Re-bedding pushpit

[TimfromMersea]

On my Beneteau Oceanis 281 the split backstays are fixed to tangs welded to the pushpit.

inevitably over 21 years of the boat’s life the pull of the rig has broken the seal around the pushpit legs and they are leaking.

Could I please ask some advice on what sort of sealant to use to re-bed the legs? They are bolted through the deck with a threaded leg and nuts and washers on the bottom.

 

[mrangry]

I would use butyl on bolted deck fittings

 

[Keith 66]

^^^^ Butyl best option, If you use Sikaflex you wont get the fitting off again without severe risk of tearing the gelcoat off.

 

[dansaskip]

There are two types of Sikaflex, one is the adhesive type that Keith 66 warms about, the other is just a sealant., not an adhesive so you can use that without long term problems. The trick is to make sure that the holes have a slight countersink so that the sikaflex can form a sort of o-ring seal and then bolt down - but this is the important bit not all the way as you will squeeze out all the sealant - give it some time for it to set a little, Maybe 24 hts temp dependent, then finish bolting down firmly.

 

[vyv_cox]

^^^^ Butyl best option, If you use Sikaflex you wont get the fitting off again without severe risk of tearing the gelcoat off.

That is just not true. I only use Sikaflex or Puraflex for every sealing job aboard as I do not have stowage for a wide range of sealants. Over the past 30 years I have removed or replaced dozens of fittings, including light window frames. Never damaged a fitting or gel coat.

 

[rogerthebodger]

On my Beneteau Oceanis 281 the split backstays are fixed to tangs welded to the pushpit.

inevitably over 21 years of the boat’s life the pull of the rig has broken the seal around the pushpit legs and they are leaking.

Could I please ask some advice on what sort of sealant to use to re-bed the legs? They are bolted through the deck with a threaded leg and nuts and washers on the bottom.

IMHO Rigging tangs attached to a pushpit is very wrong as you found it puts too much load on the pushpit

I would fit proper chainplates with backing plated to the hull / deck.

A pushpit , pulpit and stanchions can get damaged so needs to be able to be removed for repair.

On a GRP boat I would fit a base to the deck sealed with sikaflex or the like. This base has tapped holes so the base of the pushpit bolts on to the deck plate to make the pushpit easy to remove

 

[Snowgoose-1]

I would use butyl on bolted deck fittings

That is just not true. I only use Sikaflex or Puraflex for every sealing job aboard as I do not have stowage for a wide range of sealants. Over the past 30 years I have removed or replaced dozens of fittings, including light window frames. Never damaged a fitting or gel coat.

I purchased a hatch and it came with Butyl sealant. Probably me but I made a real mess with it and and reverted CT1. The instructions mentioned to keep nipping up the screws over a large number of days which also put me off.

However, I know of a major boat builder uses Butyl on fittings . Mainly due to new owners changing their minds on add ons. Many forumites use it with success and perhaps I should try harder.

 

[Tranona]

IMHO Rigging tangs attached to a pushpit is very wrong as you found it puts too much load on the pushpit

I would fit proper chainplates with backing plated to the hull / deck.

A pushpit , pulpit and stanchions can get damaged so needs to be able to be removed for repair.

On a GRP boat I would fit a base to the deck sealed with sikaflex or the like. This base has tapped holes so the base of the pushpit bolts on to the deck plate to make the pushpit easy to remove

Well the boat has been around for 21 years and the mast has not come down - and over 300 of this model boat have been in use since the mid 1990s so not sure why a request for advice on sealant leads to a claim that a redesign is needed. Both the builder and designer (Group Finot) know a thing or two about building boats.

 

[rogerthebodger]

Well the boat has been around for 21 years and the mast has not come down - and over 300 of this model boat have been in use since the mid 1990s so not sure why a request for advice on sealant leads to a claim that a redesign is needed. Both the builder and designer (Group Finot) know a thing or two about building boats.

This is my opinion as being a mechanical designer for many years it just my personal view.

I have also built my own boat and I have split back stay and would not attach my back stays to my pushpit.

Not a designer working for a manufacturer does have a very different considerations to a private individual designing and building a boat for his own use

Just because a profissional (paid for building equipment (boats) will design the strength for that they consider "normal" use. To make a piece of equipment "too strong" is not cost effective. This is very different to a knowledgeable self builder building for himself.

If anyone does not wish to take my recommendations that is their choice

 

[mrangry]

I purchased a hatch and it came with Butyl sealant. Probably me but I made a real mess with it and and reverted CT1. The instructions mentioned to keep nipping up the screws over a large number of days which also put me off.

However, I know of a major boat builder uses Butyl on fittings . Mainly due to new owners changing their minds on add ons. Many forumites use it with success and perhaps I should try harder.

The beauty of using butyl tape is that it isnt messy. It is a sealant rather than an adhesive and requires mechanical fixings to maintain that seal. It can also be dis assembled with ease whereby using a sealant/adhesive will require removal/cleaning before re sealing. Both however will seal well its just down to preference I suppose.

 

[Tranona]

This is my opinion as being a mechanical designer for many years it just my personal view.

I have also built my own boat and I have split back stay and would not attach my back stays to my pushpit.

Not a designer working for a manufacturer does have a very different considerations to a private individual designing and building a boat for his own use

Just because a profissional (paid for building equipment (boats) will design the strength for that they consider "normal" use. To make a piece of equipment "too strong" is not cost effective. This is very different to a knowledgeable self builder building for himself.

If anyone does not wish to take my recommendations that is their choice

I think most of the regulars know all this - but none of it is perhaps relevant to somebody who simply asks what sort of sealant he should use to rebed the original fittings.

So if you want to answer the question and help the OP what sort of sealant would you use?

 

[rogerthebodger]

I think most of the regulars know all this - but none of it is perhaps relevant to somebody who simply asks what sort of sealant he should use to rebed the original fittings.

So if you want to answer the question and help the OP what sort of sealant would you use?

I would use what I always used to seal and through fittings is sikaflex.

But I do try to avoid any through deck holes to reduce the possibility of future leaks and allow deck fittings to be removed for repair without the need to remove inside paneling

You may be able to see how I did it on my boat

https://flic.kr/p/WVi6c5

This shows how my deck winch ,pushpit, fairlead and turning blocks are fitted.

My backstay chain plates cannot be seen as they are behind the cockpit raised sides

 

[Tranona]

I would use what I always used to seal and through fittings is sikaflex.

But I do try to avoid any through deck holes to reduce the possibility of future leaks and allow deck fittings to be removed for repair without the need to remove inside paneling

You may be able to see how I did it on my boat

https://flic.kr/p/WVi6c5

This shows how my deck winch ,pushpit, fairlead and turning blocks are fitted.

My backstay chain plates cannot be seen as they are behind the cockpit raised sides

Can't imagine anything more different from the OP's boat - but at least a sealant recommendation, although it has already been mentioned.

 

[rogerthebodger]

Can't imagine anything more different from the OP's boat - but at least a sealant recommendation, although it has already been mentioned.

With a GRP boat I would bolt a fixed pad to the GRP deck sealed with Sikaflex and tapped holes in the pad so the fittings would bolt to the fixed pad

I did this on a ferrocement boat I owned and no leaks through the deck fittings and if any fittings got damaged the fitting ws easy to remove.

Its called design for ease of maintenance but it does cost more which is less of a consideration of the commensal manufactures

as it costs more most manufactures look at the low cost option

I am sure you would consider follow up ease of maintenance on th boats you have rebuilt

 

[Keith 66]

That is just not true. I only use Sikaflex or Puraflex for every sealing job aboard as I do not have stowage for a wide range of sealants. Over the past 30 years I have removed or replaced dozens of fittings, including light window frames. Never damaged a fitting or gel coat.

Sorry but I have a boatbuilder since 1980, I have used & tried just about all the commonly used sealants, Sikaflex is great stuff but can be an absolute pig to dissasemble. I have seen more than a few cases including on my own boat where gelcoat damage ensued because a fitting was effectively glued down, Polysulphide is similar.
If you use it to put ally framed windows in You are lkely to wreck them if you ever have to take them out.
Butyl is always easy to disassemble though my experience is that its UV resistance isnt that wonderful.
Back in the day production builders nearly always used silicone rubber because of easy clean up, just bolt it on leave the squeeze out & cut the excess off once cured.

 

[Tranona]

With a GRP boat I would bolt a fixed pad to the GRP deck sealed with Sikaflex and tapped holes in the pad so the fittings would bolt to the fixed pad

I did this on a ferrocement boat I owned and no leaks through the deck fittings and if any fittings got damaged the fitting ws easy to remove.

Its called design for ease of maintenance but it does cost more which is less of a consideration of the commensal manufactures

as it costs more most manufactures look at the low cost option

I am sure you would consider follow up ease of maintenance on th boats you have rebuilt

There are all sorts of different things you can do - but that does not help the OP who simply wants to know what sealant to use. Suggest you look at boat and see why any other suggestions you make are simply not relevant.

 

[doug748]

This stuff works well a sort of sticky butyl:

Arbomast BR - One Part Butyl Based Sealant

Messy, but keeps well in the tube so you can still use it years later.

.

 

[rogerthebodger]

Is this the boat and backstay attachment

Buying a boat - Schepenkring - The most active yacht broker in the Netherlands

It looks to be as a simple cost cutting design. Its very typical if a ether value engineering excise of a comprise tohave a split backstay to allow easy access to the stern

Am I not allowed to disagree with manufactures design If I consider there is a better way.IMHO

We all have different ways of doing things and so what it you disagree I am only giving my view to the OP and its upto the OP to decide the relevance.''What is the real motives

Isn't it the function of a Forum to have different options and for the members to individual decide what they they wish to do with the info

There has been many threads that give a different advice to what was asked.

In the antifoul thread you proposed coppercoat.= great f the OP was keeping the boat but he said he was planning to sell the boat. We all can be criticised an we should just accept that it you cannot its your problem not mine and don't try to make it so

 

[vyv_cox]

Sorry but I have a boatbuilder since 1980, I have used & tried just about all the commonly used sealants, Sikaflex is great stuff but can be an absolute pig to dissasemble. I have seen more than a few cases including on my own boat where gelcoat damage ensued because a fitting was effectively glued down, Polysulphide is similar.
If you use it to put ally framed windows in You are lkely to wreck them if you ever have to take them out.
Butyl is always easy to disassemble though my experience is that its UV resistance isnt that wonderful.
Back in the day production builders nearly always used silicone rubber because of easy clean up, just bolt it on leave the squeeze out & cut the excess off once cured.

I have removed aluminium framed windows sealed with Sikaflex several times. It's all about using the correct technique. Hammering a chisel between frame and coach roof is guaranteed to cause damage but a thin blade gradually worked around removes anything without damage. A wire might be even better but I have never tried this method.

 

[rogerthebodger]

I have removed aluminium framed windows sealed with Sikaflex several times. It's all about using the correct technique. Hammering a chisel between frame and coach roof is guaranteed to cause damage but a thin blade gradually worked around removes anything without damage. A wire might be even better but I have never tried this method.

I agree I have uses a sharpeed hacksaw blade to cut the Sikaflex.

A cheese wire with the proper wood handles would also do the job

You can also use greaseproof paper to stop the seaflex from sticking then tighten the clamping screws after removing the paper this in effect makes a gasket .

I have also used neoprene foam to seal in the same way