of work. I used a sheet of the 3/4" for my assembly table top.

[jimqpublic]

Thanks for the mention of 5x10 plywood. I would want to make this 5x10x5 as light as reasonable. So the structural wood would also be my interior surface.

Using 5'x5' x 12mm birch for the walls I wouldn't use any additional framing except trim rings around the doors, and it's thick enough to dado a groove for the headliner and bulkheads. One consideration to insulate the walls is to use 1/4" high density foamcore under an aluminum or Filon skin- but with no additional framing. That puts the middle of the wall plywood 1/2" from the outer edge- good for screwing on 1-1/8" RV insert moulding.

I think the doors could work well with the rear edge at exactly 5', so there really wouldn't be much of a seam anyhow.

If I were going with wall framing, 1/4" plywood inner skin and aluminum or Filon outer skin would work. 5'x10' Okoume BS1088 rated marine ply in 6 mm thickness is available locally for about $120/sheet- Expensive but only one sheet for each wall. It's also light at 30 pounds for a 5x10 sheet. That's probably way too thick for the roof curves though so I would need to use either 5x5 3mm birch or waste a lot of expensive Okoume from 4x8 sheets. (I do have 5 sheets of 4 mm Bruynzeel Okoume in the garage that have been gathering dust for 15 years)

Not sure if I like the looks of Okoume as much as birch though.

5x9 5/8" fir "ping pong table" plywood would work great for the floor- heavy but easy and cheap compared to birch or okoume.