Wooden boat 4450 – new deck, etc
16/09/2020 at 11:36 am #20848Chris DavidsonParticipant
As my boat will be 60 years old next year (36 with me), I’m going to try and carry out some restoration:
Epoxying the whole inside. The deck is off and I’ve stripped the varnish off to bare wood. Is one coat of epoxy sufficient followed by lots of varnishing?
Series 1 mast step conversion. I have the plans. I have a wooden mast. Does this make any difference?
Bow buoyancy chamber. I’m going to fit a chamber with a shelf between the top and the deck for stowing. Do I need to fit a floor for the chamber? Are there any drawings of how this is fitted?
New deck. I have 5 mm Robbins Elite. My old deck was c.2 mm. I’ll need to fit new centre strips in the bow and stern decks so the new deck is flush. Any views?
I realise that these topics will have been covered before so links to those posts will be great.
16/09/2020 at 12:25 pm #20853
First, your original post was initially suppressed, because it was almost exclusively formatting commands. I would guess that you probably wrote it in some other program and then copied and pasted it to here, and that is what then usually happens in such situations; unfortunately the software of this website does not recognise Word commands, or those of other wordprocessing programs. I have recovered the post, and have deleted all the formatting commands while trying not to delete any of your intended text, but please check that all your intended text has survived the editing.
Second, your image has not appeared because it exceeded the permitted file size; that limit is set by the system, and is applied automatically, and we cannot override it. Could you please re-size the image, and then upload it again.
I am just about to go out for the rest of the day, but I will try to respond to your queries either this evening or tomorrow. No doubt others will also respond.
- This reply was modified 1 month ago by Oliver Shaw.
16/09/2020 at 7:57 pm #20858
Epoxying: I would indeed expect one coat of epoxy plus several coats of varnish to be appropriate. I would aim for at least six coats of top quality varnish, rubbing down between coats.
The headline epoxy is WEST, but there are various others, and the major yacht paint manufacturers (International, Hempel, etc.) offer epoxy primers. One which I have seen advertised (regularly, in Classic Boat), but have not yet had occasion to use,m although it looks sufficiently impressive for me to consider using it in future, is Smith’s Clear Penetrating Epoxy Sealer, from Make Wood Good, https://www.makewoodgood.co.uk/product/cpes-clear-penetrating-epoxy-sealer/.
The WEST System resin is primarily designed for bonding and laminating, for both of which it is truly excellent. However when used as a primer for varnish I have found that it is physically hard work to subsequently sand it really smooth, even using an orbital power sander. I have also found that it needs to be left far longer to cure before painting or varnishing over it than at first appears; if varnish is applied too soon after it has apparently cured, the varnish will not cure properly. Part of the solution may be to remove the “amine blush”, as explained in the Gougeon instruction manual, but I nowadays reckon on leaving the epoxy for at least 48 hours (even in high summer, and perhaps a week in colder temperatures) after it appears fully cured before I apply any paint or varnish over it.
Even with the wood thoroughly epoxied, including on the “blind” side, I would be hesitant to use 2-pot paints and varnishes; I have found in the past that if there is any movement at all at the edges of the ply panels, two-pot paints are too hard and too inflexible to tolerate the movement, so they crack along the joints in the ply, and that allows water to get in underneath the paint or varnish. Therefore I always advise against 2-pot paints and varnishes on vintage GP14s, although they are excellent on new construction.
However I discovered that problem before the modern trend of first coating the wood in epoxy became mainstream; so I have insufficient first-hand experience of epoxying and then varnishing a vintage boat, anhd the jury is still out on this question.
An excellent alternative to overcoat WEST epoxy is top of the range conventional paints and varnishes. I happen to be most familiar with the International Paints range, from which I would choose Toplac enamel and Schooner varnish (not to be confused with Schooner Gold, which is a very different product, and personally I don’t like the way it flows out – or doesn’t). Schooner Varnish is a tung oil product, and is (or has been – I have not checked the current documentation) described by the manufacturers in terms which put it second in gloss only to their two-pot product, and better than any of their other conventional varnishes, and of very high durability. However the other yacht paint manufacturers no doubt offer similar products, and I do not hold a brief for any one manufacturer as against another. Indeed on my GRP trailer-sailer yacht I have used Hempel Monourethane on the cabin and cockpit, and have been very pleased with it.
Mast step conversion: the conversion raises the position of the mast step (by 12 cm, from memory), as in the Series 2 boats, and therefore shortens the (metal) mast by that amount in order to keep the sailplan at the same height; this converts the Series 1 mast into a Series 2 mast. For identification purposes, amongst other reasons, the type of mast foot and step are then changed to the pattern for the Series 2 boats.
Given that you have a wooden mast, you would seem to have a number of options, which include:
- Shorten your wooden mast by the appropriate amount, (and ideally change the foot and mast step). This will inevitably mean that your mast is no longer usable on any other GP14, and it will also take the mast out of class, both of which you may perhaps consider a very serious drawback. You will also very probably have to move the lower sheave boxes.
- Fabricate a (removable) metal tenon fitting to enable your mast to sit in the Series 2 step (which is a particular track fitting), and just accept that when using the wooden mast your sailplan will be that much higher in the boat; you will need new, and longer, standing rigging in order to do this. Keep the wooden mast for “high days and holidays”, and acquire a secondhand metal mast for everyday use; if the latter happens to be Series 1 (i.e. with a square foot) convert it to the Series 2 format (tenon foot, and shortened by the appropriate amount). Make up suitable cheek pieces to line the slot in the deck when using the metal mast, because it is 10 mm(?) narrower than the wooden mast. If converting what appears to be a Series 1 mast, do measure before you cut; I did once buy what purported to be a Series 1 mast, and which indeed had the square foot of the Series 1 design, but which had nonetheless been shortened to the Series 2 length – so beware, and measure!!
- Provided the structure is in fully sound condition, decide not to do the mast step conversion, and simply limit your rig tension accordingly. A fully sound vintage boat should be strong enough to handle rig tensions available from any tensioning device up to and including a Highfield lever; but the tensions obtainable from a muscle box or a powerful cascade tackle would be a grossly unfair load on a boat which was never designed for such loads.
Hope this is of help,
16/09/2020 at 9:52 pm #20859
New deck: I am very surprised if you old deck was indeed as thin as 2 mm, but it may well be thinner than 5 mm. It is therefore very likely that the surface of that part of the kingplank between the two sheets of ply will be lower than the face of the ply. There are initially two options, with the second then splitting into three further options.
Option 1, if you wish to preserve the original cosmetic feature of a visible (part of) the kingplank you will need to built it up to the required thickness. That might be done by preparing an accurately flat surface, and then glueing on one or more layers of veneer, or alternatively by planing the wood down, possibly to flush with the rest of the kingplank, before then glueing on a fillet of hardwood 5 mm thick (or fractionally thicker if you are then prepared to very carefully plane it back once the deck is on so that it becomes absolutely flush with the plywood.
Option 2 is to dispense with that visible part of the kingplank, and just plane it flush with the rest of the kingplank. From this point you then have three alternative ways forward; either (1) bring both sides of the deck right up to the centreline, leaving a ply joint as the centreline, or (2) use a single piece of ply (with no centreline joint) for the entire foredeck, or (3) as a variant on the first option incorporate a decorative inlay as per the attached photos.
- This reply was modified 1 month ago by Oliver Shaw.
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17/09/2020 at 9:36 am #20863Chris DavidsonParticipant
Many thanks for your comprehensive advice.
I’m going to keep my existing mast arrangement and use a single piece of ply for the new deck.
That keeps matters simpler!
ps My apologies for not reading the forum guidelines first.
19/09/2020 at 7:22 am #20865ArthurParticipant
Having done the deck on 5942 last year, I can assure you that the ply is not 2mm, but much closer to 5. While I have done a lot of building with Epoxy, I only used it on my GP as a glue. Rather than nailing the deck down, I used thickened epoxy and many 20 litre containers full of water to hold it down while it set and hardened.
I did not “seal” the inside of my boat with epoxy, but instead used white oil based marine paint on the underside of the deck and on the inside of the hull, leaving the ribs and stringers in their varnished state. You can catch a bit of it here with my included pictures of my forward buoyancy and storage compartment I built.
I still had some cleaning up to do in that picture, plus more varnish on the bulkhead. The hatch is a large Compression Style Deck hatch, it requires no hinges or latches, but turning the two levers screws in two arms that pull it tight to it’s frame, rendering it watertight.
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