USA Hazardous Boat Building Project - June 2014 Update
15/07/2014 21:49:41 Julio Arana
I hope everyone is having a great sailing summer. In case you wonder what I've been up to, in June I finished painting the inside of the hull, finished the deck frame after correcting a mistake I made, and got a good start on the deck work.
Special thanks to Keith Callaghan, Miles James and Jeremy Deacon for helping me sort out the deck work to get it going.
P.S. Congratulations James Gibbons for purchasing a set of plans from Keith to build a Hazardous 150! I look forward to your project updates.
15/07/2014 22:31:15 Jez3686
Smashing job Julio, looking good!
16/07/2014 09:14:19 James Gibbons
Looks great Julio. Cannot wait to start mine. At what point does the boat get a sail number and have you thought of a name for the boat as yet?
16/07/2014 14:24:26 Julio Arana
Thank you, Jeremy. I'm using your photos of Panatella as guidance and inspiration. Beautiful work you did!
Hi James, once the boat is finished you'll have to obtain a Certificate of Measurement and then register the boat with the RYA to get a sail number allocated. I'm no expert on the subject as I'm in the US and haven't figured out yet how to do it here. For information on boat registration and obtaining sail numbers, take a look at this RYA page and also download the latest Merlin Rocket Class Rules. See Class Rule 18. You can also contact Committee members Dan Alsop for questions on Class Rules and Graham Williamson on measurements. I haven't decided on a name yet. I did promise to have it by the time I finish the deck, so I'll have the boat name in time for the next update. Good luck on your project!
16/07/2014 21:44:29 Robh3708
Looking great Julio, keep it up, you're getting there
18/07/2014 13:43:39 Julio Arana
Thank you, Rob. I used several photographs from Wicked to obtain the detail needed and get the work going. Cheers!
18/07/2014 14:56:29 Luna Rossa
Yes, you're doing a great job Julio and she's looking lovely.
Just a note to James and others embarking on a similar venture, regarding some of the nasty surprises I have encountered which are not documented in my boat building literature.
1. Check the thicknesses of your plywood with vernier calipers before or after purchase to ensure the thicknesses are uniform. For 6mm ordered I received half the batch which was 6.5 mm and the other half which was 7.2 mm. I didn't realize anything was wrong until I had finished the scarfing and couldn't get the level finish on the planks I was seeking. Yes, I had to redo some planks.
2. It probably doesn't apply if you are adopting the standard procedure advised by Keith for a plywood transom but if you are going for a solid (African) mahogany one when you get to the planing be careful of the humidity of the shop. On a table having one face resting on the table and the other open to the atmosphere you'll find the transom will warp and when you turn it over warp again and on and on. To avoid this take the wood to a warmer environment and let it stand with both faces to the atmosphere for a week. That way you reduce the warping and can plane the transom level. But proceed delicately.
3. Be careful when you are laying down the hog over the molds and to the bow and stern. Keith says there should be a slight S bend between stations 3 & 4, I believe - and it is slight. If your inner stem is too high you'll get the S between stations 1 and 2 and when you go to put the keel on it will look strange -like a banana. Of course this happened to me and I had to adjust the thickness of the hog, using a thin fillet to get the best curvature.
4. Careful with the epoxy mix and don't mix too much, a little at a time and thicken it up with colloidal silica until it is like margarine or slightly thicker in a plastic freezer bowl. If, like me, you mix too much everything will melt and you'll have a fire hazard with smoke pouring everywhere. Also, if its too thin then, when you come to put the garboards on, there is so much force that the epoxy won't hold and the garboards will spring off creating an awful mess and a nightmare to resolve, as happened to me. Clean up with sandpaper acetone & redo.
5. If you're a stickler for detail, you should bevel the inner stem and transom before laying the planks. This is tricky and requires a ton of patience but Keith should be able to give you the inner and outer profiles of each of these.
6. (you better start getting the beers in .:-)) You may have a whale of a time with the gains at the bow for all the planks. Keith suggests mating surfaces, the books use gains which are lipped insets into each plank at the bow to obtain the correct blending of the hull lines and maintain the beauty and grace for which Merlin Rockets are noted. I am a masochist by nature, and consequently took the hardest route with all this - cutting out two half gains for each plank. Think about two hours for each half gain measuring checking chiseling and planing, four hours alone for this for each plank, about 60 hours total, the sheerstrakes only have one each. However, in the final analysis this is probably stronger and guarantees more linearity in the blending at the bow.
7. And one final one. You need to be really careful when you lay the planks. the outer edge should be fair, ie a lovely gentle curve without any dips. If not, you need to support the plank in its correct position using anything to hand to get the correct geometry. The horrible positions are in the space towards the transom where the planks are inclined to dip and between stations 1 or 2 or 2 or 3 particularly for the garboard or broadstrake.
Anyway, I don't want to bore you with further details, just now at least, but just to say - be aware.
As I am now a fully qualified paid up member of the MROA again, I now feel justified in banging out my views in this space.
The boat ?? - She's coming on and now I'm about to start the gunwhales and I know that's another nightmare awaiting me just around the corner.
However - Sim Salabim
Good Sailing Everyone & Best Wishes
19/07/2014 12:18:56 Julio Arana
Thank you. These are great construction recommendations. I also read about what happened to your shelves and it reminded me to inspect mine as they are very close to the boat. Gunwhales can be fun to make... Wood knots and bends don't agree. Based on Keith's recommendation, I removed the knots from the stock and scarphed pieces to achieve the desired length. It was hard for me to find knot-free Western Red Cedar stock. Then, I (finally) focused on cutting one dimension per drawing section at time and got it going. When are you posting photographs of your boat? Would love to see the progress.
20/07/2014 06:50:16 Luna Rossa
At the moment I'm bogged down preparing a paper for the JPC, from 28th-30th July, over in your neck of the woods, well almost, Ohio. But once that's out of the way I'll get organised with some photos. Here's an image of the state of play in May.
Thanks for the info on the gunwhales. Actually, and remarkably, the Western Red Cedar I got over here was top quality and I already have the lengths, but my fear is that once I start bending all the fun starts !! I had thought of clamping a small section a day at a time to allow the wood to acclimatize to the curvature.
Good luck with your progress and once again, you're doing a great job and she's looking lovely.
20/07/2014 19:59:39 Julio Arana
Thank you for the photo. She's shaping up nicely! Your thoughts on clamping and flexing the gunwhales one section a day at a time will prove very helpful, especially around stations #5 and #6. I believe I started there and worked my way out in both directions. Those two stations have more 3-dimensional bend and torque than the others.
20/07/2014 21:46:46 Andrew Mills
Gents, your skills and dedication are awesome. I have spent a little time this afternoon making a small scarf joint for a repair for Heaven Sent (till the heavens opened!) and doing all the carpentry involved in actually building a boat boggles my mind.
However I have learnt what the words "dry run" mean.
21/07/2014 16:39:42 Gareth Griffiths NHRC
Tried to video the current state of play on a YouTube app
21/07/2014 18:53:20 Julio Arana
Andrew, thank you. Glad to hear you'are spending time on dry runs. It has helped me save time and money. Post a photo of your project.
Gareth, she looks fabulous. How many coats did you apply to achieve full opacity? What kind of paint volume did you require per coat for spraying?
21/07/2014 20:32:33 Gareth Griffiths NHRC
I am painting and fairing with Durepox Black.
I painted four coats with 50/50 thinners and mixed paint then used this as a fairing layer to get the hull smooth... The first three coats were sucked into the wood very fast.
After fairing we sprayed seven coats, gradually getting thicker. First two consumed maybe 900ml of paint the later coats double that if not more.
The colour was solid after the second coat.
I have just sprayed the centreboard today. I think I got eight coats on each coat was about 200ml.
At the end of last week I fitted the aluminium keel band and machined two triangular aluminium fairing joiners to hold down the centreboard slot gasket for and aft as well as joining the forward keel band to the two either side of the centreboard case and the aft too..
I then etch primed these with Mil-Spec to stop any unwanted oxidasation on the Aluminium.
Tomorrow I'll fit the centreboard, the pin screws through the keel planks, I will then fill the keelband, screw holes, and a few spots on the hull. Then knock it back flat and paint the top coats of three more black then three clear acrylic.
22/07/2014 07:29:23 Luna Rossa
Thank you for your kind comments. For my part I am no great expert but the books I have recommended in the past which have taught me how to do things are :
"How to build glued lapstrake wooden boats" by John Brooks and Ruth Ann Hill and
"Clinker Plywood Boatbuilding Manual" by Iain Oughtred
give all the descriptions and technical information you need. In particular the John Brooks text tells you all the steps to cut scarfs, gains bevels etc.
Regarding the scarfing for planks the scarf should be 8:1 minimum, so for 6mm ply the scarf length would be 48mm.
The reason why it is 8:1 minimum is that if it is less, 6:1, say (which would be sufficient for strength), is that when you go to curve the plank you will see a flat area in the scarf region, not the perfect curve I have alluded to in a previous text.
With 8:1 or more the forces of the epoxy joint are dissipated over a longer distance enabling a finer curve to be achieved over that rather stiff region.
I hope that explains things. - I made an angled jig having a plywood base and two hardwood (mahogany) rails set at the correct angle to do the scarfing - and just slide the jack plane delicately over the wood I am scarfing until I get the correct scarfed face. But all this is explained in the John Brooks text.