I ordered the plans on Friday.

Thank you for your replies.

 Alex

No one here knew the answer. Did you ask CLC customer service?

Enjoy your build,

Laszlo

Alex, Meranti plywood has been popular for building light craft for years--longer than okoume--so you will be fine.  Thickness being equal it is heavier (badder), stiffer (better), stronger (better) ,more rot-resistant (better), and more expensive (badder) than okoume. It's a compromise.

Gory, longwinded details:

Meranti is wood from a number of species of genus Shorea, from the Phillipines.  Cheap plywood of this genus is called "doorskin" and "Laun" and other names; better quality plywood is sold by honest merchants as "Meranti", or by uninformed (or unscrupulous) merchants as "Phillipine Mahogany".

Mahogany is from one of a couple species of the genus Swietenia, which grow in Central America, the Caribbean, and at one time in Florida.  There a still some left in southern Florida.

Meranti looks slightly similar to mahogany, but not only is Shorea totally unrelated to mahogany, it is much inferior as a boatbuilding lumber.  (But if encapsulated in plastic, as in stich-and-glue technique, not so bad!).

Mahogany was wiped out as a commercial lumber by overharvesting, and is no longer available to boatbuilders.  Meranti is one of the inferior woods, along with Sapele, which took its place.  When Meranti and Sapele members of this second generation were likewise overharvested and became expensive, okoume (inferior to the second generation because it has poor rot resistance, but lighter, which is good) became the third generation.

Unsavory merchants learned from the success of the "Phillipine Mahogany" marketing ploy, and decided to name okoume "African Mahogany", or worse, "Mahogany" and soon  this became a common term for it even among honest businessmen.  Again, okoume is totally unrelated to mahogany, and its boatbuilding properties are vastly inferior to those of mahagony. But in stitch and glue, the main problem--poor rot resistance--it a fairly minor problem because the wood is encapsulated in plastc and glass.  If the integrity of the coating is compromised, then you get "black ick" but this can be fixed.

Thank you, Laszlo and Camper!

Here a sheet of Meranti BS1088 is 54$ vs. Joubert Okoume 85$.

So I think I'll go with Meranti. 10-12 lbs  more is not a big issue.

 Alex