Rubbing strake damaged, how do I remove the old screws?

[Quidi Vidi]

Hi, a section of my rubbing strake was smashed off during the storms last winter and I am now finally getting around to sorting it out. The trouble I have is that the old screws won't come out, they are loose and turn and I can push and pull them about half an inch. Could they be countersunk bolts with a nut on the back? It all seems very odd, I thought it was going to be an easy job of just unscrewing them, oh silly me, is anything easy or straight forward on a boat!!

 

[Downsman]

" is anything easy or straight forward on a boat!!"............Occasionally...if you're lucky.

Can you see the thread clearly? Usually the thread on a bolt will be finer and easily distinguishable from a wood screw. Is your boat fibreglass hull?

 

[ghostlymoron]

From your picture gallery, yours looks like a 'biscuit tin' hull to deck join. This is the same as Hantu Biri the PBO project boat. There was an article on restoring the joint in PBO magazine a while ago which would give you an idea of whats going on. I would have a look inside and see if there are any obvious lumps which conceal a glassed in nut which I strongly suspect is what you've got. If so, the only way of removing them is by chiseling of the 'blisters' and removing the bolts in the normal way.

 

[Quidi Vidi]

Yes it is fibreglass and I think it is the biscuit tin joint although the PBO boat had a fillet of wood pushed up into the joint if I remember correctly. Mine doesn't seem to have this although I will have another look when I go down tomorrow. I had though of pull Ing them out as far as I can and then hacks awing them off, then pushing the remains into the void. I would then. Have the problem of what do I screw the new screws into? There are other screws that fasten the hull and deck joint under the rubbing strake and I had thought that they all just screwd into the GRP or perhaps a wooden backing that I can't see.

 

[Downsman]

I've only got limited experience helping someone else sort out his rubbing strake, but I recall his was secured with bolts and captive nuts. The nuts were on small individual 'plates' I imagine to make it easier to glass them in position. I do recall it meant peeling the head lining away along the edges and cutting away fibreglass to get at the plates/nuts, some of which had come adrift, causing the problem which you have, ie: the nuts turning.

 

[Quidi Vidi]

I've only got limited experience helping someone else sort out his rubbing strake, but I recall his was secured with bolts and captive nuts. The nuts were on small individual 'plates' I imagine to make it easier to glass them in position. I do recall it meant peeling the head lining away along the edges and cutting away fibreglass to get at the plates/nuts, some of which had come adrift, causing the problem which you have, ie: the nuts turning.

Thanks, that makes sense and would appear to be my problem. I really don't want to start dismantling and chopping to rectify the problem, does anyone have a plan B please, I can only think of cutting off the heads of the bolts and drilling new holes somehow.

 

[Lakesailor]

Rather than reinstate the rubbing strake in the original manner how about this?

Pull the head as far as you can and cut off (angle grinder and 1mm blade?)
Cut out the section of strake.
Then make proper scarf joints for a new piece of strake.
Fill any cuts in the grp and cut of the rest off the bolts, push though and fill those holes.
Then epoxy the repair piece in bonding to both grp and the scarf face.

Yes it may be difficult to remove in the future, but it isn't it a bit tricky at the moment?

 

[dancrane]

Probably not strictly relevant, but may I offer you a long, slow account of my recent keelband replacement? Here it is: http://www.ybw.com/forums/showthrea...ve-to-replace-a-keel-band&highlight=keel+band

I too was concerned what the screws were based in; some I found, turned ad nauseum without biting or gripping, so I wasn't sorry to remove them, then fill their holes and start again. Not so relevant if your retaining bolts are definitely screwed into unseen metal fastenings, because mine were just screwed into the GRP...

...but having observed the weak connection small screws create, I decided to combine them with a lot of exceedingly strong epoxy...belt & braces, screws & glue. Solid so far!

 

[neilf39]

I had the same thing on a Vivacity 650. For those that did not come out I hacksawed the head off and punched it through as you could not get to the back where the nuts were glassed in. The rolled into the bilge. To fit a new strake I drilled 9mm holes and used rivnuts to take M5 bolts. Rivnuts can be fitted from the outside but you need to know the thickness they go into so you can compress them with the tool. I had to recess mine a bit but as the strake bolts were not the ones holding the deck to hull it did not matter that they did not do anything to join the hull to deck.

 

[Quidi Vidi]

Rather than reinstate the rubbing strake in the original manner how about this?

Pull the head as far as you can and cut off (angle grinder and 1mm blade?)
Cut out the section of strake.
Then make proper scarf joints for a new piece of strake.
Fill any cuts in the grp and cut of the rest off the bolts, push though and fill those holes.
Then epoxy the repair piece in bonding to both grp and the scarf face.

Yes it may be difficult to remove in the future, but it isn't it a bit tricky at the moment?

Thanks for the suggestion, I don't mind if it's difficult to get off as I don't envisage me ever needing to remove it again in mine or the boats lifetime. I've heard that teak is difficult to glue/epoxy because of the oils in it, is this true?
The strake has been removed and the bits left are already scarfed so this might be a plan.

 

[Quidi Vidi]

I had the same thing on a Vivacity 650. For those that did not come out I hacksawed the head off and punched it through as you could not get to the back where the nuts were glassed in. The rolled into the bilge. To fit a new strake I drilled 9mm holes and used rivnuts to take M5 bolts. Rivnuts can be fitted from the outside but you need to know the thickness they go into so you can compress them with the tool. I had to recess mine a bit but as the strake bolts were not the ones holding the deck to hull it did not matter that they did not do anything to join the hull to deck.

Thanks, I've not used rivnuts before so I will look into this.

 

[conor54]

If you cut of the old screws/bolts you could then poke some narrow wire into the space behind to see how large it is. If it is quite small then you could inject some thickened epoxy mixture into it and once set then screw into that. Perhaps initially put in some water with food coloring to see if the space is open to the bottom...in which case perhaps the epoxy would all run out.

If that is the case then you could try injecting a little expanding foam to fill the space and let it go off. Then see post 2 on this "http://www.ybw.com/forums/showthread.php?177819-Bolting-fittings-through-a-balsa-core-deck" about hollowing out a space behind the original hole and fill up with the thickened epoxy.

Have fun,

Conor.

 

[Lakesailor]

If you don't know what the void is behind (like with no bottom) you could end up pumping loads of epoxy in. However thick you make epoxy it will slump before it goes off.
I don't see why there is the requirement to bolt or screw the strake on. It's much easier to bond it on. You could use a marine construction adhesive like Sabatack 750 XL and epoxy the scarfs.

 

[Tranona]

If you don't know what the void is behind (like with no bottom) you could end up pumping loads of epoxy in. However thick you make epoxy it will slump before it goes off.
I don't see why there is the requirement to bolt or screw the strake on. It's much easier to bond it on. You could use a marine construction adhesive like Sabatack 750 XL and epoxy the scarfs.

depends on how much curve there is in the new section. Fastenings might be needed to pull the new section in. Alternatively the new strake could be laminated to shape before attaching.

 

[pmagowan]

You could use a hole saw slightly bigger than the head of the bolt and cut them out this way. Then you simply insert a new bolt beded in epoxy, wait til it goes off and then reattach the rubbing strip which can be scarfed into the old strip. The nut can be hidden in a plug in the strip.

 

[Lakesailor]

depends on how much curve there is in the new section. Fastenings might be needed to pull the new section in. Alternatively the new strake could be laminated to shape before attaching.

There is that. Steaming could create the curve.