Hi,
I'm about to start the restoration of Number 2990 a hooligan design made by Hoare. What I would like to achive is to get a  varnish wood loking hull. But the wood is not in a to good state and I think I will probably need to sheat the outside with fibreglass and epoxy. I have been told that the only way to get a result good enough for it to be see through is to use a vaccum pump. 
Have any of you already done this?
If yes, how did you do it?
Thanks for your help,
Philippe

I suspect if the hull is bad enough to need glass sheathing then its time to scrap it. Its normally a technique to get a few more years out of a boat before it hits the bonfire. You get all sorts of problems with damp and rot locked into the wood, all the rest of it. As a cure it tends to be worse than the disease. Epoxy fine with appropriate treatment, but I'd be *extremely* wary about glass. Once its got glass on you won't really get that much of a varnish type finish. In some circumstances I might consider using fibre reinforcement about the inside of a boat, although I'd have doubts about even that on something as intricate as a Merlin, but never the outside. You may also find thislocation useful http://www.cvrda.org/

I have emailed similar comments to you.  It's amazing what you can do when the situation looks really grim!!

Definitely check out our CVRDA varnishing guide and make a post on the cvrda forum - there's a bunch of wood and varnish experts there. When you've done it, join in the events - we link up with the MR vintage wing.

Many later merlins (3400+) have been glassed to provide extra siffness so done properly it is perfectly fine. Certainly my old boat(3442) had been sheathed in woven fibreglass/epoxy and there were absolutely no problems. All the Kevin Driver boats were built new with some form of glass reinforcment (Caused a stir too as i remember!) and none of them have gone rotten.

You will run into problems if you don't get the boat *thoroughly* dry because there will be no way out for the water left in. If you are varnishing it will be blatently apparant if problems are developing becasuse you the wood under the sheath will go black as the ace of spades!

I don't believe class rules limit the weight of cloth permitted anymore, it used to be 100g/sqm and that was perfectly adequate.

I think summing up, the horror stories you hear of boats that have had the bottoms fall out of them have either been done incorrectly or using polyester resin. As with all jobs if you make a decent job of it and use the right materials it will be fine. After all we have been using wooden glass/epoxy sheathed rudders and centreboards for a couple of decades now!

Take a look at the pictures on this website of Pat Blakes old boat 3640 hand built by Laurie Smart. Both hull inside and out where glass sheathed without the aid of vacuum pumps. Take a lookat the glass like finish of the paint job. Speaks for itself!

Mags/

Perhaps you could put a link to these pictures?

http://www.merlinrocket.co.uk/gallery/view_photo.asp?folder=gallery/building_and_repairs/lawrie_smart&file=lawrie_bare_hull.jpg

Cut and paste.

This picture shows 3640 part sheathed.

.

Hi I think youd add too much weight and never get a finish good enough to varnish,paint possibly.If you could email some photos i might be able to advise further. I have restored many old boats but have never resorted to glass sheathing.

As you can see from the Photograph of "Smart Tart" it is possible to sheath and get a good finish it is also possible to get from the better vendors a rough scrim that if applied over bare wood it completely transparent when wetted down and cured,and finished in clear epoxy, my own Cold Moulded Boat with the outer veneer laid for and aft is finished this way and it's not only very beutiful it adds a lot of stability to a wooden finish. However and this is the caveat I suspect it needs professional or careful and experienced amateur application.
Mags is it possible to put spell check on the forum? Or is cut and paste better?

west demonstrate this technique at shows, and will offer advice on how to do it

I have sent a separate email since I am currently refurbishing MR 2789 which is in essentially good condition and was to minimum 98 kg as built with no correctors. I suggest you check the built weight and correctors fitted, if any, on your certificate before adding a sheath rather than a paint finish.

Surely the construction of a new boat using glass sheathing - effectively ply sandwich as opposed to foam sandwich - which I agree is highly effective, is in every way a completely different exercise to using glass to make up for the deficiencies in planking that has deteriorated to the extent that it no longer fulfils its original function? Even discounting issues like locking in rot and damp, there is also the consideration that if the plank to plank joins are no longer structuraly sound there's going to be a tendency for movement, which is going to delaminate the glass from the wood which will... 

I submit that in order to do a proper job of converting the boat to ply sandwich construction you will have to do so much work on the structural integrity of the planking that when you have done the prep there will be no longer a requirement for the glass sheathing!

Most of the 33xx and 34xx boats that were sheathed were done due to stress cracking in the bottom planks which were appearing because of the deteriorating quality of available ply.

It depends on how bad the rot/damp is. As long as you get the wood dry and sound i can't see a problem, and certainly 3442 was not sheathed over the lands themselves as it would be unecessary due to the double thickness ply.

Hi everyone,
Thanks for all your comments, but I think most of you have not understood me. (I'm sorry I'm french so...) I didn't meen to say the wood was roting away and all soft. Apart from two planks that where broken by the trailer rollers, the boat is in fairly good condition. I will replace the broken planks and the hull should be fine.
Only 30 year old wood is bound to be slightly less resistent than it was when new and all though it seems to have been well built,  but it is a bit light. Of course this is probably how most merlins are built, but I sail in the sea where there are lots of big waves and usualy a lot of winds. I have a tendensy to sail boats hard and I don't want to spend more time than necessary in the workshop instead of on the water. This is why I want to sheat the outside of the boat. To make it more resistant to shock.
For those who are concerned by traping the rot inside, they need not worry. This technique is used a lot and is absoluntly fine if the boat is left to dry for long enough. Rot only apears with over 20% moisture in the wood so if the moisture is under 15% it will never rot once inside the epoxy. Besides its when the wood is dryest that the epoxy penetrates the deepest and is the most efective.

My question was only to know if anyone had ever achieved a varnished look with sheating and if they did how?
In any case I will be starting tests so I will keep you informed.

Philippe

As I said in a previous post, Laurie Smart, a boat builder here in the UK glass sheathed Pat Blakes old boat 3640 'Smart Tart', (07976 536922. As I followed the build process of this boat for an article when I was the Merlin magazine Editor I noted that when the sheathing was complete the whole of the hull was skim coated in what appeared to be an epoxy type filler and then faired to a very, very smooth finish. Several coats of 2 pack undercoat applied, faired each time, then a number of  2 pack gloss coats applied. The finsih, bearing in mind by hand, was astonishing, you would even have felt happy to eat off it, it was that good!

If i remember righly SP systems website gives some good tips on how to sheath hulls using their epoxy systems, worth a look.

I have lots of pictures of 3640 being built if you want me to email you any showing this process?

Richard

Marinewear (UK SP Systems dealers) exhibited a varnished canoe at their Southampton Boat Show stand with a varnished interior which had been glass sheathed. They used a specific type of binder on the glass that disolved with the epoxy to give an invisible finish. The only area where you could tell was where some of the matt overlaps were not managed well. I am sure that they can advise futher - tel. +44 (0) 2380 330208, web - www.marinewear.com

I am told that 3 coats of SP320 will give a good build thickness and a single coat of a varnish for UV protection is a good way to proceed.

www.marineware.com works better :)

Philippe,

Vous êtes basé où; nous avons 2 Merlins, dans l'Avesnois.

Just thought I'd add a bit of international flavour to this thread.

How long before we see a Merlin World Championships?

ISAF recognition requires fleets of 20, in 4 countries. Does Scotland count seperately in this case? Pity we can't count Wales too...

Je suis a Calais.

I would like to have the pictures if you can send them to me.

ISAF will recognise a country as a country if it has its own sailing federation. so if Wales, Ireland, Scotland and England have sailing federations and 20 boats sailing you wouldn't even need France. But I doubt Wales and schotland do.

I took the boat to the sailing club last week as they have beter facilities to work and met a guy who said:
"Thats funny I have nearly the same boat in my garage. I've had it for several years and always wondered what it was."
So maybe I will not be the only merlin around!!!

Philippe

Yves Jambon of Dériveur Services, St. Malo(who some of you may remember from the Easter trip a few years ago), picked up a number of older Merlins for peanuts and sold them to new and mostly innocent owners who were impressed by the woodwork; most of these were in Brittany/Normandy, but it's not clear how many of these have ever been sailed properly. I heard of at least two that had been wrecked, and others had been bastardized by fitting them with trapezes & suchlike. We never come across other Merlins over here; I think the last one was a Ghostrider which was based in Bruxelles for a short while. However many years ago, a former crew of mine sailed his small yacht to Australia, and sent me a snap of a Merlin he found sailing off the coats of Salala, Oman. I rather think I sent the photo to the mag. and never got it back!

If the class is ready for another 'foreign trip' for some at least European Champs, I recommend Grevelingen,- see [email protected]

Do you not fancy the trip to Jersey in July then 25 boats signed up so far. See next years fixtures. Bloody close to St Malo too, £50 return ferry trip.

To be honest Hywel, I hadn't seen this. Of course, if you're going to have the same rowdy evenings that kept us awake at Salcombe a few years ago, we might give it a miss!