Captive nuts?.....or not!

[Dtwo1946]

Hi

I've got a Hille 530 Coaster. The height adjustment on the front seat pedestals relies on one alloy tube rising and falling inside another. Yes..you've guessed it! They're seized.

The only surefire way to free them is to remove the seats, pedestal and all, from the boat. I'm nervous about this. I've not done it before. They're secured to the deck by six or eight large screws. There is no access to the underside of the deck.

Is it common practice for boat manufacturers to fit some sort of arrangement that includes captive nuts or a timber or metal backing plate? I don't want to go through cutting a hole in the deck to refit them if this is not the case.

Any advice will be greatly appreciated.

 

[kashurst]

tricky question - no two boats are ever the same. They also tend to get built by people who have no plans to take it apart again. If the boat is any age and there are captive nuts you can guarantee they are not captive anymore - most specifically the last one you need to undo. So if you want to unbolt the pedestal you might get lucky but plan to remove part of the ceiling below. Also trying to free off two alloy tubes that are corroded together is virtually impossible (trust me on this one - tried it on a previous boat)

Can you unbolt/unscrew the seat base from the pedestal. If it's too low use a block of wood to raise the seat base. If its too high make a wooden step in front of it cunningly designed as extra storage. No one will ever know and you will have the satisfaction of a job well done rather than weeks of desperate hacking/banging/heating (I still have flash backs when I smell WD40)

 

[Stewart46]

there's every chance that they could just be large self tapper's in which case there's no nuts at all

 

[Dtwo1946]

tricky question - no two boats are ever the same. They also tend to get built by people who have no plans to take it apart again. If the boat is any age and there are captive nuts you can guarantee they are not captive anymore - most specifically the last one you need to undo. So if you want to unbolt the pedestal you might get lucky but plan to remove part of the ceiling below. Also trying to free off two alloy tubes that are corroded together is virtually impossible (trust me on this one - tried it on a previous boat)

Can you unbolt/unscrew the seat base from the pedestal. If it's too low use a block of wood to raise the seat base. If its too high make a wooden step in front of it cunningly designed as extra storage. No one will ever know and you will have the satisfaction of a job well done rather than weeks of desperate hacking/banging/heating (I still have flash backs when I smell WD40)

Thanks

I'm nipping down to the boat today to check out the 'block of wood' solution. The main problem is that the helm seat is too low. I can't see over the bow! This could cause the odd flutter in the chests of Japanese car ferry and oil tanker captains down at Tees mouth when I'm buzzing about pestering mackerel. Also it could affect my nose! One of the Tees pilots lives across the road from me and he may come across and punch me on it.

Trouble is, the fitting beneath the seat has a sliding mechanism for moving the seat back and forth and yesterday I couldn't see a way of separating it from the pedestal (the seat proper does detach). It looks as though it would foul a wooden block.

Everybody else in the World agrees with you that separating the two alloy tubes should only be attempted if you have a 50 tonne press in your kitchen or are built like the incredible hulk.

 

[Dtwo1946]

there's every chance that they could just be large self tapper's in which case there's no nuts at all

If they are I can see the sense of relief driving me straight to the pub for a pint or two.

 

[PCUK]

Take one out and see what they are. You can always glue it back if you can't get the rest out. I can supply you some stainless jack nuts (cavity wall type nuts but very strong) if you find they are loose 'captive' nuts.