Fitting teak grab rails

[Fascadale]

I need to fit some grab rail/handles to the inside of my MAB.

I seem to remember reading here that there was a "right" way to fit these and 'wrong" way. Something to do with either bolting through from above or screwing from below.

Advice would be appreciated as would suggestions as to where the correct items might be purchased.

Thanks

 

[Blueboatman]

Well one way is to fit matching handraisl top and bottom. If they are predrilled for wooden plugs then you will of course have to stagger them fore and aft a few mm to avoid the respective screws meeting.

Strong and simple, but is there a grp cabin liner and possible air gap on the underside or just paint/foam/vinyl?

 

[auditdata]

If it needs to hold the weight of a man, bolt it!

 

[KenMcCulloch]

You can buy such things ready fabricated but it's easy and cheap to make them yourself. You just need an old geezer with a grey beard and some sawdust between his teeth to point you in the right direction. Easiest in some respects as blueboatman says is to fit matching sets of grab handles inside and out with machine screws through both. Give me a call.

 

[Fascadale]

Strong and simple, but is there a grp cabin liner and possible air gap on the underside or just paint/foam/vinyl?

I want to fit them internally on the main bulkhead, so there will be easy access behind them

 

[VicS]

I want to fit them internally on the main bulkhead, so there will be easy access behind them

Down below then they are just hand holds...... not for someone to hang onto or clip their harness to to prevent themselves going over board.

I would screw them on through the bulk head ......

If you though bolt them you will need counterbored holes and plugs and may end up with nuts that are difficult to hide

For extra strength it may be possible to double up on (some of) the screws

 

[William_H]

Grab rails

You can of course fit wood screws from behind so nothing is seen. However I think a good SS bolt right through will be strongest and look the part. It does need to be well attached as said.
I think I would buy the grab rails rather than try to fabricate.
good luck olewill

 

[al.carpenter]

Hi there. Screwing a hand-rail? You have Faith.... Bolt through, EVERY time with backing/packing plate and a lot of "thinking" has to be done before regarding application/report/spreading of forces... if you want to do a proper job of course. Safe sail all. Al

Blue boatman wrote...

-Well one way is to fit matching handraisl top and bottom. If they are predrilled for wooden plugs then you will of course have to stagger them fore and aft a few mm to avoid the respective screws meeting.

My advice, two screws close to each other in the same plane or not (more so a few mms!!!) are "chewing" fibres and a recipe for failure... stupid thing to do...

 

[Swg]

All advice here looks reasonable except the naysaying missionaries who don't approve of screwing from below. Variety!

 

[NormanS]

If it's to be a grab rail that you might grab, bolt it. No contest.

 

[Deleted member 36384]

If it's a wood to wood bond then glue them in place and just use screws from the top to clamp up while the glue sets. If you can support the handle while the glue sets then there is no need to screw at all.

The hand rails on the bulkhead in my saloon are glued in place and screwed with small crews just to locate them. They are very strong indeed and have frequently taken the weight of a man (a fat man at that).

 

[al.carpenter]

If it's a wood to wood bond then glue them in place and just use screws from the top to clamp up while the glue sets. If you can support the handle while the glue sets then there is no need to screw at all.

The hand rails on the bulkhead in my saloon are glued in place and screwed with small crews just to locate them. They are very strong indeed and have frequently taken the weight of a man (a fat man at that).

Again, I would not advise on gluing a grabrail... you have to think and understand wood and how it works, its mechanical properties...
If you glue wood on wood (even more if it is wood on deroule plywood, which is likely to be the case for your bulkhead) it is guaranteed that even if you have used the best quality bonding agent, if you apply a 80kgs force parallel to the bulkhead on the two, three four or even six times 4cm2 of contacting fibres these will fail (even quarter sawn timber). Your glue will not fail, it is much stronger than cellulose etc... but the wood will. As a shipwright I break up glued wood nearly every day (not often structural... being a traditional boat builder) and sometimes it amazes me how easy it is to split apparently healthy and well structured straight fibres, so more in the case of plywood which is a vulgar "peeling" and has no strong bonding between fibres...
Every single bolt (even 5mm diam) you use will have hundreds of kilos of resistance, shearing or pulling... Some people are giving quite odd advice on here and will not be there to pick you up when you find yourself at the other end of your sailboat with your rail in your hand and a big bump on your head...

 

[Deleted member 36384]

Again, I would not advise on gluing a grabrail... you have to think and understand wood and how it works, its mechanical properties...
If you glue wood on wood (even more if it is wood on deroule plywood, which is likely to be the case for your bulkhead) it is guaranteed that even if you have used the best quality bonding agent, if you apply a 80kgs force parallel to the bulkhead on the two, three four or even six times 4cm2 of contacting fibres these will fail (even quarter sawn timber). Your glue will not fail, it is much stronger than cellulose etc... but the wood will. As a shipwright I break up glued wood nearly every day (not often structural... being a traditional boat builder) and sometimes it amazes me how easy it is to split apparently healthy and well structured straight fibres, so more in the case of plywood which is a vulgar "peeling" and has no strong bonding between fibres...
Every single bolt (even 5mm diam) you use will have hundreds of kilos of resistance, shearing or pulling... Some people are giving quite odd advice on here and will not be there to pick you up when you find yourself at the other end of your sailboat with your rail in your hand and a big bump on your head...

Yet mine have not failed and have supported my 86kg! Teak, glued and screwed. I don't disagree with the point you make though about bolting.

 

[al.carpenter]

Yet mine have not failed and have supported my 86kg! Teak, glued and screwed. I don't disagree with the point you make though about bolting.

Hi BoB, as soon as I have a few minutes to spare I will use my new camera and film the experiment since I have a few discarded grabrails in the workshop and we can test "scientificaly" their resistance... Will use a 22mm plywood panel and mesure weights with throughbolts first then take them out and see at which point the glue (or rather the wood) fails... should be interesting.

Will put video on youtube...

Safe sailing.

 

[al.carpenter]

Just found this on youtube

http://www.youtube.com/watch?v=oYJ5Of3XubI

for info only

 

[john_morris_uk]

Again, I would not advise on gluing a grabrail... you have to think and understand wood and how it works, its mechanical properties...
If you glue wood on wood (even more if it is wood on deroule plywood, which is likely to be the case for your bulkhead) it is guaranteed that even if you have used the best quality bonding agent, if you apply a 80kgs force parallel to the bulkhead on the two, three four or even six times 4cm2 of contacting fibres these will fail (even quarter sawn timber). Your glue will not fail, it is much stronger than cellulose etc... but the wood will. As a shipwright I break up glued wood nearly every day (not often structural... being a traditional boat builder) and sometimes it amazes me how easy it is to split apparently healthy and well structured straight fibres, so more in the case of plywood which is a vulgar "peeling" and has no strong bonding between fibres...
Every single bolt (even 5mm diam) you use will have hundreds of kilos of resistance, shearing or pulling... Some people are giving quite odd advice on here and will not be there to pick you up when you find yourself at the other end of your sailboat with your rail in your hand and a big bump on your head...

I agree and like you I am amazed that people would consider screwing or glueing hand holds.

Through bolt them every time!

Even the ones down below on my boat were through bolted from new by the builder. They have plugs hiding the bolt heads which are countersunk into the handles so they all look very neat.

Even though some people say, "Oh its only down below, it doesn't matter so much" or words to that effect, then I would argue that when you caught out in some sort of rough seas and are hanging on for grim death as you make your way round the boat down below, the loads you put on the grab handles will be much more that 86 Kg of tubby sailor and you will be glad you bolted them!

And lots of sailors weigh a lot more than 86 kg John...

I will be very interested to see the video of the test results.