Genoa rail bolts, stainless?

[DHV90]

Hi everyone,

Currently resealing deck fittings on a Hustler 36 and the original genoa track bolts are knackered, bent and the ends have been bolt croppered so the threads are too mashed to get the nuts back on! And any way, the nuts appeared to be 8.5mm or so across the flats so couldnt even get any purchase with a ring spanner. Im going to replace the lot and was wondering what the best material would be. Is the risk of galvanic corrosion enough to warrant something other than stainless steel?

Dan

 

[vyv_cox]

There should be only a minor risk of galvanic corrosion on deck, particularly if you use a decent sealant to exclude water. I doubt if more than a few percent of boats use anything other than stainless steel for this job.

 

[DHV90]

Fantastic, trying to do a half decent job with butyl tape so that should all be good. thanks for the help

 

[Boathook]

I use arbomast br around the bolt/screw head to try and stop any problems with s/s and aluminium corroding together.

 

[DHV90]

Do you think it's worth trying allen bolts or is sticking to flat head the best option?

 

[William_H]

I replaced my traveller track recently. The track was provided with little plastic inserts to go around the shaft and under the countersink of the 4mm bolts. Yes the stainless steel will be contacting the ali track unless you can separate the 2 with a teflon type tape or Duralac paste. certainly stainless steel is the bolt to use. good luck olewill

 

[macd]

Do you think it's worth trying allen bolts or is sticking to flat head the best option?

Flat-head (which might mean plain slotted, cross-head or Allen) but obviously countersunk. This lends itself best to sealing against both leaks and galvanic contact, whether using butyl as you propose or some other medium. Butyl cones work especially well in such applications.

 

[VicS]

Hi everyone,

Currently resealing deck fittings on a Hustler 36 and the original genoa track bolts are knackered, bent and the ends have been bolt croppered so the threads are too mashed to get the nuts back on! And any way, the nuts appeared to be 8.5mm or so across the flats so couldnt even get any purchase with a ring spanner. Im going to replace the lot and was wondering what the best material would be. Is the risk of galvanic corrosion enough to warrant something other than stainless steel?

Dan

8.5mm A/F probably makes them ³/₁₆" Whit (or no8 UNC), but you will be replacing them with M5, which is 8mm A/F I should think,

Personally I not use tape for sealing. It is very important that there is a very good seal, leaving no crevice for water to penetrate, between the bolts and the deck or they will suffer from crevice corrosion.

 

[NormanS]

8.5mm A/F probably makes them ¹/₈" Whit, ³/₁₆" BSF (or no8 UNC), but you will be replacing them with M5, which is 8mm A/F I should think,

Personally I not use tape for sealing. It is very important that there is a very good seal, leaving no crevice for water to penetrate, between the bolts and the deck or they will suffer from crevice corrosion.

Not sure where Vic is getting his information, but I've just gone and measured a 3/16" Whitworth nut, and it is 8.2mm AF.

 

[vyv_cox]

Not sure where Vic is getting his information, but I've just gone and measured a 3/16" Whitworth nut, and it is 8.2mm AF.

Ah, but is it a metric Whitworth or an Imperial one?

 

[VicS]

Not sure where Vic is getting his information, but I've just gone and measured a 3/16" Whitworth nut, and it is 8.2mm AF.

From a very useful table, but which to be fair is a table of spanner jaw sizes, at http://www.sat.dundee.ac.uk/~psc/spanner_jaw.html

Exactly what the old ones where is probably of no concern to the OP but since you obviously disagree with my suggestion what size are they in your opinion.

Ah, but is it a metric Whitworth or an Imperial one?

An inferior one I should think.

 

[xeitosaphil]

Do you think it's worth trying allen bolts or is sticking to flat head the best option?

Depends really if there is any chance you may have to remove them at a later stage. Allen bolts (or Socket M/Screws) are ok if not seized into the countersink with the salt, but I have had a situation where the allen key has spun around in the socket leaving a round hole with no means of getting it out. It's quite possible using 316 S/S (which tends to be softer than the steel allen key itself) leaving no other way of removing it other than cutting the nut off, which is ok if you can get at it.

At least with a slot head you can usually find another way to remove it.

My choice would be to stick with countersunk slot headed.

 

[lw395]

Depends really if there is any chance you may have to remove them at a later stage. Allen bolts (or Socket M/Screws) are ok if not seized into the countersink with the salt, but I have had a situation where the allen key has spun around in the socket leaving a round hole with no means of getting it out. It's quite possible using 316 S/S (which tends to be softer than the steel allen key itself) leaving no other way of removing it other than cutting the nut off, which is ok if you can get at it.

At least with a slot head you can usually find another way to remove it.

My choice would be to stick with countersunk slot headed.

Allen and Pozi CSK are much more receptive to being removed with a left handed drill bit than slotted.

 

[NormanS]

From a very useful table, but which to be fair is a table of spanner jaw sizes, at http://www.sat.dundee.ac.uk/~psc/spanner_jaw.html

Exactly what the old ones where is probably of no concern to the OP but since you obviously disagree with my suggestion what size are they in your opinion.

I'm not giving opinions here. I'm merely giving facts measured in reality, not from internet tables. Go and check a 3/16" Whit nut for yourself, if you don't believe me. Unless you measure a pre WW2 nut, you'll get the same result as me.

 

[VicS]

I'm not giving opinions here. I'm merely giving facts measured in reality, not from internet tables. Go and check a 3/16" Whit nut for yourself, if you don't believe me. Unless you measure a pre WW2 nut, you'll get the same result as me.

Sorry I was not disputing that your nuts are only 8.2 mm.

You said you were not sure where I was getting my information from, so I posted the link.

A 8mm AF spanner wont fit on a 3/16" Whit nut and 9 mm (ring) spanner will not grip it. Fact! Checked in reality.So I am still suggesting that the nuts on the OP's track were probably 3/16" Whit, but short of checking the thread as well I say no more than, "probably".

Do you actually have any useful contribution to make or are you merely looking to start trivial arguments about irrelevant details.

 

[NormanS]

Sorry I was not disputing that your nuts are only 8.2 mm.

You said you were not sure where I was getting my information from, so I posted the link.

A 8mm AF spanner wont fit on a 3/16" Whit nut and 9 mm (ring) spanner will not grip it. Fact! Checked in reality.So I am still suggesting that the nuts on the OP's track were probably 3/16" Whit, but short of checking the thread as well I say no more than, "probably".

Do you actually have any useful contribution to make or are you merely looking to start trivial arguments about irrelevant details.[/QUOTE).

Well, pardon me for breathing, but NOW you are agreeing with me that the bolts are probably 3/16"Whit, whereas EARLIER you were saying that they were 1/8"Whit. (Your post No8).

However, please don't get your knickers in a twist over it. We are all trying to help each other here, and it would be a shame if the OP was inadvertently given misleading information.

 

[VicS]

Sorry I was not disputing that your nuts are only 8.2 mm.

You said you were not sure where I was getting my information from, so I posted the link.

A 8mm AF spanner wont fit on a 3/16" Whit nut and 9 mm (ring) spanner will not grip it. Fact! Checked in reality.So I am still suggesting that the nuts on the OP's track were probably 3/16" Whit, but short of checking the thread as well I say no more than, "probably".

Do you actually have any useful contribution to make or are you merely looking to start trivial arguments about irrelevant details.[/QUOTE).

Well, pardon me for breathing, but NOW you are agreeing with me that the bolts are probably 3/16"Whit, whereas EARLIER you were saying that they were 1/8"Whit. (Your post No8).

However, please don't get your knickers in a twist over it. We are all trying to help each other here, and it would be a shame if the OP was inadvertently given misleading information.

Bit of clumpsy copyiny and editing. Now deleted refernc to 1/8W. You can untangle your nuts from your underwear now.