256 Hrs – I’ve Got a Wobble On!
Here’s the culprit, This stern panel is about 2cm low at bulkhead 7. You can see the thick band of epoxy at the top where I have started to fill. Thanks for the comments guys, its reassuring to know that these things happen to everyone but I am still really annoyed with myself because I don’t understand why I didn’t see it when I dry fitted and although it can be dealt with I shouldn’t have let it happen.
To add to my headaches I have now have the infamous ‘Wharram Wobble’ I was expecting it, I had read about it, Jacques had commented on it and I had printed some stuff from TheMultihull forum about it. Basically what happens is that the stresses in the plywood cause ‘ripples’ in the edge of the ply where it is not fixed to a stringer. There are many solutions the most popular of which seems to be fixing an additional stringer on the inside edge. I will read up some more and decide on my tactics later. It’s hardly surprising this has happened given the tension these sheets are under. You may recall I mentioned the Spanish windlass technique I used, well you can see this in the photo. The wire was tensioned so much it sounded like a guitar string! They worked though, I am mighty relieved that when I released them today the panels stayed firmly in position, incredible stuff this epoxy!
I spent some time tonight doing a bit of filling and having a good tidy up. I have positioned and prepared the last stern section panel ready to fix tomorrow ( in the right place this time!) When that’s done I have one lower hull enclosed. My plywood supplier is getting new stock in next week so I am hoping that it is the right quality this time so that I can get that issue resolved. It’s not that I really need it at the moment but its nagging at me. I am definately in one of the most challenging periods of the project so far. I have had it pretty easy up to now but this is hard going. I am looking forward to getting this final panel on tomorrow and then spending a bit of time on the less challenging job of filling, sanding and fairing for a bit.
Indecently whilst reading up on hull wobble solutions I came across a post that said Hanneke had approved an option of fitting hull panels individually instead of pre-joining them as shown in the plans. I wish I’d seen that earlier! I am beginning to realise that strict adherence to the plans may not always be the best way forward, trouble is I don’t have the knowledge to decide if an alternative is likely to give me problems later. Ah well I’ll just keep slogging away, even if I do take the long way round occasionally!