Mirror Dinghy in Hot Climates

Submitted by Gypsyjoss on Mon, 10/14/2013 - 16:57

Forums:

Hi Guys
I'm thinking of taking a Mirror to Greece on the roof of a Ford Focus Estate, having fond memories of the one we used to have and transport on top of my Dad's A40. We're basing ourselves at a little coastal resort on Evia for a couple of months a year and the idea is to have a safe but fun inexpensive sailing dinghy for the grandchildren aged 2 to 11 and me to sail, go out fishing etc.

a. Do you think the Mirror is a good choice for the envisaged use?

b. Will the standard plywood model survive the extreme of temperatures from 0 degC in Winter to 40degC in Summer, without falling apart, or do I need a GRP model, and which one?
When not in use, it's likely to be stored in the open under a cover.

Cheers

Pete

mirrorpete

Mon, 10/14/2013 - 18:34

Hi Pete,
I live in Canada where the temps in the winter go below freezing every year. I keep my Mirror in the garage and these temps have had no effect. It can get very hot in Canada, but I have no recollection of reaching 40 C. My Mirror is the standard wood variety; I built it in 1983 and it is still water tight and I have never had to reconstruct it.

Common sense dictates that the Mirror should be bone dry before you hit freezing temps. You would not like to have any moisture freeze and expand which could cause damage.

Pete

curlew's picture

curlew

Mon, 10/14/2013 - 19:39

My Mirror stays outdoors all the time. It is really important to ensure that the cover really works and will not blow open or leak. Tarpaulins often develop little holes. I find that having the boat steeply sloping on a hill helps a lot, as the water runs off. If water collects in puddles on the cover, it will get in through any pin hole. I have also found that two tarpaulins is a good idea, as a hole in one will not line up with a hole in the other. It is a good idea if wind can somehow blow through the boat under the cover.
If you suspect rot anywhere, I suggest soaking it in blue antifreeze, then let it dry for 48 hours and if necessary, use epoxy resin for a repair.
I found with my boat that it had been stored upside down, and rot had started on the underside of the gunnels, where water can be trapped.
As you are in a hot country, obviously try to find a place out of direct Sun, as this would push temps much higher than 40C.
David

sail_and_oar's picture

sail_and_oar

Tue, 10/15/2013 - 05:53

A normal Mirror is made of plywood, treewood, epoxy (or polyester), glass tape, and a few metal fittings. Early models may have been built using other glues as Epoxy wasn't very common back then.

I don't think any harm will come to any of the above materials through high or low temperatures. Some people claim epoxy loses some of it's strength at higher temperatures but it seems to have become the most common boatbuilding adhesive worldwide.

Over the last 10 years my 1974 Mirror built with polyester has endured gross abuse and has come through it surprisingly well. It gets used all year and is stored outside. I've had to replace the centreboard case, do some retaping and scarf new bits in the inner gunwales and floor battens but I find it's resilience quite a surprise.

If you were planning on leaving it there for 10 months of the year unattended an automatic bailer will allow any water to drain away. The spars will all fit inside the boat under a standard trailing cover to protect the varnish. Support the cover underneath so it sheds water. Mice can sometimes damage sails. Store them safely indoors.

I wouldn't worry about it. Buy a reasonable Mirror, try to use it a lot and keep an eye on it. If it begins to give up the ghost later on you should get plenty of warning.

Cliff

PuffinInTegel's picture

PuffinInTegel

Wed, 10/16/2013 - 12:59

Wooden Mirrors, even if I do prefer these, do require much more tender loving care than GRP boats. I've no idea whether GRP boats are heavier than well-maintained woodies. Check that your roof rack will be adequate before buying the boat.
Personally I have no major problems with "Puffin" on the roof of a Renault Scénic :
.
The round shape of the car means that the two rack traverses are a bit too close together for my liking and I tie the painter to my front tow eye to reduce wobble ;-{) You should not have that problem with an estate car / station wagon.
As you plan to keep the boat at a location where you do not live permanently, I believe a GRP hull would suit your needs better. It's also less likely to be damaged by unexperienced children messing around in it on their own (mine went out rowing on their own when the oldest from the time the oldest was around 12), which they will probably want to do at some stage.

Gernot H.

joeb

Mon, 10/21/2013 - 21:43

Hi Gernot, I considered transporting my mirror on my estate car roof but was too nervous in the end. I have a roof rack which is rated for 90kg which is enough when stopped but what happens if I need to break sharply? How can the hull be strapped down securely enough?

Joe

mirrorpete

Tue, 10/22/2013 - 01:29

In addition to straps across the hull anchoring the Mirror to my roof rack, I also anchor the bow to convenient straps that I installed just under the hood and which hang out over the hood. I also anchor the stern to the back of the car, in my case the trailer hitch.

Pete

mirrorpete

Wed, 10/16/2013 - 16:09

I agree with everything Gernot says above. However, one should add that woodies are easier to repair than GRPs in case of damage to the hull.

Pete

62816inBerlin's picture

62816inBerlin

Thu, 10/24/2013 - 09:06

Joeb:
Remember your boat gets wider behind the front strap, so it's unlikely to slip under it if the strap is really tight. If your rack is rated for 90kg it is more than adequate, provided it is mounted on the car correctly. The spars need to be secured well against slipping forward, though!
Cheers,
Gernot