Mast mast compression post base question

[ivisonm]

HI all,

I have had to dig out all the concrete and rusty ballast that is sitting under the main mast compression post as the concrete was filled with shims that have gone rusty because of the previous owners lack of care. The rest of the ballast is lead but there is a 5" gap between the lead and the base of the compression post. I was going to get some lead to make the area under the compression post even but I'm not too sure if I can do this.as the lead under the post is very uneven.

Is there an 'proper' way of packing the area under the compression post? I was thinking of concrete on top of the lead with a thick peice of teak (2" solid) sitting on top of that for the post to sit on and then glass the lot in.

Boat is Bowman 46 circa 1982.

Thanks,
Mark

 

[PetiteFleur]

Either use a solid piece of Teak(or laminated pieces), or similar hard wood or make a support of stainless tubing with plates top & bottom. Size to suit the dimensions of the compression post. If you can't get a suitable large piece of tubing then you could use several smaller pieces with a thicker plate top & bottom. Sit the base on a stiff epoxy base to take up any irregularities. All done without the mast in place of course.

 

[Deleted member 36384]

You can build up very strong posts with marine ply and epoxy. To avoid the base of the mast or whatever digging in to the ply I would epoxy bond on top of the compression post a flat, say 1/8" thick stainless plate.

The ply wood post can be bonded onto the lead or what ever the irregular base is using an Epoxy mix.

Type West System in google and go to the Gudgeon Brothers West System Home page. They have lots of tips for using Epoxy is structural bonding conditions.

 

[npf1]

I think the mast on mine is stepped on either lignum vitae or heartwood - seems to have lasted well.

 

[Mrnotming]

compression post

Hi all.
Make sure that the end of the tube bearing on the pad you make up is closed off with a metal plate or end piece. We wondered why the rigging went slack: reason, the post (s/s tube had dug into the support timber as it was open ended!good suggestions all round!

 

[jason -and the arguenauts]

What about the ballast element ie the steel scrap? I'd be surprised if Bowman had done such a bodge as to use concrete and metal to top up the ballast. Sounds more like an owner mod to rectify a tenderness problem. Either way you need to add some ballast to replace what you take out.

I'd be inclined to use a lead spacer with a steel plate for the base of the mast support and epoxy inbetween it and the old lead to take up any gaps. A few screws through and into the old lead just to make sure there is no lateral movement.

 

[ivisonm]

Re: Mast compression post

I plan on adding extra lead ballast to replace the rubbish I took out and I have some nice thick pieces of solid teak and stainless plate to make a really strong base that can sit on top of some additional lead ballast held with epoxy.

The end of the compression post is flanged so there will be no problems with digging into the teak base.

Some very useful information on the west website about bonding..

Thanks for all the suggestions guys.

 

[oldsaltoz]

I plan on adding extra lead ballast to replace the rubbish I took out and I have some nice thick pieces of solid teak and stainless plate to make a really strong base that can sit on top of some additional lead ballast held with epoxy.

Thanks for all the suggestions guys.

I would avoid the use of timber in this application at all costs, bilges are exposed to oil, water, cleaning chemicals and god knows what, subject to rot both wet and dry, crushes, spreads, cracks or splits under load.

I don't even use it for backing pads, stainless steel is far more reliable.

Avagoodweekend......

 

[ivisonm]

Re: Mast compression post

What a stoke of luck! A colleage is replacing an old roof and has loads of lead that he was going to scrap so I may be able to make a complete lead base for the compression post.