Need help with Mirror 10 restoration project!

[jaybeegee]

Hi all,

I recently picked up a Mirror 10 as one of my many retirement projects but I may have bitten off more than I can chew with this restoration!

Before I start pulling things apart or spending money in the wrong places, I'm trying to understand exactly what I'm looking at. While inspecting the hull, I noticed what appears to be a smooth S-shaped distortion or groove on the underside near the centreboard slot. I'm not sure whether this is part of the original hull shape, the result of an old repair, wear from years of use, or something that requires more serious attention.

The hull feels generally solid and I haven't found any obvious cracks but as a complete novice to wooden dinghy restoration I'd really appreciate some guidance before I start dismantling anything.

Photos can be found here.

A couple of questions:

• Does this distortion look familiar to anyone with Mirror restoration experience?
• Would you recommend any further inspection before deciding on repairs?
• As a first step, would you typically strip the boat down and sand everything back, or is there a better approach?

Any advice would be greatly appreciated.

Many thanks,

JB

 

[bajansailor]

Welcome to the Forum JB.

That S shaped distortion aft of the daggerboard case should not be there - there should be a smooth run aft to the skeg at the stern.
As a first step, I think it would be worthwhile to sand off all the loose paint and varnish in this area (on the inside and the outside), and especially all the flaking paint around the daggerboard slot, to see if there is any rotten wood in this area that is hiding under the paint. .
Can you then see any damages that were previously covered by paint?
I am wondering why the hull shell appears to have been 'set in' aft of the dagger board case. Could this perhaps happen if the daggerboard hit the bottom while sailing reasonably fast?
Can this possibly be related to how the transverse thwart (seat) on the aft side of the daggerboard case is a bit askew - it appears to have sheared away from it's support attached to the portside buoyancy tank.

There appears to be many coats of paint on the hull, with at least 4 different colours visible. It would be a big job to sand it all off, but it could be worthwhile doing this using a chemical paint stripper and a scraper initially, and then sanding it finally.

In the photos I can see an alloy mast with a timber gaff for the gunter mainsail - do you have a boom as well?
I can see a wire stay with a turnbuckle on the end - are there two of these for the side stays, or is the turnbuckle for the forestay.
We had a Mirror in the 70's, and the side stays were simply attached to the padeyes on the coaming with shackles, while the forestay was tensioned with a rope lashing to it's padeye.
Are the sails still in reasonable condition or are they rather brittle (can you poke a finger through them)?
If they are reasonable, does the jib still have it's plastic hanks, and the mainsail it's battens?

 

[HelmutSheina]

It will need paint removed in order to assess viability, which appears borderline from photos. I prefer a heat gun and scraper, others do it differently. I would suggest chemical strippers are a last resort. This document might be useful, and best wishes with your project.

https://www.boatdesign.net/attachments/mirror-16-building-instructions-edited-pdf.173308/

 

[wet feet]

I'm guessing that the distortion of the bottom is the result of leaving the boat on a trailer with a leaky or no cover.The weight of water will probably be the cause of the distortion.If you have the time and inclination,the boat can probably be brought back to life but don't expect to be sailing for a while.Effective chemical paint strippers and polyester resin are not a happy mix,there are versions sold for use on fibreglass and they don't do as much damage or work as quickly.Many of the older or neglected Mirrors I have seen have soft spots around the brace across the bottom panels or just forward of the stern buoyancy tank,so take a look at those areas.

 

[jaybeegee]

I'm guessing that the distortion of the bottom is the result of leaving the boat on a trailer with a leaky or no cover.The weight of water will probably be the cause of the distortion.If you have the time and inclination,the boat can probably be brought back to life but don't expect to be sailing for a while.Effective chemical paint strippers and polyester resin are not a happy mix,there are versions sold for use on fibreglass and they don't do as much damage or work as quickly.Many of the older or neglected Mirrors I have seen have soft spots around the brace across the bottom panels or just forward of the stern buoyancy tank,so take a look at those areas.

Thanks very much, that's really helpful. It had indeed been sitting outside on an old trailer for many years so your explanation certainly makes sense - I did think that it could have been a hit with the rudder down. I'll have a closer look around the brace and for any soft spots. I also appreciate the tip about paint stripper and polyester resin. I'm in no rush with this one, so I'd rather do it properly than quickly!

 

[jaybeegee]

It will need paint removed in order to assess viability, which appears borderline from photos. I prefer a heat gun and scraper, others do it differently. I would suggest chemical strippers are a last resort. This document might be useful, and best wishes with your project.

https://www.boatdesign.net/attachments/mirror-16-building-instructions-edited-pdf.173308/

Thanks very much for taking the time to reply and for sharing the building instructions - that's a fantastic resource which I had never come across before. Agreed on the need to understand what's underneath before deciding how far to go with the restoration and that will be the start of the project. I'll also bear your advice on paint removal in mind and avoid jumping straight to chemical strippers as already mentioned by someone else in the thread.

Much appreciated!

 

[jaybeegee]

Welcome to the Forum JB.

That S shaped distortion aft of the daggerboard case should not be there - there should be a smooth run aft to the skeg at the stern.
As a first step, I think it would be worthwhile to sand off all the loose paint and varnish in this area (on the inside and the outside), and especially all the flaking paint around the daggerboard slot, to see if there is any rotten wood in this area that is hiding under the paint. .
Can you then see any damages that were previously covered by paint?
I am wondering why the hull shell appears to have been 'set in' aft of the dagger board case. Could this perhaps happen if the daggerboard hit the bottom while sailing reasonably fast?
Can this possibly be related to how the transverse thwart (seat) on the aft side of the daggerboard case is a bit askew - it appears to have sheared away from it's support attached to the portside buoyancy tank.

There appears to be many coats of paint on the hull, with at least 4 different colours visible. It would be a big job to sand it all off, but it could be worthwhile doing this using a chemical paint stripper and a scraper initially, and then sanding it finally.

In the photos I can see an alloy mast with a timber gaff for the gunter mainsail - do you have a boom as well?
I can see a wire stay with a turnbuckle on the end - are there two of these for the side stays, or is the turnbuckle for the forestay.
We had a Mirror in the 70's, and the side stays were simply attached to the padeyes on the coaming with shackles, while the forestay was tensioned with a rope lashing to it's padeye.
Are the sails still in reasonable condition or are they rather brittle (can you poke a finger through them)?
If they are reasonable, does the jib still have it's plastic hanks, and the mainsail it's battens?

Many thanks for taking the time to write such a detailed reply - I really appreciate it.

Your observations are extremely helpful, particularly regarding the distortion and the thwart, as those hadn't occurred to me. The boat is garaged separately from my home, but I went back to look at the photos and I can now see why you mentioned it.

The daggerboard theory is certainly plausible. I have seen the aftermath of a Dufour 27 clipping a reef and the damage looked surprisingly similar, although at this stage I'm keeping an open mind until I've exposed the timber around the affected area.

At the moment I can't see any obvious damage, but as you suggest I'll start by carefully removing the loose paint around the centreboard slot and inspect it thoroughly, both inside and out, before dismantling anything further.

I do have the boom as well as the alloy mast and wooden gaff. Over the weekend I'll lay out all the rigging, sails and fittings, check the stays, battens and jib hanks, and post an update with some better photos. I'll tag you if that's okay, as I'd really value your thoughts.

One final question - I have both a heat gun and access to chemical paint stripper. Given the age of the boat and the previous possible fibreglass repairs, which approach would you favour?

Thanks again for sharing your experience.

cheers
JB

 

[bajansailor]

One final question - I have both a heat gun and access to chemical paint stripper. Given the age of the boat and the previous possible fibreglass repairs, which approach would you favour?

I had previously suggested using a chemical paint stripper, but after seeing the posts by Helmut and Wet Feet above, I would agree that a heat gun and a sharp scraper would be a better way to go.

Re the hull distortion, Wet Feet's suggestion about water sitting in the hull for a long time is very plausible - when you first found the boat, was she stored right side up, with a tarpaulin over her, or was she completely exposed to the elements?

 

[jaybeegee]

Thank you.

No clue how she was stored in the long term but for the last 12months she was stored outside and right side up on a trailer with the sails folded in the middle and other junk over it

 

[jaybeegee]

@bajansailor @HelmutSheina @wet feet Many thanks again for all the advice. I have just uploaded a few extra photos in the same repository here and they've ended up at the bottom of the gallery for some reason and was sure most recent on top but anyway!

The good news is that the mast, boom, gaff, rudder, daggerboard, sails and most of the rigging appear to be in reasonably good condition.

Several of the seams and fillets also look like they'll need attention.

The hull is what concerns me most.

One thing I discovered today is that if I push firmly from the inside against the S-shaped distortion, the hull actually flexes and then springs back into position. That makes me think something structural has let go rather than this being purely cosmetic.

I also tried tapping around the area and gently probing with a screwdriver. I couldn't find any obviously soft or rotten timber, although I appreciate the paint still needs to come off before I can be certain.

Before I start stripping paint, does the flexing itself point any of you towards a particular failure? Would your next step simply be to remove all the paint in particular around the affected area and identify exactly where the movement is occurring, or is there anything else you'd check first?

Many thanks again for all the help

 

[HelmutSheina]

The biggest issue with chemical stripper is removing it completely after usage. One tiny drop will sabotage whatever you put on top of it. Best for surfaces that will handle a Gurney blast, and can still be problematic then.

A heatgun can quickly scorch, so caution is essential and start somewhere a ding or sear will be less critical. Scraper quality is important, and ones that are drawn rather than pushed can be gentler, though you will probably require both types.

Fresh water pooling is the enemy with rot, so the recent outside storage may have condemned the hull.

If you assess that she is unfeasible to repair, the project could morph into a new build, where the range of available plans is enormous, so have a bit of a ponder on your intended usage if the Mirror is looking sad.

Here is Duckworks selection for open sailing dinghys ≥14'. This is one category on one site.

Plans by type - Sailboats - Open Sailboats 14' up - Page 1 - Duckworks

duckworks.com

 

[bajansailor]

One thing I discovered today is that if I push firmly from the inside against the S-shaped distortion, the hull actually flexes and then springs back into position. That makes me think something structural has let go rather than this being purely cosmetic.

Would it be feasible to epoxy bond a longitudinal timber stringer on the inside of the hull in way of the distortion after the hull shape has 'sprung back' to stiffen it up?
In similar fashion to the transverse section of timber on the cockpit floor.

Several of the seams and fillets also look like they'll need attention.

This is not surprising - it is probable that the seams were done with glass tape and polyester (rather than epoxy) resin.
Our Mirror was #20628, and she was built from a kit in the late 60s; the kits were produced fast and furious back then, so your kit number #45534 was probably only a few years later.

The Mirror kits were all originally supplied with sails by Jeckells in Wroxham, England; I see that your sails were made in Malta, so they will be much newer.

 

[wet feet]

I very much doubt that any part of the structure has let go,there isn't much structure in the first place as one of the design goals was keeping the weight down for car topping.If,as I suspect,the distortion was caused by the trailer supports the boat must have sat for quite a while and the bottom has now taken a set with the result you found.It isn't likely to return to the shape the designers intended without some encouragement.Were it my project I would build a pair of boat stools to fit the hull at the location of the main forward bulkhead and the aft cockpit bulkhead and try to find a spot to stand the boat that would allow me to use shores from above to push the boat back to a fair shape.Having hopefully and eventually achieved this happy state I would then shape a couple of longitudinals to bond to the inside surface to help retain the shape.They needn't be particularly massive as the hull is only 4mm ply as I recall. Something from perhaps 20mm square wood with the top corners rounded ought to be sufficient and the interior surface would need to be stripped to bare wood in the the intended location.The polyester resin on the seams can last well if the boat is looked after but epoxy will be better and the quantity needed won't be great unless you lose some due to the heat of the location and premature curing while you are working.

 

[jaybeegee]

Hi All and thanks for taking the time to comment on my post - it has been incredibly helpful and thought I would provide a quick update.

I have been able to confirm that the original plywood is still fundamentally sound and whilst there is evidence of damage there is no rot!

So the proposed approach is :

• Strip the paint around the damaged area and inspect the plywood and seams thoroughly.
• Use a wooden piece of wood spanning the gunwales and a small bottle jack inside the hull to apply very gentle controlled pressure to ease the S-shaped distortion back towards its original shape (not force it).
• Once the hull is back where it should be, replace the floor battens with new ones that are longer, wider and thicker to help stiffen and support the hull.

The thinking is to preserve as much of the original structure as possible before committing to replacing the bottom panels.

Seems to work in principle but not sure in practice!

Any thoughts on correcting the hull distortion like this? I've attached a quick sketch of the proposed method together here with a few more photos of the hull here.