Water Rising Or Boat Sinking

Lakesailor

Lakesailor

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Looking from my lounge this morning my little 18ft boat seemed to be down at the stern and wasn't moving as fluidly on the chop as normal.
After lunch I went out to have a look and discovered that the bottom transom pintle had dropped off, leaving a loose rudder and three holes below the waterline. (above in this pic as the boat pitches)

Rudder01.jpg


The violent chop of the past few days must have created a lot of sideways forces on the pintles and slackened off the nuts holding the bolts.

Windymere_5.jpg


I've bashed some tapered dowels into the holes for the moment until the new part arrives (pic from above so a little disorienting)

Rudder02.jpg


They seem to have stopped water coming in for the time being.
Rudder03.jpg


So when I fit the new one how do suggest I secure the nuts. I had put some Sikaflex on the threads when I retightened them last time, but this obviously wasn't enough.
Do I use spring washers, or try to make some locknuts (it's a bit tricky to get at with 2 hands.)
 
If it is tricky to get at from the inside, I find a backing plate with something to hold the nylocks in place works well. Generally a thick bit of marine ply with countersunk holes and grooves for some stainless bar works well. You can then tichten the bolts from the outside in one swift action.

I hope that makes sense.
 
secure each set screw with two nuts tightened against each other as the method for removing studs "stud box" obviously the screws need to be long enugh to accomodate, removes the prospect of spring washer corroding, or the tight threads of a locknut to bolt up. of course this remedies the bolts as the weak link and therefore the pintle may be the next point to break, so be shure to use a substantial one. and so on.
by the time that you have eliminated the succesive weekest links you may need a bigger hull to support the overengineerd transom.
but seriously hope that the stud box suggestion proves to be worthy.
ps.may be comming to windameer this sunday weather permitting /forums/images/graemlins/wink.gif
 
accept my appologies for my poor spelling "windameer" should be windemere
my native english is NOT my strong point /forums/images/graemlins/blush.gif
 
Get some really big "penny" washers to go under the nuts so you can tighten them up really hard without squashing the wood between the grp layers. Nylocs are only going to help if they start to undo.
 
I don't think I'll be able to get both hands in to lock the nuts of against one another.

The stainless nylocks look like a good option. I thought we had tightened the nuts well the last time, with one person outside with screwdriver and me in the locker with a spanner. I think this particular installation allows a lot of leverage on the lower pintle. Any slight give in the assembly giving a bit of looseness for the wave action to work on. I always make off the tiller as I don't like the rudder thrashing about, but it does transfer movement to the mountings. The other alternative is to ship the rudder everytime I leave the boat, which is a bit of a pain in the neck.
 
Gosh good job you can see it from home, mine is eighty miles away but i dont leave the rudder on (It'll lift off and float away when the tide goes down) anyway it's high and dry for the winter.

I agree with most of the suggestions. Nyloc nuts, or Aerotite nuts, 2 nuts locked together (one a half nut perhaps) but I would have thought some Sikaflex on the threads would have stopped them coming off. Loctite maybe but I'm not sure if it is totally water proof.
I like the idea of a plate to spread the load, if not then definitely use penny washers.
 
Could do a bit of both

get a plate and tackweld the nuts onto the back of it ... a tackweld should be enough for you to tighten up sufficiently and the nuts cannot undo themselves .... also - the load is spread across the plate (given sufficient thickness!)
 
I used to weld nuts onto Mini engine mounts. Saves about 20 minutes taking engines out. Not sure in this instance as the constant working of the rudder on the pintles may just wind the setscrews out of the nuts.
My favourite solution would be the locknuts. It's just a question of whether I can get into the locker (and out again) given that I have a bit of a trapped sciatic nerve.
Next favourite is the SS Nyloc nuts.
I'll definitely use a bigger washer, maybe a pad with 3 holes in.
 
I think part of the probem may have been using countersunk screws with a screwdriver slot. Can you use hexagon head bolts? If they must be countersunk, then hexagon socket heads would be better as you can then use a bar and hex key to get more purchase on them. I would also add my vote some sort of locking device.
Allan
 
Fit it as you normally do, degrease the inside thread that is exposed apply Loctite 601 retainer, will not undo unless very hot. or their 270 stud lock or put a lock nut,either method should give you peace of mind.
 
[ QUOTE ]
I don't think I'll be able to get both hands in to lock the nuts of against one another.

[/ QUOTE ]
try wedging an open end spanner between first nut and hull once it has innitially been tensioned that will then leave you free to apply second nut and tigeten up /forums/images/graemlins/wink.gif
 
lucky you spotted it in good time. i would have a good look at the top pintle and its fastenings as well .They must have suffered some considerable strain with the rudder moving about.
 
Its my opinion as an ex-engineer (well design engineer) that most peeps just don't tighten things up enough.

In this case, using slot head cs bolts meant that there was no way using an ordinary screwdriver, that these were ever tight.

Old engineers trick, use a sharp centre punch to put a couple of 'dots' on the top of the nut. Or in this case on the pintle plate right next to the open ends of the screws slots, to stop the screws turning whilst the nuts are tightened up inside (and then dotted)
 
Stretching the threads depends on the pieces you're clamping being very solid. GRP with a wooden pad encased and sikaflex bedding of a nylon fitting don't really give enough resistance to pull on the threads enough. I'm going to rely on locking the threads either with nylocks or locknuts, as suggested.
 
Bear in mind, that if the screws are a loose fit in the transom, the pintle will move sideways, if stressed hard. This movement will loosen the screws.

I would make sure the screws are a tight fit in their holes.

Philip
 
Have you tried 'stud lock' can be bought from most car shops, used in car braking systems etc. Really good stuff provided component parts are clean,
 
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