Iroko on deck

[Mike Ludgrove]

Has anyone out there had experience with iroko laid on deck. If quarter sawn 3/4" am I likely to get reasonable durability when epoxied over glassed marine plywood?

[John Meachen]

Why do it?A glass sheathed ply deck is about as good a structure as you could hope for and you are just adding weight.

[Simon R]

There's a leaflet from Robbins that suggests that the Teak, Iroko or whatever should not be thicker that about 3mm or you will just get too much movement:

www.robbins.co.uk teak_decking_guide_epoxy (http://www.robbins.co.uk/Pdf%20Files/teak_decking_guide_epoxy.pdf)

To go thicker you might need to bed the timber into some kind of rubber - capable of absorbing the greater movement:

www.robbins.co.uk teak_decking_guide_caulk (http://www.robbins.co.uk/Pdf%20Files/teak_decking_guide_caulk.pdf) and www.saba.nl (http://www.saba.nl/index.php?id=438&L=4)

I've limited experience, but all I've read and heard suggests that, however it is done, laying timber over ply will fail. The decks I am ripping up now, laid less than 20 years ago, were 3/4" ply with 1/4" Teak on top, bedded into some kind of rubbery stuff. The rubber had gone hard, split away and water had leaked through. Rot reduced the ply to something about as strong as breakfast cereal.

[Simon R]

Just thought I'd add some pictures. Teak on top looked OK, but the ply underneath is shot:

http://www.ceze.net/aaa/rot1.jpg

http://www.ceze.net/aaa/rot2.jpg

Simon

[Andrew Craig-Bennett]

Has anyone out there had experience with iroko laid on deck. If quarter sawn 3/4" am I likely to get reasonable durability when epoxied over glassed marine plywood?


1. Don't do it - for the reasons given above!

2. I recall a boat that was built with laid quarter sawn iroko decks - she was built by a very good builder - Arthur Holt of Heybridge in Essex, England - for a very experienced owner. There was an unexpected problem. The iroko was durable enough but unlike teak it develops a huge number of tiny surface checks and the result was that dirt lodged in them and she had permanently black decks - not pretty. They got painted!

[Mike Ludgrove]

Thanks for replying guys;seems I'm going to have to rethink this one. There are a number of suggestions in the forum relating to using Ipe as a teak deck substitute,the economics and availability of which I have yet to discover.

[Simon R]

... the result was that dirt lodged in them and she had permanently black decks ...

That's bad news, I've been planning solid Iroko decks. I saw some weathered Oak recently, it was dark dark grey and very beautiful. When you say Iroko goes black do you mean it looks dirty, or just dark? I don't have a problem with dark.

I've been looking at many deck options. Good quality marine ply is expensive, per cubic foot, and will fail if overlaid with timber. Solid timber is more durable but needs to be thick. The problem in a boat's deck is not absolute strength, it's relative movement. The advice I've had is that the timber needs to be an inch and a half thick and laid on adequately thick beams at least every 18". Any less and the planks will move relative to one another and the seams will open.

It's a problem on a small boat because an inch and a half thick deck is heavy. So I can see why thin decks have been built and then got a reputation for leaking. The boat I'm working on is about 45 tons, so thick decks are an option.

I'll have a look at Ipe, it's not one I'd heard of.

Simon

[Andrew Craig-Bennett]

Simon - the "experienced owner" was Michael Emmett, the boat before this one:

http://www.traditionalcharter.co.uk/default.htm

It looked dirty.

I agree that one and half inches is a minimum thickness and in teak this is going to be eye wateringly expensive!

However, people used pine before they tried teak and a pine deck can look lovely, if maintained. Certainly better than oak which is
completely unsuitable as it moves and checks if left uncoated.

Coelan over a pine deck is another possibility but the appearance whilst striking is non-traditional.

When my teak decks got down to an inch and a bit I painted them with Coelan and put deck paint over the top; this was done as a temporary measure but with the passage of 14 years I now consider it permanent.

[PeterSibley]

Has anyone out there had experience with iroko laid on deck. If quarter sawn 3/4" am I likely to get reasonable durability when epoxied over glassed marine plywood?

I'm not expressing an opinion on this matter as I really have none , but below are a couple of photos of the deck of George Maynard's Zulu .3/4" Iroko over ply ,if I remember correctly .He seemed very pleased with the result .

http://pic40.picturetrail.com/VOL282/9443996/17245530/363329058.jpg

http://pic40.picturetrail.com/VOL282/9443996/17245530/363329054.jpg

[Raka025]

Has anyone out there had experience with iroko laid on deck. If quarter sawn 3/4" am I likely to get reasonable durability when epoxied over glassed marine plywood?

The most recent Woodboat Mag had a similar deck foundation except with Douglas Fir.

[Boatsmith]

Boats that are imported here from Europe usually have teak decks that are 1/4" (mm0 or less in thickness. In my experience this is to thin. Normal wooden deck maintenence is sanding. All wooden decks absorb dirt and the soft grain weathers away and you sand them to clean and level them. A 1/2
"thick teak deck that we put down on a new high speed lightweight sportfisher lasted 10 yrs. The boat was in daily charter use in South FL and the decks were sanded 3 times a year. They were installed with epoxy over plywood (cold molded hull) and were calked with Maritime Wood Products Teak deck calk. The calk seams were not rabbits but were the full depth of the plank. There were no fasteners used either temporarily or permanently. When we installed a new deck the only removal required was to sand the remaing teak flat to remove the remaining caulk. We use starboard spacers to space the planks and 25 lb (11kg) bags of lead shot to clamp the teak down. Our decks are fabricated by assembling panels in our shop to fit the particular boat. WE vary the plank widths minutely so that the edges of deck hatches and the piano hinges fall in line with a caulk seam. This takes some extra time but the result is very nice. We then align the panels on the boat and use small blocks of wood with mylar tape on the edge glued to the plywood(or frp) to fix the location. Then we pull up the panel and apply epoxy and then place the lead bags to hold the teak down for curing. We limit our individual panel widthto prevent air entrapement andbecause any larger would be dificult to handle. Most of tekdecks are installed on high end sportfishers and motor yachts. When we do sailboats they are sometimes assembled one plank at a time or sometimes off site. Sailboats usually have sprung decks so when we build panels off site we must glue them to a plywood or frp substrate to hold the curve until installation. This requires them to be built upside down. We do many large teak decks in remote locations by flying out and building doorskin patterns and then building the decks in our shop and the shipping the parts back and then installing them.We also have repaired many teak decks by refastening, resawing the caulk seams,re caulking and sanding. Also we never use tape on the bottom of the seams. Modern deck caulk retains its elasticity for a VERY long time. David www.boatsmithfl.com

[ChrisF]

I have both teak and iroko exposed to the weather on my own boat. Based on this experience of thirty-odd years I would say that the notion of using iroko to substitute for teak is a complete snare and delusion. The iroko checks like mad, and is generally coarse and unpleasant.

[Simon R]

I agree that one and half inches is a minimum thickness and in teak this is going to be eye wateringly expensive!

However, people used pine before they tried teak and a pine deck can look lovely ...

I've located lots of high quality Douglas Fir 12" x 3", in 18' lengths. Straight grained and knot free. It can be ripped down sideways so that every plank is effectively quarter sawn.

In the quantity I need they can do a very good price. Looks like that's the answer.

Simon

[peter radclyffe]

That's bad news, I've been planning solid Iroko decks. I saw some weathered Oak recently, it was dark dark grey and very beautiful. When you say Iroko goes black do you mean it looks dirty, or just dark? I don't have a problem with dark.

I've been looking at many deck options. Good quality marine ply is expensive, per cubic foot, and will fail if overlaid with timber. Solid timber is more durable but needs to be thick. The problem in a boat's deck is not absolute strength, it's relative movement. The advice I've had is that the timber needs to be an inch and a half thick and laid on adequately thick beams at least every 18". Any less and the planks will move relative to one another and the seams will open.

It's a problem on a small boat because an inch and a half thick deck is heavy. So I can see why thin decks have been built and then got a reputation for leaking. The boat I'm working on is about 45 tons, so thick decks are an option.

I'll have a look at Ipe, it's not one I'd heard of.

Simon
for what its worth soren larsens deck is iroko, 1948, dark but good, but coarse for a yacht

[peter radclyffe]

I'm not expressing an opinion on this matter as I really have none , but below are a couple of photos of the deck of George Maynard's Zulu .3/4" Iroko over ply ,if I remember correctly .He seemed very pleased with the result .

http://pic40.picturetrail.com/VOL282/9443996/17245530/363329058.jpg

http://pic40.picturetrail.com/VOL282/9443996/17245530/363329054.jpg
Peter, can you tell us how merbau compares to teak, it looks similar but we dont have it in n.europe

[Andrew Craig-Bennett]

Yes, I think so. I would apply Coelan over it - its compatible with Sikaflex if you use that in the seams, and will keep the decks looking nice in our climate if you don't have a paid hand to scrub then daily.

[peter radclyffe]

Simon - the "experienced owner" was Michael Emmett, the boat before this one:

http://www.traditionalcharter.co.uk/default.htm

It looked dirty.

I agree that one and half inches is a minimum thickness and in teak this is going to be eye wateringly expensive!

However, people used pine before they tried teak and a pine deck can look lovely, if maintained. Certainly better than oak which is
completely unsuitable as it moves and checks if left uncoated.

Coelan over a pine deck is another possibility but the appearance whilst striking is non-traditional.

When my teak decks got down to an inch and a bit I painted them with Coelan and put deck paint over the top; this was done as a temporary measure but with the passage of 14 years I now consider it permanent.
ostrea rose, i guess, i agree pine is good & can be fed with deks olje

[Andrew Craig-Bennett]

Yes - do you remember Arthur building her? I do.

[peter radclyffe]

Yes - do you remember Arthur building her? I do.
i dont, i bought a boom from holts about '75, for a land yacht i built on mendlesham airfield, about 20 years ago emmett asked if i'd lengthen his smack, i agreed, thats the last i heard of it, what is your avatar Andrew

[PeterSibley]

Peter, can you tell us how merbau compares to teak, it looks similar but we dont have it in n.europe

I'm sorry Peter , I can't help you .I really have very little knowledge of tropical hardwoods .I avoid buying them on enviornmental grounds .

I have a fairly good knowledge of Australian hardwoods ....should that be of any help !:)

Peter

[Andrew Craig-Bennett]

i dont, i bought a boom from holts about '75, for a land yacht i built on mendlesham airfield, about 20 years ago emmett asked if i'd lengthen his smack, i agreed, thats the last i heard of it, what is your avatar Andrew

37ft gaff cutter "Mirelle", designed by WM Blake jointly with her first owner Philip Allen, built of teak on oak by Claude Whisstock at Woodbridge in 1937.

The avatar picture was actually taken by Robert Simper during an Old Gaffer's Race in the early 90's.

http://i535.photobucket.com/albums/ee352/acraigbennett/Mirelleracing-2.jpg?t=1241603047

http://i535.photobucket.com/albums/ee352/acraigbennett/Mirelleonhermooring2003.jpg?t=1241603127

[peter radclyffe]

I'm sorry Peter , I can't help you .I really have very little knowledge of tropical hardwoods .I avoid buying them on enviornmental grounds .

I have a fairly good knowledge of Australian hardwoods ....should that be of any help !:)

Peter
yes, thanks it would be, ive used a bit of jarrah, & greenheart which come over here for sea defence, i grew up on an 1878 payne yacht, which had a kauri deck, but i dont know much, but you seem to have terrific woods

[peter radclyffe]

37ft gaff cutter "Mirelle", designed by WM Blake jointly with her first owner Philip Allen, built of teak on oak by Claude Whisstock at Woodbridge in 1937.

The avatar picture was actually taken by Robert Simper during an Old Gaffer's Race in the early 90's.

http://i535.photobucket.com/albums/ee352/acraigbennett/Mirelleracing-2.jpg?t=1241603047

http://i535.photobucket.com/albums/ee352/acraigbennett/Mirelleonhermooring2003.jpg?t=1241603127
lovely, i guess a bit like jorrocks 2, or fifes dirk 2 , but its a long time since ive seen her,

[Andrew Craig-Bennett]

Funny you should mention Jorrocks II, I know her present owner (in Faversham) and have sailed on her - she and Mirelle spent a couple of winters in adjacent mud berths in Faversham and the comparison was interesting - both are pretty much the same size and indeed very similar but, as my sister put it at the time, "Mirelle is definitely more "butch"!" - she has another ton and a half of displacement, less sheer, more freeboard and a decidedly harder bilge. She is noticeably drier. In terms of speed I suspect Jorrocks II has the edge to windward and in lighter weather and we would get away from her reaching and in a blow.