Classical Steel Sloop from 1928

[RodrigoSerraCoelho]

Hello my name is Rodrigo, last year I bought a sailing boat from 1928, with the hull sandblasted and reinforced in 2006.
After the summer season on the water, I'm now preparing to repaint the hull.

My plan is to:

1. Sand (paper 60)
2. Epoxy filler: (Interprime 830)
3. Primer: (Interprime 820)
4. Finishing filler: (Interprime 833)
5. Antifouling.

Find below the link with some pictures of the hull.
Hull detail 1
Hull detail 2

Is this a good painting plan?

Thanks a lot for your help.
All the best,
Rodrigo

 

[Bajansailor]

Welcome to the Forum Rodrigo.
Was she really built in 1928?
Are the plates riveted, or welded?
I am wondering if she was built of iron rather than steel if she is so old?

Re your painting schedule mentioned above, do you have any rusty areas to attend to first?
Re how the hull was 'reinforced' in 2006, do you know if any hull plating was renewed?
How thick is the hull plating - and (most important) - what is the condition of the bilges? Are they rusty or well painted?

 

[RodrigoSerraCoelho]

Hello @Bajansailor, thanks for your message.
The boat is from 1928, it is documented.
The plates are riveted, steel.

I have small rusty areas, that will attend first.
The hull plates were renewed (not all) in 2006.
The original steel thickness has decreased to approximately 2.5 ~ 2.7 mm, which i think its normal for a boat with this age.

There is no rust on the bilge, it was fresh painted last year.

Best,
Rodrigo

 

[srm]

Welcome.

There is a saying that steel boats rust from the inside, and that was my experience.

Your plating is thin, but if shaped to give a rounded hull was probably 3mm to start with (as was my steel boat).

Any rust area need to be cleaned back to bright metal before priming and filling. Needle gun or grit blasting will be better than abrasive paper.
In the bilge and behind fittings there is a danger of rust under the paint if it was not cleaned back to bright metal and correctly primed and painted. The rust detail in your photo is concerning. When cleaning these areas you need to go all round until you get to a good coating over bright metal.

Old steel boats can require almost continuous work to prevent rust spreading unless you grit blast the whole boat, inside and out, to bright metal and use modern coatings. Even then you will probably have rust weeps to treat each year where the coating gets damaged.

 

[RodrigoSerraCoelho]

Hello @srm thanks for your message.
You are right the hull was originally 3mm.
This year I'm already doing a big investment converting from diesel to electric, but next year I would like to sand/grit blast the hull.

I will clean all the rust to bright metal before I start priming and painting.
Like I've mentioned before the boat was fully (inside and outside) blasted back in 2006, and back then they used exactly the same paint schedule I'm planning to use.

Detail of the interior back in 2006.

So with this in mind, is it a good painting plan?

Thanks all again for your messages.

All the best,
Rodrigo

 

[srm]

As it was all blasted and coated inside you should have a nice boat.
Following the same painting plan and materials makes good sense. If you can work in warm dry conditions all the better.

I hope you enjoy your boat.

Sean.

 

[RodrigoSerraCoelho]

Thanks Sean,
Here you have the website for Bries, and all the research i'm doing: SV Bries
Regarding warm and dry weather, well, its the Netherlands, so almost impossible, but i will try my best, and i will share the results.

All the best,
Rodrigo

 

[Bajansailor]

Thank you Rodrigo for the additional information above - your Bries does look very fine, and she has an impressive history!

Just a thought re your proposed painting schedule - you mentioned applying antifouling on to the primer - might it be better to apply a 'top coat' (eg polyurethane) first (on top of the primer) before painting on the antifouling?

 

[srm]

might it be better to apply a 'top coat' (eg polyurethane) first (on top of the primer) before painting on the antifouling?

I missed that and agree that a 'top coat' before antifouling should give a longer life. However, my understanding is that polyurethane is not suitable below the waterline and epoxy will be much better. I had epoxy tar under the antifoul on my steel boat and that lasted for 10 + years other than abrasive damage from groundings on rock in Norway. Interestingly, the steel was bright when lifted out a few months later thanks to the anodes.

 

[Motor_Sailor]

. . . . . but next year I would like to sand/grit blast the hull.

Morning,
Your plan to completely blast the whole of the exterior next year would appear to be a good idea. By what I can see on photo 2, it looks like you have significant corrosion including what could be a hole in the upper top right corner?

Your hull is also very lightly built. Your residual 2.7mm hull plating is equivalent to 12ga American steel which is about the thinnest I have every seen used in a boat and then it was only only 8mtres LOA. Your angle profile framing has also been used (in engineering terms) to no advantage as the flange is against the hull, presumably to allow for riveting and the only longitudinals would appear to be the plate overlaps.

Now none of this is clearly a problem as it's been in existence since 1929! It probably shows how unnecessarily heavy scantling rules for steel boats might be. But I would suggest that you don't have much surplus material to allow to rust away. And the key to preserving steel is surface preparation. You can't have a 'commercial boat' approach of constant chipping and painting and allowable wastage. You must really jump on any rust the moment it appears, even if you plan to do the full job next year.

Hot water (or steam) pressure washing with detergent, is now recognized as the required precursor to grit blasting, as the grit can blast the chlorides into the steel, Then grit blasting is really the only way to go. You're in Holland so all this will be available. The key is to get the timing right! You must have a weather window (or inside covered space) with warm temperatures, where the hull steel is at the same temperature to avoid condensation, with enough time do the blasting and coating in one go. Each coat of Interprime 830 should ideally go on within the overcoating window without sanding, followed by the first coat of antifouling. Don't bother with filler below the waterline - the fish don't care.

Steel is no easier to look after than wood in the long term. It's a different skill set being a steel boat craftsman, but none the less precise. Bodging work will have no less a detrimental impact on the life of your lovely boat, than if it was a wooden classic.

 

[Wansworth]

Your in a very good country for steel and iron boats,they have a rough idea how to do it?

 

[RodrigoSerraCoelho]

Hello @Motor_Sailor , thanks a lot for all the precious information. I'm learning a lot about steel thanks to all.
With all the help provided, i will keep the painting schedule, but I was able to find a boat yard specialised in historic steel boats really close to Bries, and they will pay a visit next week to also give their input.

I will keep you posted, and thanks again for your interest and help.
Best,
Rodrigo