Bottom Job

[Terry B 73]

Hi all, got the dreaded pox on my 29 foot keeler and need the bottom re-done. I'm in Akl.

Was told Brin Wilson in Gulf Harbour was good - any other options?

Gonna be expensive so I should get a cuppla quotes.............

 

Ta.

 

 

[MarkMT 68]

No personal experience or recommendations, but some other possibilities that might be worth investigating...

 

http://www.osmosis.co.nz

http://www.osmosisinboats.co.nz

[El Toro 110]

Above and Below Marine just smashed out a bit from my plastic turd

[wheels 544]

Just open the blisters, let them dry out and fill with epoxy filler, Epoxy undercoat and your away laughing. Don't get sucked into the expensive plane back and reglass buisness.

Osmosis was a thing waaay back 70's/early80's with a genuine polyester resin. For later in the 80's, the Vynil Ester rester became available and stopped that problem. So depending on the hulls age, it could be osmosis, of just the odd void that sucked in water, due to a poor layup. Either way, same remedy sorts it out.

[Terry B 73]

Hi Wheels, I've just had the bottom professionally anti fouled and I know that I've had blisters before and with each anti foul there's more.

The anti foul guys reckon it's riddled with them - if they did what you say (and what they've done in the past) and 

let them dry out and fill with epoxy filler, Epoxy undercoat and your away laughing they say they'd basically be doing half the bottom anyway!

 

First quote is in at a breath taking $21K including 5 weeks hardstand..........gosh, my wife will be pleased  

 

Supplementary question Mr Speaker - if I do nothing, ignore the problem and sail on regardless - do I eventually sink? seriously, I have no idea what it means to have osmosis.

 

[Terry B 73]

Just read this which I thought was interesting...............if your attention span is that of a 20 year old, it might be a bit long..........

 

https://www.yachtsurvey.com/BuyingBlisterBoat.htm

 

Any comments?

 

 

And going back to the cost of a full bottom job, the boats probably worth $30-35K as it's in good nick (apart from the obvious!).

Bottom job probably ain't worth it. Just sail on regardless.........

[Fish 0]

Guys at the club have done what Wheels said. Worked fine.

Of course its better to do it before you put fresh AF on, but I'm guessing your not in the mood for comments like that.

It also helps if you can haul out at a club / somewhere that doesn't charge moonbeams per day just for hard stand (like any commercial hard stand). Example being Weiti.

 

I think the annoying bit in the process is letting things dry once you've popped all the blisters.. Like good cheese, it takes time. Hence needing a hardstand that charges by the week and not by the day. Nothing more complicated than a paint scrapper to pop the blisters / scrap back, and a putty knife to fill with epoxy. plus a repaint of the hull, interprotect, AF etc.

 

There is nothing techo about it in regards to DIY (certainly not $20k techo) and just a little bit of manual labour if you do it yourself. I hope your back is feeling better buy the way.

 

PS, I've not done this myself, I've got a wooden boat

[Frank 157]

There is a gentleman in our club who has done what wheels said , the boat was a 70's vintage Spencer design. It was semi abandoned and had not been hauled for many years.

 

The blistering was extensive and the blisters large he ground them out then waited until they stopped weeping. That took a long time I can't recollect exactly but is was many months, maybe a year. Then they were filled with pure epoxy glue (West System) and from there the usual paint process etc.it seems to have been successful with no new blisters in the intervening 4 yrs and he was adamant he had done many boats this way. I should say he is a boat painter and this was an extreme case I'm sure yours wont be anything like that bad. Glue is best as the filler because  it is the least porous .

[Priscilla II 414]

Just open the blisters, let them dry out and fill with epoxy filler, Epoxy undercoat and your away laughing. Don't get sucked into the expensive plane back and reglass buisness.

Osmosis was a thing waaay back 70's/early80's with a genuine polyester resin. For later in the 80's, the Vynil Ester rester became available and stopped that problem. So depending on the hulls age, it could be osmosis, of just the odd void that sucked in water, due to a poor layup. Either way, same remedy sorts it out.

Vinylester also gets the pox too.

Your advice to TB is most prudent given 2 points.

Very rare for a GRP boat to die from the pox.

29ft yacht ain’t never going to ever recover the cost of a full professional osmosis repair.

https://mike-menzies-marine.co.nz/osmosis-blistering/

[Rangi1 51]

I had the bottom of my 40 footer done a couple of years ago by Barry Cawson. Highly recommended and much cheaper than Brin Wilson.

[Terry B 73]

Thanks all. I'll ponder.

 

I'm not interested in doing anything major myself - can't be bothered at my age. I'm happy doing little projects and keeping the boat varnished etc - but a dirty job like this ain't for me.

[wheels 544]

It wasn't all that many years ago that blisters were considered to be the Ebola of Boat sicknesses. Businesses were created and boat owners parted with mega amounts of hard earned cash. There were horrendous stories that the Hulls were dissolving away and major work would have to be carried out urgently or the Boat would be damaged beyond repair. There were special machines that planned the gelcoat away and then various layers of GRP. There were many methods of drying from hardstanding for a year, storage in a dry heated shed, to plastic wrapping with a layer of wind break material between the plastic and Hull and then a vacuum line connected and suction pump sucking away for weeks on end. There was even a blasting process using dry ice which was supposed to blow open the blisters.
While all this was happening, a fellow at Epiglass was carrying out R&D on the issue and came up with the simple remedy of which I have given above. He also stated that Osmosis was not as bad as the horror stories suggested. Nor was the repair time necessary. It was a simple case of break open the blister, give it a good wash with fresh water and dry. If any were still weeping, grind into them a bit more. Then fill. No need to hard stand for weeks or months on end.
 

[Fish 0]

Thanks all. I'll ponder.

 

I'm not interested in doing anything major myself - can't be bothered at my age. I'm happy doing little projects and keeping the boat varnished etc - but a dirty job like this ain't for me.

Given that, when you are looking for prices, bear in mind the hardstand costs. Brin Wilson are at Gulf Harbour, and while they are good at what they do, the hardstand costs are moon beams. Smithy recently made a comment about being robbed for mast storage there. GH have a high day rate. All the work there is based around getting the boat in and out asap, which doesn't work with an osmosis job.

 

It may be worth trucking the boat to a boat builder who is not at a marina. I understand your boat isn't too big? If a boat builder has his own land, then the economics will be substantially different. Your paying more for the labour and not for the hardstand, as such.

 

And the patch job is fine for DIY, but a professional will not want come back if he misses a spot, so it may be up to you to ask for a patch job (i.e. what wheels says), and not a full bottom job, on the proviso you carry the risk if a bit is missed.

[Fish 0]

A variation on the concept of trucking your boat somewhere (and to avoid dropping the mast), is going to a more out of the way boatyard up one of the rivers locally. Examples being Fusion Marine at Silverdale, up the Weiti River, or Robertsons at Warkworth. I think there are some others around but I aren't familiar with them. There is still boat related work going on at Stevensons yard (the old cement works) up Weiti, but I'm not sure if its commercial or not. All easily accessible at high tide, and worth the effort to save on a $21k quote.

 

Because the cost of land is less at these places, I'd expect a better overall price for the work when compared to a boat builder based at a prime marina location, like Brin Wilson.

[chariot 244]

I have done what Wheels said on one of my previous boats. Ground out the blisters, washed thoroughly with fresh water and left to dry for a few weeks. Sealed with West System then filled with West system and micro ballons mixed together then just a bit of filler to get a fair finish. Epoxy undercoat applied to spots as spot primer then antifoul. 

That was a Raven 26 and they were fairly pox prone. Had that boat for13 years and never had another problem. Did that on second year of ownership.

[philstar 62]

We had a Lotus 10.6 Rewi which was done at Hobsonville marina a few years ago. It cost around 15k from memory.

Full plane back, dry out, a layer of glass and epoxy, then anitfoul.

The performance difference afterwards was huge I think she lost alot of weight. 

 

As far as I see if you like your boat and intend keeping her its probably worth doing. 

[harrytom 682]

have you popped a blister or 2  and does it have a vinegar smell?? I had  30 on the cav and luckily there was a builder working on another yacht,he had a look and popped a few,ground one back and he ,all good it just on the gel coat,fill with expoxy  prime and away you go.

[wheels 544]

In regards to the glue comment above somewhere, I would use the filler for below waterline use. It won't absorb water and is much easier to sand that Glue is.