Allowing mirrors to be built from plans

  • Simon Lovesey
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26 Feb 2006 19:13 #11609 by Simon Lovesey
Replied by Simon Lovesey on topic Allowing mirrors to be built from plans
Although there are several other classes who allow their boats to be built from plans, we should not underestimate the additional workload this would put on MCA, both to change the rules and then subsequently to administer the distribution of plans etc. It would certainly make measurement more complicated, even with kit builds it is hard enough to find a measurer for a new wood boat, this is likely to cost more.

The cost for plans and royalty is likely to be around £200, with the costs of kits falling (Duffin £750), which include build fees, the saving is not massive, particularly when you allow for wastage and cutting your own panels etc.

So the question to all members, is do we want to devote a considerable amount of MCA limited time, resources and money to something that may only bring marginal benefits ?

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  • ASW
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26 Feb 2006 19:48 #11610 by ASW
Replied by ASW on topic Allowing mirrors to be built from plans
Simon with reference to measurement, it only took me an hour to check our Mirror against the RYA measurement sheet. What extra measurements) would be involved. Most are done by observation ie does the .... comply with rule .... resulting in a tick box.
I fear that this is being viewed at a higher technical level than the boat demands - it`s a simple construction hard chine dinghy - what could be more simple?
It only takes an hour to measure a Fireball Hull with 6 measurement stations and another set of chines.
It`s good to talk

Andy

ASW Boatbuilding & repairs. 07966 513147

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  • Houli2
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26 Feb 2006 20:26 #11611 by Houli2
Replied by Houli2 on topic Allowing mirrors to be built from plans
We had a new Mirror built about 14 months ago - I've just found the measurement documents that we had to submit to the RYA - there are SEVEN A4 pages of them filled with figures. It took considerably longer than an hour to get it measured properly.

Clare

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26 Feb 2006 23:56 #11612 by Trevor Lloyd
A £350-500 saving is a lot of money to some people it could equate to as much as a suit of sails, not to be sniffed at! Yes it is a hastle but if it brings in more paying members to the MCA isn't that a good thing? It may open the class up in more depressed countries.

N2O

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  • ASW
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27 Feb 2006 05:05 #11613 by ASW
Replied by ASW on topic Allowing mirrors to be built from plans
Clare, granted it does take longer than an hour for the whole boat including rig, sails & foils - we are only talking the hull dimensions here- just the first 3 pages.(items 1 -39 on the measurement sheet)

Andy

ASW Boatbuilding & repairs. 07966 513147

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27 Feb 2006 08:33 #11614 by Paul Hansen
With regards measuring when we had our boat measured it took about 3 hours to measure the hull, as Houli said there are many measurements to check.

Paul

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  • Flycatcher
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27 Feb 2006 08:41 #11615 by Flycatcher
Replied by Flycatcher on topic Allowing mirrors to be built from plans
Excuse me if I'm being dense early on a Monday morning - but sureley whether measurement takes 1 hr or 5 hrs is not really relevant. Since the same rules and measurements apply - whatever the method of construction.

Tony
M61950/23044

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  • D Hughes
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27 Feb 2006 23:55 #11619 by D Hughes
Replied by D Hughes on topic Allowing mirrors to be built from plans
I think this has been one of the best topics for a long time...
If I'm correct? then my 64000 Mirror, repaired using the correct 3ply Gaboon, (BS1088 as used by Bell plywood) Is still in Class as it was originally built before 1991? It still sports it's original licence paid number on the transom. (but thats about the only original bit). The floor is 5 ply (as allowed in the rules). I think if it's been repaired more than a 3rd, it needs to be re-measured. that's not a problem.
Is this boat legal once re-measured to sail in the Inlands?
The ply came from the old Jack Holt factory in Todmorden when it closed down. (they used to make composite Mirror Kits and foils in the early 80's).
Interested to know as I'd like to do an event this year.
I have to say that the Genuine Factory Kit boat I built 70153 (current National squad) Is a nice fast boat, but no different from my current boat, built at a 3rd of the cost

You are right though, you can't get hold of the 5mm 3ply at the moment so I won't be building any more as I have non left.

David Hughes

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Edited by - d hughes on 28 February 2006 00:07:52

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  • ASW
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28 Feb 2006 08:14 #11621 by ASW
Replied by ASW on topic Allowing mirrors to be built from plans
Tony, your spot on, the time is irrelevant.
The measurements are already in place to cater for building a hull within the correct tolerances regardless of the ply type, thickness etc... You don`t even need full size plans as the offsets are in the rules.
A slight change in rule wording would allow boats to be built from scratch cheaply and older boats to be repaired easily with locally sourced materials. It would not need any change in the measurement procedure or administration.
As a further thought, when Guy and his team at Winders start producing Mirrors I will buy a hull in. If these plywood anomalies get sorted I would like to do a composite version with wooden decks, tanks etc... Has anyone done one before? There is nothing specific referring to this in the rules apart from rule 3.4 which pretty much covers all.
Comments welcome.

Andy





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28 Feb 2006 14:09 #11623 by Martin Egan
Thanks Andy, that's cute method, I would never have thought of that. Do you have a clever way of taping the centre join inside the front and back tank, or is the outside taping enough ?

By the way, you are not allowed to modify panel shapes. Rule 1.1.2 states

"Amateur and Professional Builders shall complete hulls using only materials supplied with the Mirror kits (except for adhesives which are optional) and shall not modify or replace any part of the kit except where specifically permitted by these Rules."

On the subject of composite boats, in 1986/1987, Holts (copyright holders) produced 70 GRP hulls. Over a period of 4 years they sold these as composite boats to boat chandlers, garages or as finish at home kits. They were chopped strand mat (so were well heavy)and they didn't measure for various reasons. You can spot them as the skeg and bilge keels were not glass, but varnished mahogany. There used to be one at Poole YC, 68461 "White Dove".

Bell/Widebeam also had a go at a composite hull. This was also chopped strand mat hence also on the heavy side. We have one at Restronguet SC, 69992 "Swan Lake". You somtimes see one or two around on the circuit.

I'm not sure if a composite boat can be measured in under the current rules. It would depend on the ISAF GRP specification (Rule 1.2.3)

Dave, it's possible your boat could be legal for National and Area events under the "grandfathered" rule. When was your 64000 Mirror first certified ? (UK MCA Prescription 14 (b) 2))

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  • D Hughes
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28 Feb 2006 17:46 #11624 by D Hughes
Replied by D Hughes on topic Allowing mirrors to be built from plans
I have sent off an Email to see if it has one registered last week, but no reply just yet.

DH

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  • ASW
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28 Feb 2006 19:49 #11625 by ASW
Replied by ASW on topic Allowing mirrors to be built from plans
Hi Martin,
There is no easy way of taping those joints unless you put an inspection hatch in. You could lay up the tape on one panel and let it cure then use that to bond the other panel to - probably a bit over the to though. Modern epoxy would be strong enough without the tape although it would always be prudent to tape whenever possible.
The rules do state that all hull joints must be taped on both sides on the joint - this may not always be possible during a repair as the cost would outweigh the benefits.

Thanks for the info on the composite boats - although if Winders do the same magic with the Mirror as they have with all the other classes they have touched, I may just buy in a bare shell with decks.
Just about to fit-out my 3rd new Winder Fireball - it would be great to have a Mirror for the boys in the same colour.

Cheers,
Andy

ASW Boatbuilding & repairs. 07966 513147

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01 Mar 2006 19:46 #11628 by Martin Egan
Picking up on cjyardley's point regarding the cost of boats in the 60's and 70's. Younger contributers may be interested to know just how basic the standard boat was, for example;
Galvanised shrouds
Cotton 3 strand main and jib sheets
Hemp (? brown and not synthetic) main and jib halyards, kicking strap, rudder uphaul.
Bullseyes (not blocks) on the mainsheet
Wooden jib fairleads (certainly no cleats !)
Plastic wind-around cleats (HA130 ?) for the halyards
Tiller extension joint was a bolt
Kicking strap was just tied to an eye on the bulkhead
Shroud plates were alloy (HA3)and there were brass (electrolysis !) shackles to fix the shrouds to the plates.

Regarding measurement, if the rules state that the ply used has to be between Xmm and Ymm, then the measurer has to record the facts that were found. It's not a question of only taking a measurement if one is "suspicious". This is one of the reasons why ISAF are so pickey about the wording of rules (for example they don't like the wording "approximately parallel" in our rule 7.1.3)


Another couple of questions for Andy (or anyone else for that matter)

A number of people have talked about finding an alternative to gaboon ply. I understand that gaboon is well regarded in boat building circles for producing strong, lightweight and fairly durable boats. If this is true, then using something else will produce boats that are either overweight or not strong enough or both. Is this true ? Is there an alternative type of ply that would be worth looking at ?

Simon has pointed out that Duffin are now selling hull only kits for £750. How much would a kit or the £25 Trident panel be from ASW Boatbuilding ?

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  • ASW
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01 Mar 2006 21:12 #11630 by ASW
Replied by ASW on topic Allowing mirrors to be built from plans
Hi Martin,
Gaboon ply is really the only type of ply to consider.It`s the size and number of plys that seems to be the problem. Ply is always a nominal size and depending on the source a Nominal 5mm ply can be from 4.7mm to 5.5mm in 3 ply 4 ply or even 5 ply.
The early Mirrors were built of 3 ply of a grade similar to builders ply, with voids in the inner core and very thin top veneers. the inner core acts like a sponge when moisture gets in which is why so many older boats rot out around poorly fitted self bailers.
As far as providing kits or panels - it`s not an area i would want to commercially be doing. The repair work is enough, hence why we stopped building Ents.
The Duffin kit looks good value.
Andy

ASW Boatbuilding & repairs. 07966 513147

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  • angus
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05 Mar 2006 08:58 #11641 by angus
Replied by angus on topic Allowing mirrors to be built from plans
You mention that gaboon is really the only type.

Is gaboon ply the only marine ply that avoids the pitfalls of 'builder' plys? Or is it the best strength / weight ratio marine ply going? Or is it something else.

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