Aquatek vs Okume

[Three P's]

I am building the Pooduck (ply lap) and am finding myself in a predicament. A local lumber supplier has Okume Marine ply and Aquatek plywood on hand. They do not have Hydratek, which I understand is better than Aquatek. I also know that of the three types of ply mentioned here, Okume is the way to go.

Now; Okume is more than twice the cost of the Aquatek...If I am planning on painting all of the plywood on this boat does it make a bit of difference in the grand scheme of things if I were to use the Aquatek?

I have searched and from what I understand Aquatek doesn't use the same epoxy as Okume Marine and/or Hydratek. Yet Okume is very soft unless you glass it (defeats the "woodenboat" idea if you ask me). Again, this is just what I am understanding.

I can get Hydratek but not here. I need to have it shipped and after shipping and all of the other associated fees I may as well go with Okume. Any suggestions? The boat will not be stored in the water and will be for light use on lakes, with very few exceptions. I also understand that the Hydra/Aquatek wood is heavier. Thanks!

[Thorne]

One of the posters on this forum wishes he'd spent the extra $1000 on the lighter Occume -
http://forums.bateau2.com/viewtopic.php?f=2&t=2956

As usual it is a compromise - weight vs cost vs longevity/quality. Is the Pooduck build impacted by weight issues? Do you want it to last for years, aka "heirloom build"?

In most cases a good coating of primer and paint should give a drysailed marine ply boat all the protection it needs, assuming you store it properly out of the weather.

[PaulC]

Hydratek is significantly heavier. It's getting tough to wrestle a 1/4" sheet of the stuff anymore. It is nice plywood though.

[Steve Lansdowne]

Hydratek and aquatek are meranti plywoods whose surface plies splinter easily when being cut, I found, and thus some of my plank edges aren't crisp. Nonetheless, their price is less. I'd consider getting hydratek or occume for planking, leaving aquatek for decking where the quality is perhaps less important for a dry sailed boat that lives under cover when it is not in the water. These meranti plywoods are heavier than occume, but I believe they are less subject to rot over the long term.

[pipefitter]

The one with the most plies, which less of is usually a symptom associated with cheaper panels, wins. The only time I would opt for less plies is in the event that the surface veneers are equal thickness to their inner plies. Also, if by chance that the face veneers happened to be substantially thicker in one brand panel over another. The practice of using minimal face veneers are doing strange things to plywood these days.

I am not familiar with the pooduck skiff but is there a ballast requirement? If so, the weight differences between different panels on a small boat can become moot in short order. I have seen some boats built that are too light and needed to have weight added after the fact. In some instances, there has been a trend to follow cartoppers and other ultralight builds and does not always fit across the widely varied design criteria. In some older wood boats I had, it was the extra heft that made for a better ride, less prone to straying from wind effect etc, even when resting at anchor.

[Daniel Noyes]

Can you get marine fir in Utah?
It would be a shame to have to settle for a exotic wood species.
We have multiple sources for wonderfull Fir ply here in Newengland but we have a robust wooden boat building industry and pretty easy access to the very best of materials

[Three P's]

thanks to all. yes, I can get Marine Fir. I believe it is B/C grade? I didn't look into it much. Any ideas/gripes/likes on that? Weight is not a huge issue with the pooduck, I don't think. It does not have a ballast.

[pipefitter]

I dislike modern fir that I have seen and used. It has football patches in the face veneers and comes with grain checking brand new. It's heavier than the other mentioned panels. The last good fir marine plywood I got was maybe 9 years ago, was 3/4 and it had 13 plies. Lately, the best I have seen in 3/4 has 9 and shares that same, paper thin face veneer as it's tropical species competitors. The meranti I built my boat with was 9mm(close to 3/8") and had 7 plies, the panels very flat and consistent. Fir marine ply was never really considered a true boat building panel around these parts and was always sold as "Marine Exterior", which meant that it was suitable for homes and buildings on the waterfront. Boat builders that used it here, typically covered the exterior with polyester resin and chopped strand mat. It took resin pretty well for working boats that were expected to last maybe 10 years.

If I was going to consider fir, it would be a quality MDO.

[Cuyahoga Chuck]

Okoume is a tropical hardwood. Since it grows all year long it doesn't have the early wood/late wood common to temperate zone softwoods. Quality okoume has surfaces as flat as a pool table and if handled carefully little or no fairing is required.
Fir not only will check it will be near impossible to conceal the wild grain patterns without a lot of filling. In he end okoume makes finishing a snap and finished bright it can look like furniture.
When you are offered ply that is BS1088 that implies the product complies with the British Standard1088 which contains a laundry list of requirements. If you know the what the standard contains and you get a panel that doesn't comply you have a legitimate beef with the seller.

[bigrob]

For what it's worth, I used sapele for all the plywood for my Pooduck, and paid roughly $1150 including $150 shipping back in March. This was 1.5 sheets (4' x8') of 18mm and 4 sheets (4' x8') of 9mm. I considered using okoume for the 9mm, which would have saved me about $250 - $300 on the (4) 9mm sheets. The supplier didn't recommend the 18mm okoume because of quality issues at that thickness.

In the end I decided to go with sapele and not coat with epoxy. With okoume most folks recommend epoxy coating the entire hull. The extra epoxy used would have made the price difference between sapele & okoume less. Epoxy coating of marine plywood is a religious argument I don't have enough experience to comment on. I have coated the outside of the bottom plank and the garboards with 6 oz. fiberglass cloth/epoxy, but intend to use good oil base paint on the rest of the hull.

Bob

[One Mule Team]

Regarding the discussion of fir plywood as a boatbuilding wood, there are plenty of dry sailed driftboats out here I've seen that are fifty+ years old. Believe me, floating whitewater rivers of western Oregon subjects a boat to plenty of abuse so it certainly can last. Barrier coating with epoxy should prevent checking as would glass cloth. Of course, those 50 year old boats were built with 50 year old ply when we still had plenty of old growth fir.

My driftboat is built of fir ply and I didn't barrier coat it with epoxy and it definitely is checking in parts which is a bummer but it is 7 years old and absolutely shows no signs of dying within three years (and I guide out of it.)

[Cuyahoga Chuck]

Regarding the discussion of fir plywood as a boatbuilding wood, there are plenty of dry sailed driftboats out here I've seen that are fifty+ years old. Believe me, floating whitewater rivers of western Oregon subjects a boat to plenty of abuse so it certainly can last. Barrier coating with epoxy should prevent checking as would glass cloth. Of course, those 50 year old boats were built with 50 year old ply when we still had plenty of old growth fir.

My driftboat is built of fir ply and I didn't barrier coat it with epoxy and it definitely is checking in parts which is a bummer but it is 7 years old and absolutely shows no signs of dying within three years (and I guide out of it.)

There is no ply made in America today that is guaranteed to be as good as what you could get at any lumberyard 50 years ago. The ply mills can sell everything they make so craftsmanship is not part of the manufacturing process any more.
If a ply boat was built with panels that had hidden voids there is always the chance that moisture will get in there and cause rot. Since the rot starts on the inside it won't be seen till it is well along. Also voids, if large enough, can be a structural defect that won't reveal itself until the boat is in a difficult situation.
In the BS1088 standard the total allowable voids in any 8 foot span is ½mm. That's .020"!
With any 3 veneer plywood it's possible to backlight the panel with a spotlight and see interior voids that are at least 3/8" across.

[One Mule Team]

That is true. The fir plywood from fifty years ago was far superior. I've seen some really bad fir ply marketed as marine with huge voids. very disapointing. I needed to replace my driftboat flyline deck in a hurry and ended up having to go with ABX because it was very obviously better than the marine I was looking at.

But there is still some good marine fir ply around-it is hard to find. If I were looking for some I'd be tempted vbut would probably decide against trying a canadian supplier as they still log their remaining old growth at a voracious pace. I know of many, many examples of fir boats from fifty to five years old around here that are fairly nice.

[One Mule Team]

Please forgive my somewhat slavish and perhaps unreasonable devotion to douglas fir. I'm an Oregonian . . . I can't help myself!

[pipefitter]

Ironically, the checking that modern D-fir ply comes with, makes a good, intermittent key for resin. I used it for the upholstery forms in my boat and coated it with resin/glass. I used it for the sheer decks and the raised decks as well but fairing was a nightmare. The grain printed through the glass cloth. I did not save a nickel by using it, including considering the freight charges for the meranti.

I have shown these pictures before. Being that this thread contains questions on both, I will show them again and you be the judge.

Take into consideration that the meranti has 'at least' two years more to the weather, was covered in composted oak leaves. Both are considered moderately durable. Also, note the difference in the epoxy coated section of the meranti.

Meranti, left. Fir on the right. Both are 3/8ths.

http://i99.photobucket.com/albums/l309/tigmaster/P5050027.jpg

Meranti drops sitting above ground to the weather such as the fir was in the above picture. The fir above had been outside for a year, the meranti, 3+ years.
http://i99.photobucket.com/albums/l309/tigmaster/P5050023.jpg

D-fir showing both a topside to the weather and a piece on the left that was against the earth. Notice the extreme checking. Painted or not, these checks hold moisture longer and mold will make a condo of these checks which highlights the condition even further, especially against white paint.
http://i99.photobucket.com/albums/l309/tigmaster/P5050028.jpg

Guess which I will choose for any boats from here on out?