Washboards

[coopec]

Just for completeness, it's also worth asking what 'sort' of washboards do you want?

If it's something to keep the wind and rain out and even let the light in, then 9mm ply or any of the 'plastics' are fine.

But if the boat is a 'offshore' cruiser and you are contemplating being out in bad weather, then washboards are an important component in the boat's watertight integrity. They must be capable of not only withstanding a considerable blow if pooped by a wave (especially if a crew member gets 'washed' against them), but must stay in place should the boat be knocked down, even if the companion way hatch is slightly open.

in extremis.

Your post echoes my sentiments entirely. When I have read someone suggesting acrylic sheet for a washboard I hope they are doing nothing more than coastal cruising.

You are obviously expert in this area so I would appreciate your thoughts on mine. The acrylic sheet is 8 mm and I will be through bolting it with 8 small s/s bolts. The ply is 3/4 inch. The gap between the hatch and the washboard is minimal. I thought there might be a possibility the inside holding timbers could split, even though the type of timber I have used is very strong. To counter that possibility I will use square "washers" on the inside of the timbers as reinforcement.

View attachment 41149

 

[William_H]

Why wood on a GRP boat. Consider making GRP wash board. It can be quite simple and an interesting exercise. Start witha flat surface ie glass or wood larger than the size of the wash board. Give it a liberal coat of wax and or cling film or polythene cover. Use polyester resin using a gel coat with pigment for the colour you want. Lay down a thick coat of gel coat. Wait until it is gelled ie not hard but then not runny. Lay over that woven glass then chopped strand mat to get half the desired thickness of the edges. ie the edges that go in the slots each side. Get some polyurethan or polyester foam I would imagine about 1cm thick cut to a size about 2cms smaller all round than the wash board. Chamfer the edges to about 1cm in on one side so that when the foam is layed on the GRP there is a gentle transistion from the already laid GRP for further glass to be laid over the foam. Add more layers of glass over the foam and out to the edges of the washboard until the final thickness at the edges is acheived. Again when the resin is setting and nearly hard apply a coat of gel coat with pigment for the inside.
What you get is a washboard that is thick enough to make it very rigid because of the foam. The foam will provide insulation and floatation.
Other options might be to use carbon fibre for the layup giving added strength and stiffness. Not as expensive as you might think.
I think the primary consideration is resistance to kicking for security as said. Give it a go olewill

 

[Daydream believer]

On my brother's boat he had some washboards made up from some mahogany - they looked lovely. However in warmer weather - we do get some occasionally - they do tend to warp quite badly. They straighten up again when cooled. I've not seen that with ply.

use clamped ends & the horizontal joints should be tongued & grooved with no glue & a slight tolerance to allow expansion & contraction

 

[Robert Wilson]

On my brother's boat he had some washboards made up from some mahogany - they looked lovely. However in warmer weather - we do get some occasionally - they do tend to warp quite badly. They straighten up again when cooled. I've not seen that with ply.

Because jointing it together into something large enough for a washboard will be a bugger, especially if you don't have a router or a biscuit jointer. Then it will probably warp.

Pete

Big advantage of off-cut flooring is that it's already T 'n' G'd, and put together in vertical panels it doesn't warp (if braced with overlapping "drip strips" of the same material)

Note to self - must shave off a little bit as if left in over winter they expand just a fraction and become tight to lift out.

 

[reeac]

Why wood on a GRP boat. Consider making GRP wash board. olewill

Depends on your personal taste. I think that some varnished timber "highlights" greatly improve the appearance of a GRP boat. I have varnished timber washboards and tiller - both easily removeable to take home for refinishing under workshopconditions - and a painted Winter Washboard which takes over during that season. The lowest marine ply washboard has a lip of solid teak along its lower edge to combat any standing water.

 

[Ruffles]

I'm sure people like Howells will supply the quantity you need. I see they sell 1/4 sheets.

You will still need some solid teak to make the edges. Suggest half inch - or copy the originals!. You shouldn't need any special tools except, perhaps, for a plug cutter/screw setter set to attach the edges. Suggest No8.

I made replacements from solid teak. Easier as you're only edging the end grain at the sides. Looks lovely but a lot heavier than the original veneered ply which is a bit of a pain. In retrospect should have gone with ply.

One complication: If you want bring the originals home to copy you'll need to make some temporary boards so you can lock the boat!

 

[Ruffles]

Depends on your personal taste. I think that some varnished timber "highlights" greatly improve the appearance of a GRP boat. I have varnished timber washboards and tiller - both easily removeable to take home for refinishing under workshopconditions - and a painted Winter Washboard which takes over during that season. The lowest marine ply washboard has a lip of solid teak along its lower edge to combat any standing water.

I have the same 'rule'. The only varnished stuff are bits that are easily removeable so can be done on the kitchen table.

 

[Hadenough]

The time has come to replace them. However, since I'll have to buy a whole sheet of 9mm marine ply at €105, I was thinking of staining some exterior grade WBP birch ply at a third of the price, since it won't actually be immersed in water. Views?

Over here I bought a full sheet of 9mm marine ply from Travis Perkins for £65 in January. On working it I found it was very good quality with almost no voids. Face finish was good too. I think they have a branch in Limerick, dunno about Dublin.

 

[Neil]

I have some T&G oak flooring that could be put to use. However, the back face is ridged - I'd have to plane/sand it down, failing to find someone with a thicknesser. The edges would have to be routed back to 8 mm, I could do that. Why run the boards vertically? Where the washboard is split, would one use an angled edge or overlapping rebates to keep water out?

 

[TimBennet]

I would appreciate your thoughts on mine.

They are going to be fine. The frame is massive enough to impart total rigidity to the acrylic, in the same way it's the frame that imparts the 'stiffness' to a vandal proof door or bus shelter. But you could have recessed the acrylic from the outside and simply stuck it in with some adhesive bedding. The extreme loads on the boards will always be inward and you wouldn't need any other fixings.

GRP is actually an ideal material (aesthetics aside) for washboard. To ensure they are adequately stiff without being too heavy, use some 12 or 15mm foam as a core, cutting it back from the margins, so the edges are solid and fit in the slots. It will never warp, swell or rot. Use a formica covered board as a flat panel mould, and with judicial use of some of a batten and parcel tape, you should be able to mould the rebate in one go.

 

[TimBennet]

Where the washboard is split, would one use an angled edge or overlapping rebates to keep water out?

Yes, rebates are the norm, with slopes an adequate second best.

The boards shouldn't be run vertical - you want the strength to be from side to side. Vertical grain would need massive reinforcement cross pieces behind.

 

[Wooden Boat Fittings]

I have some T&G oak flooring that could be put to use. However, the back face is ridged - I'd have to plane/sand it down, failing to find someone with a thicknesser. The edges would have to be routed back to 8 mm, I could do that. Why run the boards vertically? Where the washboard is split, would one use an angled edge or overlapping rebates to keep water out?

Sanderling's three wahboards had a simple ship-lap joint -- the first over the cockpit coaming, and the next two over the one below, all out of 3/8" ply. As said elsewhere, the top board could have been perspex to allow more light, but it wasn't like that when I bought her and I didn't feel the need to replace it.

Sanderling has three deepish washboards. Four shallower ones would probably have been better --

Mike
PS This picture was taken after I'd sold her -- her brightwork under my stewardship was always in better condition....

 

[coopec]

r. But you could have recessed the acrylic from the outside and simply stuck it in with some adhesive bedding. The extreme loads on the boards will always be inward and you wouldn't need any other fixings.

GRP is actually an ideal material (aesthetics aside) for washboard. To ensure they are adequately stiff without being too heavy, use some 12 or 15mm foam as a core, cutting it back from the margins, so the edges are solid and fit in the slots. It will never warp, swell or rot. Use a formica covered board as a flat panel mould, and with judicial use of some of a batten and parcel tape, you should be able to mould the rebate in one go.

Thanks for that.

I did consider mounting the acrylic on the outside and that would have been technically stronger but I decided it would look better mounting it internally.

Also I did consider making a f/g washboard but the ply is quite light - I can hold it at arm's length horizontally with no problem. I have reinforced all my hatches (including the companionway hatch) with divinycell and a heavy person could jump on them without doing damage.

View attachment 41157

 

[Ruffles]

Yes, rebates are the norm, with slopes an adequate second best...

Ours slope too much for rebates. Water would pool in the joint. But, you're right, slopes will cause the top board to protrude.

So I pondered a bit and made the boards square at the edges but sloping in the middle. Modelled it in bluetac to see what it looked like. Hard to explain but seems to work.

 

[Robert Wilson]

I have some T&G oak flooring that could be put to use. However, the back face is ridged - I'd have to plane/sand it down, failing to find someone with a thicknesser. The edges would have to be routed back to 8 mm, I could do that. Why run the boards vertically? Where the washboard is split, would one use an angled edge or overlapping rebates to keep water out?

Why plane/sand the "back" ridged wood.? Looks kinda interesting from inside the cabin!
Yes the edges have to be routed, or carefully sawn.
I ran the boards vertically purely because the off-cut lengths suited vertical - and suited the drip diverter too !!

I rebated the top and bottom boards then fixed (at the split) an angled edge which serves as a drip diverter and braces the vertical lengths. They are cross-braced top and bottom of each board (but not massively so - see above post)

Totally dry, but as yet not tsunami-tested.

I must RE-VARNISH before re-launch.!!

 

[ronmarson]

Neil,
Try 'Larry's' at the bottom of Richmond Road. He will cut whatever you want to any size.
Now I live in Galway I miss him.
Capt. RoN

 

[coopec]

Had I decided to make up a f/g washboard I doubt that I would have used foam to stiffen it. I have made up lids for my water tanks and have fluted them in the same way as vehicle manufacturers use flutes to stiffen up body panels. I haven't used much glass but they are very stiff (they would certainly take the weight of a person.) I suppose corrugated roofing iron uses the same principle.

 

[AntarcticPilot]

On my brother's boat he had some washboards made up from some mahogany - they looked lovely. However in warmer weather - we do get some occasionally - they do tend to warp quite badly. They straighten up again when cooled. I've not seen that with ply.

They only warped badly the first season - after that, they remained flat. I suspect the wood wasn't fully seasoned, causing the warping in the first year. They do look good, and are very sturdy!

Not sure about the wood - it is a red hardwood, but I suspect it is a mahogany look-alike, not mahogany, as it came from my local timber merchant, who mainly supplies the construction industry. It wasn't expensive enough to be real mahogany!

 

[timmygobang]

but must stay in place should the boat be knocked down, even if the companion way hatch is slightly open.

I don't mean to hijack this but how do you go about achieving this without making the washboards a very very snug fit. I was thinking of having some sort of pin on a lanyard to keep them in.

 

[AntarcticPilot]

I don't mean to hijack this but how do you go about achieving this without making the washboards a very very snug fit. I was thinking of having some sort of pin on a lanyard to keep them in.

There has to be a retaining device that locks the boards in place. I don't have one; if I were installing one I'd think about a bolt arrangement, or hasps on the washboards with a bar going to the bottom of the hatch. A pin on a lanyard might well be sufficient.