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- 29/03/2010 at 7:37 am #4126laurie chalkMember
Can anyone please suggest the right thickness and type of wood for a rubbing strake on my Mk1 grp. I have seen them recently made of teak and iroko, and they look about 1″ thick.
W185829/03/2010 at 12:20 pm #9064adminMember
In refurbishing my GRP Mk 11 I removed the rubbing strakes and I reckon I saved a couple of kilos in weight (not counting the screws that held them on. I took them off because I was about to paint the boat and wanted to offset the weight of the paint. The wood was a dark hardwood, more likely to be iroko than teak. Unless you keep teak well oiled/protected it will go silver-grey as it weathers.
Thickness is only a function of the fixing method (ie to give you enough depth to counterbore and fill the screw-holes). I would be tempted to go for a thin but resilient material like a plastic strip and glue it on. I recently fixed beta-strip to the bilge-keels using a waterproof contact adhesive and have been impressed how well it has fixed the plastic to the GRP. Mind you I have yet to try it out in the water…29/03/2010 at 5:18 pm #9066magiccardvinceMember
the strake on our mk11 is 19mm thick and was recycled from a hardwood staircase handrail.
Vince W758403/04/2010 at 7:40 pm #9090
I’ve just bought some iroko – 30mm x 12mm was the size I ordered. So far I’ve only offered it up against the gunwhale and, to me at least, it looks about right.
(I am also taking the opportunity to fit ‘P clips’ – from Rob at Canvas Windmill – to secure my tent bridle, rebated into the iroko strip and then sandwiched between the gunwhale and the rubbing strake).
Shuna03/04/2010 at 7:45 pm #9091
@Mike Summers wrote:
I recently fixed beta-strip to the bilge-keels using a waterproof contact adhesive and have been impressed how well it has fixed the plastic to the GRP. Mind you I have yet to try it out in the water…
Mike, you might be interested (relieved?) to hear I did the same job a year ago and the beta strip is still as firmly attached as when I did it. Our boat had a fair amount of use last year including over a week afloat on a mooring. I too was very impressed how well it adhered to the grp.
Jonathan04/04/2010 at 9:46 am #9093
I would not skimp on thickness, two boats coming together can make a big hole and the thicker,about the 19mm talked about is much better.
If you go too thin,the wood has much more chance of braking with contact and that will make you more work for what maybe, small contact.
Thicker can also sand out any damage and so last longer.
When you fix to wood to the boat and drill into any tank,dont forget too put some glue or epoxy in the holes to help seal the bouyancy.
One last thing, if you can get the gunwale in one length or scarf lengths together to make one whole length it will go on to the boat much better.
C P 😉04/04/2010 at 6:13 pm #9095
Seems like I might have under-spec’d the thickness – my only defence as a committed non-racer is that I’m a bit more concerned with (hopefully gentle) encounters with pontoons, jetties etc. Anyway hopefully it should be better than no rubbing strake and at least I know my tent bridle will be secure.
Colin – any advice on what glue you would recommend?
Jonathan07/04/2010 at 8:42 pm #9109SwiebertjeParticipant
Mine is screwed on with SS countersunk self threaders. The screw heads are plugged over with the same wood. Just make sure the screw holes in to the buoyancy tanks are well sealed, for example with Sikaflex. Plugging the screw heads is easy with polyurethane construction glue (the type that foams). Hold the plugs in place with some adhesive tape while the glue sets. Then sand the plugs and varnish. It is as easy as it sounds. The P-clips on my boat are fixed using the same screws that are used to fix the rubbing strakes.
Any extra weight should be taken of the lead beneath the thwart. A certified boat has to meet minimum weight requirements and if you remove the screws from your rubbing strakes you may have to add lead to the thwart.08/04/2010 at 4:20 pm #9119
No glue, only for the screw holes. Epoxy is good as that Sixaflex stuff is good for some things but can hang on when you don’t want it too.
Use with care!
If you make the rubbing strake, drill all the holes and varnish or oil if its teak or iroka it is then a stand alone item.
You can then take it off if damaged or at seasons end to maintain.
C P 🙂08/04/2010 at 7:00 pm #9121BluTakParticipant
Last year I put on a rubber fender. I used Wilks PVC 50 @ £5.51/metre and bought the aluminium insert strip at a local steel stockist for £2.61/metre. Look up the Wilks website – I did some research and it was by far the cheapest. You stretch it with a spanish windlass when you put it on and it worked fine so I now hope to use fewer fenders. I know wood looks better but I’m hoping PVC is more practical. I also used their pvc cord to fill the holes in. The cord can be smaller than the screw heads as the heads “squash” through. Robert11/04/2010 at 6:57 pm #9138JonathanMember
Thanks for the advice not to use glue, should make things a bit easier.
I’m planning to treat with teak oil – does anyone know if there is any difference between the household and marine oils other than the latter being 4x more expensive?
Jonathan11/04/2010 at 7:35 pm #9140SwiebertjeParticipant
Household teak oil is used for maintenance of furniture. The teak oil used in marine applications is more like a varnish. It hardens in to a coating. I don’t know what sort of oil or mixture is used exactly, but I would think it to be closer to linseed oil then to a furniture maintenance oil.11/04/2010 at 8:45 pm #9141
Have a look at Tung Oil, maybe of use !
C P 🙂01/06/2010 at 1:14 pm #9358JoJoMember
I have been following discussions on rubbing strakes. The final touches on my refurbed MkII GRP – I guess should be a rubbing strake – otherwise my nice new paint work could be quickly scraped – like most people – I am on a budget and want to do the best possible job for the least cost. I have seen the PVC strake available through Wilks – P50 comes in a 9m roll 1m – too short or a 15m roll – 5m too long – and costing near £100. One thread suggested Trident UK do something but I cannot fnd this on their site.
I read about wooden strakes – where do these come from? are they relatively easy to fit? and how much is it going to cost?01/06/2010 at 11:14 pm #9361adminMember
Following on from my earlier reply, howsabout the rigid and flexible lipping mouldings offered by this outfit?
It could be glued on with no visible fixings, is tough (PVC), the colour range is a bit limited but if you like black or white it may make you happy (wood only comes in “wood” colour) and it is light and flexible.
Just a thought.
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