Has anyone used thinner wood on a Batou D4?

[Paul H]

Since my D4 will mostly be used for ship to shore from my cabin cruiser, and be tied to the roof of the cabin, weight is at a premium. I picked up some 5.2mm from Lowes and was thinking about substituing it for the side panels vs 1/4". I have enough 1/4" meranti for the bottom panels, transom and bow frame.

I'm figuring I shouldn't be giving up too much strength, and slight weight savings will be a bonus. Am I missing something?

[Thorne]

5.2mm what? Does Lowes sell marine ply?

[Figment]

I think you'll save more weight by paying attention to perfectly filleted and taped seams and not oversaturating the tape.

[Paul H]

Oops, quick on the fingers. The 5.2mm ply is exterion luan, not true marine ply.

I've taped a few seams on my Tolman ;) and understand the concept of not going crazy with resin. It'll be nice working in small batches.

[Thorne]

The Oregon Messabout Yahoo group was chatting about that design, and one guy did the same thing and reports flexing/oilcanning under power in a swell.

Probably not the end of the world, and of course could be fixed by extra stringers or frames. I'd worry more about the luan rotting -- I've bought ply boats that were only good for bonfires so that colors my perspective...

;0 (

[Cuyahoga Chuck]

Oops, quick on the fingers. The 5.2mm ply is exterion luan, not true marine ply.

I've taped a few seams on my Tolman ;) and understand the concept of not going crazy with resin. It'll be nice working in small batches.

All you have to do is take a piece of luan and a similar piece of 6mm BS1088 okoume . The luan is 3 verneers, the center verneer is, usually, of unknown quality and excess thickness and may contain voids that weaken it greatly. You can break it with ease. BS1088 in 6mm is five verneers and the inner verneers must be of specified quality and thickness. There cannot be more than one ½mm (.020")void in any 8 foot run.
If you build with luan and the hull exhibits any weakness the only salvation is 'glassing the outside. There goes your target weight and whatever you saved buying the cheap stuff.
The boat in my avatar isn't made with okoume but from a high quality 3 verneer underlayment. The underlayment matched the weight of BS1088 and has prooven to have more than adequate strength. No flex, oilcanning or groaning under sail. It was a lot of work because the ply only comes in half sheets so I did a lot of scarfing. It was also covered with green x's that indicated the nailing pattern. Took a lot of time to sand all that off.
I'm cured. From now on it's BS1088.
Since I've been thru' this once I think I could come close to the 55 lb. design weight.

[Mrleft8]

Veneer. Geez Chuck.... You should know better than that!!!! ;)

[Figment]

My dinghy is luan. Money was tight and I only expected to need it for a year or two.

http://www.saltygrapes.com/photos/153281305-M.jpghttp://www.saltygrapes.com/photos/153281240-M.jpg

I think this is year five, and it's just fine.

Bronze oarlocks cost more than the materials for the rest of the boat.

[Figment]

No not kidding at all.

Well, TWO sets of oarlocks for the two rowing stations cost more than the materials for the rest of the boat.

[Cuyahoga Chuck]

Fig,
For you and Uggah, traversing small water, luan is sufficient. But, Paul H. is going to build the sailboat version of the D4 so his kids can learn to sail. His kids deserve BS1088 okoume.
I've sailed my D4 as far as 2 miles off shore. With wind power it is easy to do. Being that far from land in a boat that tips the scales at about 80 lb. fully rigged made me ponder, for a moment, whether I had any reason to worry. I didn't have to worry about the boat. It was as solid as a rock because I had built it out of the proper material.

[Figment]

Uggah? :D

[Cuyahoga Chuck]

Down in Georgia everyone knows who Uggah is. He lives in Historic Savannah and is the mascot of the University of Georgia Bulldogs. I haven't been there for decades but, they were up to Uggah IV or V when I last heard. Also I may have gotten his name wrong.
Sorry, it's "Uga" and they are up to Uga VI right now.

[Figment]

ah, up here in Ivy Leage country, it's "Handsome Dan". Last I checked, they were on number 16 or 17.

[Paul H]

Thanks for the comments and concerns. The kids won't be using it for sailing in heavy winds several miles off shore, they'll be dinking around on a small lake. The boat primarily will be used for rowing to shore in protected anchorages. Weight is critical in getting it on and off the pilothouse.

If the kids show an interest in sailing I'll build something larger and more capable in the future.

I'll let all know if the luan proved to be an unsuitable building material. I will double up the gunnels to provide some more stiffness on the top of the sides.

[Jeff Robinson]

I built it of the recommended materials and it is much more weight than is convenient. I heave it off and on a dinghy rack at the club. The weight means it gets banged around on the way down. Did it again I would go the lightest way.

JR