Buying a boat with Osmosis, Y/N ???

[Brabs70]

Hello everyone,

I am looking for some advice on a westerly Corsair, in-mast furling, so i have been offered the corsair for 26k after some negotiation, this is the specs, All taxes paid. UK Reg. In mast main.(fair) 2xGenoa(good) almost new Yankee. New electronics 2024. B&G. Ais. Hydrovane. Ram auto pilot. Electric Lewmar winches in cockpit x2. 4 more winches in cockpit. New dect tread 2025. New fridge 2024. Freezer. New bateries 2024, 1x start and 3 house 330ah. 650W solar +2x30A MPPT's. 2x heads. Front and aft cabin. Electric winlas. BBQ. water maker, new tv. 3000W inverter. 1000W generator. Vectron charger.

So my issue is, she has a few blisters size... 10-15mm.(and smaller) Wide spread mainly aft, as you can see she is kitted out for offshore cruising, but the question is, do i buy or not, please give me your honest opinions, if i buy obviously a full survey will take place, i have added some pictures,

 

[Minerva]

That’s a lot of boat for the money! I’d be snapping their hand off

 

[fredrussell]

…So my issue is, she has a few blisters…

Do your research online re osmosis treatment. ‘Refit and sail’ on YouTube has a good explanation of treatment and a full series on him treating an ‘osmosified’ boat of a similar size and age to this westerly.

 

[Brabs70]

Do your research online re osmosis treatment. ‘Refit and sail’ on YouTube has a good explanation of treatment and a full series on him treating an ‘osmosified’ boat of a similar size and age to this westerly.

Will take a look

 

[Tranona]

Presumably that is not in the UK. If it is in the EU then it may be EU VAT paid status depending on where it was on 31/12/2020. If it is outside either territories then the "all taxes paid" is meaningless. Probably one of the reasons it is not much more than half the price of a similar boat in similar condition in the UK is because it cannot be brought into either territory without importing it and paying VAT. Whether you buy it depends on your plans. If you intend ocean cruising and not bringing it to Europe then it may be a good buy. Registration is irrelevant. If you have more on the provenance - its past history of changes in ownership and where it has been you might be able to work out where you can use it.

Osmosis blisters are common on these boats and not a reason for rejecting it. Plenty of material available as already suggested to help you understand how to deal with it and keep sailing.

 

[Brabs70]

Presumably that is not in the UK. If it is in the EU then it may be EU VAT paid status depending on where it was on 31/12/2020. If it is outside either territories then the "all taxes paid" is meaningless. Probably one of the reasons it is not much more than half the price of a similar boat in similar condition in the UK is because it cannot be brought into either territory without importing it and paying VAT. Whether you buy it depends on your plans. If you intend ocean cruising and not bringing it to Europe then it may be a good buy. Registration is irrelevant. If you have more on the provenance - its past history of changes in ownership and where it has been you might be able to work out where you can use it.

Osmosis blisters are common on these boats and not a reason for rejecting it. Plenty of material available as already suggested to help you understand how to deal with it and keep sailing.

Hi Tranona

Thank you for your reply,
My intention would be to bring it to the Caribbean in the near future — the plan is to use it for offshore cruising, so VAT status isn’t a deciding factor at this stage.

I agree on the pricing point as well — being outside those markets clearly affects value, which is part of the appeal from my side.

I’m currently trying to build up a clearer picture of the boat’s provenance and ownership history, just to understand where it’s been over time.

Also agree on the osmosis — from what I’ve seen and read, it seems fairly typical for boats of this age and something to manage rather than a reason to walk away.

Appreciate your input.

 

[Concerto]

The price for the boat is very keen for one of these. The condition of the interior woodwork is showing signs of lots of wear. This is not expensive to solve. Westerly used a 2 pack lacquer, not varnish. On my Fulmar I stripped my woodwork back to bare wood and recoated with 3 coat of the original lacquer. I made a PowerPoint presentation on how I started this. I should mention I changed the stripping from a cabinet scrapper to 1½" chisel sharpened on a small diamond grinder and using the burr. The lacquer is quite soft and easy to remove. I did the whole boat in stages of stripping and immediately refinishing immediately. You would need 10 litres and this should cost about £140 including 5 litres of thinners.

https://wiki.westerly-owners.co.uk/images/2/25/Interior_Woodwork_Concerto_PowerPoint.pdf

 

[Brabs70]

The price for the boat is very keen for one of these. The condition of the interior woodwork is showing signs of lots of wear. This is not expensive to solve. Westerly used a 2 pack lacquer, not varnish. On my Fulmar I stripped my woodwork back to bare wood and recoated with 3 coat of the original lacquer. I made a PowerPoint presentation on how I started this. I should mention I changed the stripping from a cabinet scrapper to 1½" chisel sharpened on a small diamond grinder and using the burr. The lacquer is quite soft and easy to remove. I did the whole boat in stages of stripping and immediately refinishing immediately. You would need 10 litres and this should cost about £140 including 5 litres of thinners.

https://wiki.westerly-owners.co.uk/images/2/25/Interior_Woodwork_Concerto_PowerPoint.pdf

Hi Concerto,

Thank you for your reply, very good presentation you have put together, if i decide to buy, i will tackle the interior, my main concern is buying the boat with Osmosis, if i do buy her, it will be a long term thing, so not really concerned about the re-sale value

 

[Fr J Hackett]

The only thing that would concern me is what make is the in mast reefing system, is it an original or add on if the latter I would be dubious.

 

[Brabs70]

The only thing that would concern me is what make is the in mast reefing system, is it an original or add on if the latter I would be dubious.

I will put the question to the owner

 

[garymalmgren]

So my issue is, she has a few blisters size... 10-15mm.(and smaller) Wide spread mainly aft,

How do you know this?
Have you personally inspected or is that a report from a surveyor or the owner?
Have you popped the blisters yourself or seem photos of them popped?
How many is , "a few"?
remember that the seller it trying to actually sell the boat.

My opinion.
Blisters can mean osmosis ( a deterioration of the FRP that allows water to enter the matrix) or it can be a lifting of the gel coat or anti fouling, so identifying what the blisters are would be my first step.
Either way, it would not worry me that much. No boat as sunk from osmosis, however (I just checked AI with the search "osmosis in a westerly corsair") it is not uncommon for older Westerlies to have the hulls stripped and treated. You could get a quote on that if it bothers you that much.

As for boat and gear. The list of what is fitted is very impressive and would show that the previous owner was serious about the quality of what was fitted.
I say, Go, now!

Gary

 

[Stemar]

The best treatment for "osmosis" is a dubious sucking of teeth, "What a shame about the osmosis. A proper treatment is very expensive, so I'm afraid I'll have to reduce my offer by (silly amount)" Then negotiate on the silly offer.

Once you've got the boat, go sailing, and deal with the blisters when you come out for a winter - if you can be bothered.

 

[Brabs70]

So my issue is, she has a few blisters size... 10-15mm.(and smaller) Wide spread mainly aft,

How do you know this?
Have you personally inspected or is that a report from a surveyor or the owner?
Have you popped the blisters yourself or seem photos of them popped?
How many is , "a few"?
remember that the seller it trying to actually sell the boat.

My opinion.
Blisters can mean osmosis ( a deterioration of the FRP that allows water to enter the matrix) or it can be a lifting of the gel coat or anti fouling, so identifying what the blisters are would be my first step.
Either way, it would not worry me that much. No boat as sunk from osmosis, however (I just checked AI with the search "osmosis in a westerly corsair") it is not uncommon for older Westerlies to have the hulls stripped and treated. You could get a quote on that if it bothers you that much.

As for boat and gear. The list of what is fitted is very impressive and would show that the previous owner was serious about the quality of what was fitted.
I say, Go, now!

Gary

Hi Gary,

Many thanks for your reply, i received a couple of pictures from the owner, he said its widespread mainly aft, i have a surveyor going to look at the Hull on Monday, so hopefully will have all my answers, the Owner has been really upfront and honest, and i believe the price and the ability to just walk away should the readings be through the roof, why not consider this a lot of boat for the price

 

[Tamar]

There was an old saying....No boat ever sank of osmosis. I don't know how true that is but I see most plastic boats in the yard with blisters underneath. My own boat came with added blisters, I think if you burst them and they smell of vinegar it's not good. But don't let that put you off, just clean out, dry out and fill them.

 

[steve yates]

I looked at a beautiful westerly Conway last week that has been rebuilt by a bowmans boat builder as a labour of love, well over 100k spent on it. Brand new teak decks, stunning joinery work, watermaker, never used hydrovame, inner forestay added, ew engine, new standing rigging etc. All the upgrades you could ever wish for basically. It has mild osmosis, which didn’t really bother me too much.
I thoughtI had found my forever boat on paper, tough, seaworthy, two sleeping cabins, But when I went aboard her, there was no excitement, no feel! The thought of spending months aboard her was just not appealing, it was really dissapointing. Iso wanted to love that boat, but I just didn’t. I already have an old westerly ketch ( longbow) and I prefer being in her! I then looked at a typhoon and a sweden yacht 36, wow! Night and day, I loved the sweden 36, now thats a boat I could live on for very long periods.

Anyway, I digress, sorry. Point is I got a quote for the osmosis treatment from hayling yacht company who are reputed to be experts on this, so this might be useful for you as the boats are very similar size…

Winter Prices 2026/27 (Valid for 60 days)

Standard Treatment – “Water to Water” including 5-year Guarantee £9,150.00

Superior Treatment – “Water to Water” including 400g sheathing with 5-year Guarantee £11,250.00

Superior Treatment – “Water to Water” including 400g sheathing without 5-year Guarantee £10,405.00

Guarantee Value (if included above) £10,000.00



Summer Prices 2026 (Valid for 60 days)

Standard Treatment – “Water to Water” including 5-year Guarantee £8,465.00

Superior Treatment – “Water to Water” including 400g sheathing with 5-year Guarantee £10,410.00

Superior Treatment – “Water to Water” including 400g sheathing without 5-year Guarantee £9,645.00

Guarantee Value (if included above) £9,000.00

All prices are exclusive of VAT.

 

[Tranona]

The only thing that would concern me is what make is the in mast reefing system, is it an original or add on if the latter I would be dubious.

Looks the original in the photo. The boat has been places in the last 40 years so assuming the mechanism has been maintained properly (not difficult) and the sail is in good nick, nothing to worry about.

 

[Brabs70]

I looked at a beautiful westerly Conway last week that has been rebuilt by a bowmans boat builder as a labour of love, well over 100k spent on it. Brand new teak decks, stunning joinery work, watermaker, never used hydrovame, inner forestay added, ew engine, new standing rigging etc. All the upgrades you could ever wish for basically. It has mild osmosis, which didn’t really bother me too much.
I thoughtI had found my forever boat on paper, tough, seaworthy, two sleeping cabins, But when I went aboard her, there was no excitement, no feel! The thought of spending months aboard her was just not appealing, it was really dissapointing. Iso wanted to love that boat, but I just didn’t. I already have an old westerly ketch ( longbow) and I prefer being in her! I then looked at a typhoon and a sweden yacht 36, wow! Night and day, I loved the sweden 36, now thats a boat I could live on for very long periods.

Anyway, I digress, sorry. Point is I got a quote for the osmosis treatment from hayling yacht company who are reputed to be experts on this, so this might be useful for you as the boats are very similar size…

Winter Prices 2026/27 (Valid for 60 days)

Standard Treatment – “Water to Water” including 5-year Guarantee £9,150.00

Superior Treatment – “Water to Water” including 400g sheathing with 5-year Guarantee £11,250.00

Superior Treatment – “Water to Water” including 400g sheathing without 5-year Guarantee £10,405.00

Guarantee Value (if included above) £10,000.00



Summer Prices 2026 (Valid for 60 days)

Standard Treatment – “Water to Water” including 5-year Guarantee £8,465.00

Superior Treatment – “Water to Water” including 400g sheathing with 5-year Guarantee £10,410.00

Superior Treatment – “Water to Water” including 400g sheathing without 5-year Guarantee £9,645.00

Guarantee Value (if included above) £9,000.00

All prices are exclusive of VAT.

Hi Steve

Thank you for sharing all the information, this is something to consider, should i go ahead with the sale, as mentioned, i will wait on the verdict from the Surveyor, i really like the boat, she is well kitted out, and i currently have a westerly 33 that i am selling, and to be honest, i did have second thoughts, but to add all this equipment to mine, plus replace the standard rigging, and fully upgrade, i would probably talking thousands, so hence i am selling mine, and now looking at this Corsair