Question regarding GRP covered wooden hull.

[Flying Fox]

Hi All,

I'm new here and new to restoration so please excuse any seemingly ignorant questions.

We have recently acquired a 1953 Itchenor built "Belouga" cruiser/racer which has been on the hard for about 10 years. She has been surveyed and is in "surprisingly good condition" considering she had about 6 inches of freshwater sat in her hull. The previous owners (she was jointly owned) had her hull sanded, filled, and faired then coated with the West Epoxy GRP system as well as coating her bilge in bitumen (which has been attributed as the reason she's still with us).

I have drained the bilge, cleared the debris and noticed some of the bitumen coming up (after 10 years I'm really not surprised). Some of the timber was damp underneath so I started removing the bitumen and it has dried out beautifully. I'm planning on removing all the bitumen and painting the bilge but I have two questions...

1) Would you coat the newly exposed timber in the bilge with anything, if so what? and why?
2) What Bilge paint do you use on your wooden boats?


I know GRP is not ideal i have read plenty of posts and articles to that fact. However, these are the cards we've been dealt.

 

[Tranona]

As ever - it all depends..... First question is method of construction - hard chine ply, round bilge carvel, clinker, strip plank. West System (which is not strictly GRP) is good on ply, but can be problematic on more traditional construction which is generally more likely to move . You don't say whether the hull has been just coated in West or has a glass cloth skin set in epoxy. Bitumen not good on the inside and best to strip it off as you are doing. If the timber underneath is genuinely dry and no rot (check by simple moisture meter and sounding) then painting with Danboline or equivalent is probably best.

Do you have any photos or a link to the details of the boat as this will help for getting more detailed advice. I vaguely remember the boat as being a Hungarian design built here under licence - but it was a long time ago!

 

[Flying Fox]

As ever - it all depends..... First question is method of construction - hard chine ply, round bilge carvel, clinker, strip plank. West System (which is not strictly GRP) is good on ply, but can be problematic on more traditional construction which is generally more likely to move . You don't say whether the hull has been just coated in West or has a glass cloth skin set in epoxy. Bitumen not good on the inside and best to strip it off as you are doing. If the timber underneath is genuinely dry and no rot (check by simple moisture meter and sounding) then painting with Danboline or equivalent is probably best.

Do you have any photos or a link to the details of the boat as this will help for getting more detailed advice. I vaguely remember the boat as being a Hungarian design built here under licence - but it was a long time ago!

Many thanks for responding.

Firstly Hard Chine Ply, I believe its Honduran mahogany. At least an old article started that.

Secondly I'll check the invoice I've got from the yard from when the work was carried out in 02. I seem to remember it saying two layers of glass cloth skin but i shall confirm.

She's French designed and built under licence so quite close. She's actually the first of the licence built boats built at the Itchenor Yard.

Accueil

 

[pmagowan]

I think it is hard to protect a wooden boat with impermeable layers as a retrofit although this is a great method of part of the original construction and requires a sandwich of wood between 2 layers of GRP giving the relative benefits of both. Older boats generally need to be painted with relatively standard stuff that lets them ‘breath’ to an extent and is also flexible enough to cope with the expansion as the wood takes up. The concern with impermeable layers is trapping water in the wood an allowing rot. Rot will happen but wood is easy to mend and treat if caught early so best to have really good access and inspect from time to time. Most at risk is anywhere that fresh water gets at so deal with leaks from above as assiduously as you would with those from below (as sinking is no fun either).

 

[Tranona]

I have owned sheathed ply boats since 1980. The first was an Eventide Cascover sheathed hull but wooden top and the second a Golden Hind GRP hull and epoxy sheathed deck and coachroof.. If the West was done properly and the hull was completely dry then it is a big plus. The great weakness with sheathed hulls is the hull/deck joint, whether it is wood/wood or wood on GRP. If freshwater gets in and penetrates the end grain of the ply it spreads often without you knowing. I don't know what the hull deck construction is on your boat, but the first thing I would do is a tap test with a small hammer all round just under the toerail and down about10 or 15cm to below the beamshelf. The ply can look fine and have no moisture in but the core veneers can be like cardboard!. However if that occurred before sheathing and hull deck joint sealed with epoxy it may not matter. On my Eventide built in 1963 the top strake below the gunwhale was not sheathed, nor was the deck but just covered with the usual rubbing strake and toe rail bedded in sealer. This was damaged when she broke her moorings in the 1987 storm and I repaired the crumbling edges and epoxied the joint with a solid mahogany rubrail epoxied on. No more problems. however as I described there were patches where water had got in and degraded the ply core and over the years I repaired patches usually by laminating in strips of solid veneers. In some places the decay spread lower down into the sheathed section, but I decided none of it was structural nor visible from the outside.

The Golden Hind has different issues. Historic water penetration from deck fittings such as the pulpit legs, now sealed leaving localised degraded patches, but again decided not to try to replace. other issues are related to localised cracking of the thin sheathing mainly around corners but only one area that has led to water ingress and rot, now repaired by letting in solid wood patches. I doubt you will have have similar problems with the hull. Deck and coachroof usually causes more problems because of the number of joints in the construction. Arguably worse if sheathed because of the potential for cracking of the sheathing, but easier to keep an eye on. I solved the coachroof and deck problems on the Eventide by laying a teak veneer deck! I agree with the above on using conventional paints on unsheathed areas and internally. Both my boats used Danboline on all interior hull surfaces.

Some photos of the Eventide taken in 2019 when I sold her to show that you can keep an old ply boat looking good and performing well - if you keep on top of the maintenance.

 

[Flying Fox]

Thank you Tranona for your advice and guidance with this. The eventide is lovely.

I've just dug out the original invoice from May 2001 and it's as follows.

Hull inverted, sanded to fair condition. Timber treated with eposes penetrating epoxy resin, sanded all seams and cracks filled then sanded. Two layers of RE292 applied with 106 resin. Float filled, sanded and coated with EPU and polyurethane coatings.

Deck (mahogany planks) stripped, sanded and eposes epoxy applied, sanded and filled all degraded areas and applied one layer of RE292 cloth, fill and fair and finish with EPU and polyurethane paint.

So I got a few things wrong but that's the gist. Obviously that was also 22 years ago now.

I'm struggling to figure out photos at the moment.