Mast base corrosion: Repair or shorten?

[chris95040]

Originally Posted by AmericanVagrant

...The rig isn't all that heavy, and I can epoxy it for UV stability.

The compressive loads at the base of the mast far exceed the weight of the mast.

The step for my (300 pound) mast is designed around a 25,000 pound load.

[Reefmagnet]

I'll offer a another opinion. The surprisingly thin stainless steel mast base and anodised Selden spar was the standard arrangement on the Vega - one of the most lauded small sailing boats of the modern era. It's a great boat but does have it's design flaws, particularly the mast support beam. Be that as it may, these flaws - even when repaired to the original specifications - will still remain serviceable for many years.

Long story short; I'd suggest trimming back the corrosion and using heavy PVC tape and Duralac to insulate the base from the mast as best as possible. One mod I'd recommend is to add a couple of small slots with a rat tail file at the bottom of the mast to allow water to drain out. This repair should remain serviceable for quite some time.

On the subject of the mast support beam, those added plates and that 'orrible rusted gland suggest to me there has been or is a problem with the mast support beam, as that stuff has possibly been added in the past more to support the deck then to raise the height of the mast. No surprises there. Now I do know for a fact that a Vega can go a long way with a sagging support beam with little more repair than judiciously applied wood wedges, but it, IMO, will be a better investment of your time and resources to repair issues with the support beam if it has seen better days before getting too carried away reinventing the mast base arrangement.

Just my $0.02!

[reed1v]

I would just leave it alone and stop further corrosion. Its from standing water. You need more drainageways. If you want to make it look nice, clean and epoxy. Or add a simple shoe that runs about half foot up the mast base. In any event, the in line vertical compression strength of aluminum is off the charts so plenty of reserve strength.
There is virtually no lateral compression or movement at the base, and as epoxy has very good compression strength, would simply puddy, clean, paint and be done with it.
A machine shop can also fit the base with an extra layer of aluminum and attach with either rivets or just a simple key lock(not car locks kids), keys like you have on your prop shaft to keep the prop from spinning around the shaft freely. In any even the solution is simple and cheap.

PS, if going with a shoe, locate it inside the mast.

[AmericanVagrant]

Well I completed the repair and have documented the procedure on my website. Feel free to take a look by going here: Sailboat Mast Base Repair | American Vagrant





Thanks for everyone's advice!

[Sailmonkey]

Perfect!!

[Hudson Force]

'looks great!

[Alastair A]

Looks good to me. Thanks so much for your update info. Good choices with your strategy and crafting of materials. Best wishes for your future sailing exploits. Cheers. A.

[Alastair A]

PS. I am trusting that the boards with laminate are not cabinetry recycled "chip board"? Please assure me that your packers are marine grade maretial? Please? A.

[Alastair A]

It seems that AV locks me out of encouraging his website. It may be because I mentioned laminated chip-board. If it has happened, then this is not a good way to recycle kitchen cabinetry. So sadly, if I am mistaken. A.

[GordMay]

Originally Posted by Alastair A

... Please assure me that your packers are marine grade maretial? Please? A.

...I made a spacer by encapsulating G10 in fiberglass. I gave it a large footprint to insure a widely distributed load...
... I cut the flanges off the foot, which caused the corrosion in the first place. Instead I created a plug with fiberglass sheets I had leftover from cutting out portholes...

➥ Sailboat Mast Base Repair | American Vagrant

[DeepFrz]

Is that aluminum sitting on top of stainless steel? You need a barrier between them.

[AmericanVagrant]

Thanks guys!

Originally Posted by Alastair A

PS. I am trusting that the boards with laminate are not cabinetry recycled "chip board"? Please assure me that your packers are marine grade maretial? Please? A.

Originally Posted by Alastair A

It seems that AV locks me out of encouraging his website. It may be because I mentioned laminated chip-board. If it has happened, then this is not a good way to recycle kitchen cabinetry. So sadly, if I am mistaken. A.

Hello A., as Gord noted the packers are actually of fiberglass sheets and not chip board. On my website, all comments must first get moderated (to avoid spam). It's online now, I really appreciate your offer! I'll be in touch as I get nearer to Oz.

Originally Posted by DeepFrz

Is that aluminum sitting on top of stainless steel? You need a barrier between them.

It is - I used a thin coat of epoxy to isolate them.

[Alastair A]

Hello all at CF. Please look to the past pic's provided.
I am glad if this vessel is sea-worthy. Any questionable trouble hiding inside the mast is most difficult. Please pardon me, not my boat. But this is my sailing community. Please advise your selection of internal and cut to profile packing boards?
I an nicely intended with all CF, but sailing integrity comes first.
A.

[Alastair A]

Hello J. You are most welcome in Sydney. I know this end of the Pacific. If you put chipboard into a mast base the I suggest you acknowledge with honor or correct me with facts and actual.
If not, then your early reputation will be world wide announced, before you even set voyage. Not my voyage situation. Please don't leave a maintenance death trap as you choose another vessel.
Doubtfully, A.

[DeepFrz]

AV, there are two problems with using a thin layer of epoxy to isolate the mast and the stainless plate. One is that epoxy that is not reinforced can easily chip. The 2nd is that unless the epoxy is painted it will deteriorate from UV exposure. Both of these situations may leave you with the exact same problem that you have been attempting to fix.

Good luck.