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[jimb]

Hi, a few questions to all classic Phantom owners, past and present. Home built Phantoms, can they be built down to weight, and if so, what is the secret. There seems to be 2 opinion camps; either down to weight or in the 70kg+ bracket. How easy would it be to build a self draining woodie down to weight? and would you have to consider 'space frame' type construction to keep the weight down anyway?

Thanks in advance , Jim Blewett

['One-Pint']

Jim,

Hate to be pessimistic but even John Claridge struggled to build down to weight, although his are some of the lightest woodies made.  Mine was certificated at 2.5Kg over when new.  Many home-builds are tipping the scales at 10-15Kg over or more.

What are you trying to achieve?

AB

[John Torrance]

Jim
Single bottom home builds are easy to get down to weight, self drainers have proved more of a challenge. Some of the lightest woodies have been built by Clarridge, Chapman and Ledger but all seemed  couple of kilos over ( still lighter than the grp boats )
Hope this helps.
John

[jimb]

Hi, thanks for the replies so far.
Question of what am I trying to achieve  .
1. Never built a boat before and since I am sailing a Phantom at present, 993 - GRP, I thought it would fulfil an ambition (plus bring it up to date...)
2. With sailing a GRP boat its heavy!! (think we are talking +15-20kg anyway!!..) Having had a shot of an epoxy boat the feel and performance is noticeable!! 
Hence the questions, can the end result be a boat down to, or nearly down to weight.

Sounds like it can be done, but, by what methods? Special sourcing of Marine Ply to get the lightest sheets possible or 'space framing' the internal structure so that its light, but still holds its strength or ??
Really just looking form some pointers from people in the know as to how it may be achieved.

Thanks again

Jim

[AlexOg]

Hi Jim,

I've got a woody myself and my dad built his own dinghies as a kid (he was Australian national champ in Gwen 12's) so naturally we've had this conversation about twenty times! We reckon you could built one down to within a couple of kilos of minimum weight if you were VERY careful. Using frames then ply over the top is a must if you want to keep stiffness without added bulk (stitch and glue's a nonstarter if you ever want to have a chance of winning a race). You also have to consider the considerable leeway given in the rules for hull shape which would let you tweak it quite a lot. That said it would take quite a bit of work and skill to get a good solid boat. If you look at the Claridge boats you see that John clearly put a lot of time and thought into his design and everyone seems to rage about how stiff they are.

I'd say get some plans and draw it up in something like AutoCAD then sit and have a really good think about the feasibility and engineering of the whole thing. You could skimp on stiffness then just epoxy saturate the whole thing (and you be surprised how much ply will absorb if it's warm) but chances are you're never going to get close to the stiffness and weight of an epoxy foam-sandwich boat. Then again you'll probably save yourself about seven thousand pounds and have the satisfaction of knowing  how your boat works so who knows, it might be worth it!

Alex
829

[jimb]

Thanks Alex for the reply. Question on Claridge boats, the internal self drain flooring, are they all rounded floors as I have never seen one in the flesh??
Plans wise, other then flowing over the measurement rules to get a feel for the tolerance on the dimensions, I cant picture how much leeway there is in the hull shape without, as you say, drawing it up on a 3D CAD program and seeing what drops out.
Not sure if the raw outer hull shape changed any between GRP and epoxy and Vandercraft & Ovintigton. Usually in most classes hull shapes get tweaked within the tolerances based around a winning design. There is a point that if the rules are too open then the end result is a shape which is noticeably away from the original intent of the designers.
Anyway, agreement that space-framing is the right route, doe anyone else have any detail pointers on the subject? Rgds Jim