Liverpool Flappy Ruder Bolt Size

[reg]

Over the holiday I developed a case of Liverpool Boat flappy Rudder syndrome (LBFRS)

Questions:

Can these be replaced whilst in the water?

Does anyone know the correct  bolt sizes and what quality should i be looking at?

Is it worth eventually having, as has been suggested elesewhere, the rudder welded?

 

I only need to effect a repair to get me through to spring or summer when I will have the boat out for blacking.

many thanks for any valid replies.

 

 

[dor]

The rudder is held by two through bolts and one that goes through a nut welded on the outside.  The through bolts don't really do anything to stop the flapping, this is done by the bolt going through the welded nut.   This bolt, between the other two,  will also have a locknut on it.  So to stop the flapping, you need to slaxken off the locknut, then tighten the bolt up as hard as you can - this means very tight. Then re-tighten the lock nut.

It is theoretically possible to do it in the water if you have long arms, but at this time of year your fingers will freeze before you have even found the bolt.  The best thing for a temporary fix is to go to a marina with a slipway and trailer that will pull the boat out of the water for an hour or two, leaving it on the trailer.  This usually costs about £80 or so (probably more in the south).   Then when you want to fix it properly, re-tighten the middle bolt, and then put a good squirt of weld on the top of the rudder.  About 10mm of weld should be sufficient.  It is easy to grind off at a future date if you need to remove the rudder.

I think the bolts are 19mm A-F

[reg]

4 minutes ago, dor said:

The rudder is held by two through bolts and one that goes through a nut welded on the outside.  The through bolts don't really do anything to stop the flapping, this is done by the bolt going through the welded nut.   This bolt, between the other two,  will also have a locknut on it.  So to stop the flapping, you need to slaxken off the locknut, then tighten the bolt up as hard as you can - this means very tight. Then re-tighten the lock nut.

It is theoretically possible to do it in the water if you have long arms, but at this time of year your fingers will freeze before you have even found the bolt.  The best thing for a temporary fix is to go to a marina with a slipway and trailer that will pull the boat out of the water for an hour or two, leaving it on the trailer.  This usually costs about £80 or so (probably more in the south).   Then when you want to fix it properly, re-tighten the middle bolt, and then put a good squirt of weld on the top of the rudder.  About 10mm of weld should be sufficient.  It is easy to grind off at a future date if you need to remove the rudder.

I think the bolts are 19mm A-F

Many thanks for the excellent reply, much appreciated.

I take it that in a worse case scenario that even if the middle welded nut bolt should fail then with the arrangement described the 2 other bolts would  retain the rudder in place?

If that is the case then I would be reasonably happy to limp through to spring when I dry dock. My main concern was that if the bolt should fail that I would loose the rudder it would appear from your description that that would be unlikely if I treat the rudder gently.

As a safety fall back I am thinking of investing in a cheapish set of full length waders circa £40 any suggestions on a decent pair for that price would be welcome. i would only envisage light occasional use from these so top quality not really required.

[Alan de Enfield]

17 minutes ago, reg said:

As a safety fall back I am thinking of investing in a cheapish set of full length waders circa £40 any suggestions on a decent pair for that price would be welcome. i would only envisage light occasional use from these so top quality not really required.

Waders are fine if your arms reach below your knees.

However, if you need to bend down then the top of your waders (the chest part) can actually dip into the water and scoop up lots of the cold-wet-stuff, you will then need to take them off (in the water) as you will not be able to get out of the water due to the additional weight.

If you happen to fall over whilst wearing chest-waders the air gets trapped into the feet/legs and you cannot then get the feet down to stand up, you will need to take them off in the water before you can stand up.

Dangerous things waders.

Been there. done that.

I wouldn't bother with waders for 'working on the boat', but are OK for dragging a grapnel/magnet along the bottom if your rudder has dropped off.

Your money - your choice.

Edited January 2, 2018 by Alan de Enfield

[reg]

1 hour ago, Alan de Enfield said:

Your money - your choice.

Choice made, greenie given,£40+ saved. many thanks

Edited January 2, 2018 by reg

[ditchcrawler]

I have a pair on the boat, they are 15 years old now and still in the packet, probably perished

[chubby]

I have the same issue . I blacked my boat in late summer and ought to have got it welded . But didn't but will next time as the flappy rudder is a bit annoying. The rudder cannot come off as the bigger bolts at the top and bottom secure it . The " pinch " bolt in the middle is what is supposed to prevent it working loose but it doesn't because it's basically a crap bit of boat building . I think you should just get it welded when it's next out the water . Even if u manage to tighten that middle bolt it's likely to work loose again .

[X Alan W]

22 hours ago, dor said:

 

I have come across M10 & M12 bolts used not sure if m10 was original & m12 was used after drilling  out to cure wobble which it wouldn't a grade 8 or better quality steel bolt if replacements are required the use of multi tang lock washers & self locking nuts will help in keeping the fastenings tight

 

[dor]

To the post above:  It makes it look as though you are quoting me, but of course you are not.

19mm A-F is M10

[billh]

18 minutes ago, dor said:

To the post above:  It makes it look as though you are quoting me, but of course you are not.

19mm A-F is M10

19mm(=3/4")A/F is 12mm bolt diameter, usual M10 is 17mm(c11/16") A/F

[dor]

2 minutes ago, billh said:

19mm(=3/4")A/F is 12mm bolt diameter, usual M10 is 17mm(c11/16") A/F

Hmmm - I think you are right.  The chart I have gives 19mm for M10, but having had a quick google, it seems that 17mm is more common for M10.  However it seems there are several "standards" which vary!

[reg]

13 hours ago, ditchcrawler said:

I have a pair on the boat, they are 15 years old now and still in the packet, probably perished

WADERS One of those ideas that seem like a good idea at the time much like my Aldi satellite dish which has been in my locker for about 5 years(Trying very hard not to mention Aldi Ecofan so won't )  

BOLT size so it looks like it's M10 then? Do you know what standard I should ask for to prevent rusting but remain strong? I'm thinking of replacing all 3 so will pre  purchase before dry docking. 

WELDING Seems like the best solution long term. 

 

 

Edited January 3, 2018 by reg

[Canal321]

4 hours ago, reg said:

(Trying very hard not to mention Aldi Ecofan so won't )

But as we all know, you just did... 

[reg]

1 hour ago, Canal321 said:

But as we all know, you just did... 

Oh no I didn't 

[X Alan W]

10 hours ago, dor said:

To the post above:  It makes it look as though you are quoting me, but of course you are not.

19mm A-F is M10

19mm spanner size is usual for M12 Fastenings 17mm spanner is usual for M10 I wasn't quoting you as also seen in the liverpool boat rudders assem & fastanings  Welded ,3/8 whitworth nuts welded on tbe with rudder shaft dimpled & bolt end ground to a point & tightened into the dimples mst sizes of bolts from 10mm through 14mm & imperial bolts in whit & UNC/UNF threading 3/8ths through 5/8ths seems the first bolt to hand was pressed into service Not an impressive fixing method any way