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Thread: River Rat Navigator (Lower Hutt, NZ)

  1. #1
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    Default River Rat Navigator (Lower Hutt, NZ)

    I'm near the point of starting to build a Navigator, so thought I'd give the build thread/blog thing a try. I bought the plans a while ago, following some debating between Pathfinder and Navigator and some discussions here and elsewhere. I've been somewhat delayed in starting by house jobs - painting and fence building. The back of the house, sans paint:
    IMG_20170410_112758149.jpg

    It's looking better than that now. Thought I'd upload a photo though to see how it works.

    This evening I've been studying the plans again, and budgeting for some materials with my accountant, Pirate:
    IMG_20170921_211123531_HDR.jpg

    I've got as far as identifying some Macrocarpa for stringers, gunwhales etc. and for the rudder and centreboard from a family-owned mill and forest in Wanganui. I like dealing with businesses like that, particularly on a project like this which is an entirely recreational thing. I'll hopefully be picking that timber up next week, not from the mill but delivered locally. The ply will likely be Meranti which I can buy locally, though with some misgivings about the forests it's logged from. My ecological conscience probably wont stretch to sustainable Aussie Hoop Pine marine ply at $260/sheet...

  2. #2
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Welcome to the forum. Always good to see another Welsfordian.

    Kenny.
    "Oh my god, Triscuits are, like, the best." L.F Herreshoff, The Compleat Cruiser

  3. #3
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Yes, welcome. Glad to see you got the photo thing sorted. We love to see pictures!
    Looking forward to your build.

    Mike
    "near it, a small whale-boat, painted red and blue, the delight of the king's old age."

  4. #4
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Where are you getting the Meranti plywood from? I looked around Wellington a while ago and the poor quality led me back buying Ocuume.
    Otherwise, following with interest.

  5. #5
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Hi Slacko, I was planning to get the ply from City Timber, based only on some emails with them. I haven't seen their meranti. Last time I bought ply from them, for a repair job, they had pretty good marine glued Fijian Kauri ply so I was hoping they still had some decent quality stock.

    I'll have to see what they, and others, have. I'd rather buy locally so I can see the ply before I get it.

  6. #6
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    So, during the week I had a delivery of 4 litres of epoxy, and 1 litre hardener. This is own-brand stuff from a local fibreglass supplier, I also have leftover West from previous repairs so I'll make a comparison.

    Today's pick up was more fun - I had a load of 150x25 mm and 100x 50 macrocarpa to collect, which had been shipped to a local furniture maker, thrown on top of his larger order to save shipping. Some is clear, some has few knots so as I cut the stringers etc I'll have to pick and choose and scarf to make up the lengths. The idea is to get reasonable quality without gold-plating on this project, and I'll record the materials budget for those who are interested.

    Next step - I'll start cutting the 100x50s and make blanks for the rudder and centerboard. I'm planning to start with components, to put off occupying the whole garage a little longer.

  7. #7
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Just for the record, the super expensive Aussie hoop pine marine ply is also way too expensive even for an Aussie boat builder. Having said that, I have actually used some since a friend gave me a range of 'off cuts' left over from some jobs he'd worked on. It is definitely a very high quality product, and nice to use. Going back a few years (about 20 years actually) the imported marine ply commonly available was coming from Fiji and was of an outstanding quality... a different timber to the Aussie stuff, but otherwise of the same quality... wind the clock forward to about 10 or 12 years ago and the imported 'marine' ply was of a notably crap quality, less plys, and the core plys being quite a bit thicker than the face plys... what I didn't realise then was what imported so called marine ply would look like in 2017. The best material I can find now (excluding the too expensive Aussie option) in, for example, a 12mm sheet has three thick core plys with face plys so thin they can not be sanded at all, and in fact a few sheets in the last batch I received had been sanded by the manufacturer to the point that part of the face ply was missing. There are also sizable voids, and core plys containing big knots. I've shopped around a lot but the story is the same everywhere... apart from the Aussie stuff I don't think ply material worthy of the name 'marine' actually exists anymore. Take what you can get and make up for sus quality with a good layer of glass each side.

    On a happier note, I love the pic of your cat... looks so chilled out and content

  8. #8
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Bum. I'm an idiot. I glued up my centreboard blank last night, after a full weekend of social commitments - my mum was in town for an exhibition opening, and my ex-wife had a Sunday afternoon gathering for her upcoming birthday. I measured the epoxy by weight, but re-thinking it this morning I'm fairly sure that I've over-done the hardener. I'd measured the weight of equal volumes of hardener and resin to get their relative density to convert from 4:1 volume ratio, and I think I got the relative density upside-down when I worked out the weight ratio. So, way too much hardener.

    IF the squeeze-out looks and feels cured tonight - should I carry on? Or should I saw down the glue lines and glue it again... To be honest, that won't take long on the tablesaw and I have more timber to get the width back.

  9. #9
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Are you using the protective paints 4-1 epoxy from Petone?
    I've used quite a bit of it and am happy with the results, except the colour of the hardener makes clearcoating not an option.
    I found this out the hard way with my cedar dinghy that I'm building.
    I dispense it by volume by using the Spare West pumps that I have. The hardener pump fails on these sets and I had no success cleaning them as people here suggest, so I had 2 resin pumps. I just give 4 pumps of the resin and 1 pump of the hardener.
    I was getting Okuume from Moxon timber in Seaview, but they got bought and closed to the public.
    Nichols and Maher have a warehouse in Seaview that can supply ply as well.
    I've not bought ply from City Timber, but am getting exotic timber through them now.

    The centreboard is a loaded component, so you might always end up thinking about the strength of it if you did get the mix wrong.
    If it's not a biggie to rip the gluelines and rebuild, you will probably be happier in the long run.

  10. #10
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Quote Originally Posted by Slacko View Post
    Are you using the protective paints 4-1 epoxy from Petone?
    No, NZfibreglass own brand 4:1 resin. Yes, it's yellow but I knew it would be.

    The centreboard is a loaded component, so you might always end up thinking about the strength of it if you did get the mix wrong.
    If it's not a biggie to rip the gluelines and rebuild, you will probably be happier in the long run.
    Yeah I probably will redo it. Chances are I'll want to stand on it at some point...

  11. #11
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Ok, not seen that one. The stuff I've got is red.
    I bought some totally clear stuff the surfboard guys use at 2-1 ratio from a Kiwi online store.
    It is apparently UV resistant (not going to test that, but nice to have under the varnish).
    They also do an ecopoxy that has less nastiness included, which your first post would indicate you would like.

  12. #12
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    I hadn't realised that surfboard guys use epoxy. I'll have a look for that one. Trademe?
    There is nothing quite as permanent as a good temporary repair.

  13. #13
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    I got it from "Fibreglassshop.co.nz".
    I am just a happy customer, no affiliation.
    Price excellent and next day delivery mostly.

  14. #14
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Thanks for that, I'll check them out.
    There is nothing quite as permanent as a good temporary repair.

  15. #15
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    If you havent got your ply yet I'd go with good quality gaboon/occume. The reason is light weight, hoop pine is dense and heavy, meranti is a word describing virtually any brown tropical hardwood and quality/weight varies. The biggest mistake is overbuilding or building weight in unnecessarily and the lighter you make your boat the easier it is to handle and the better it performs all round. For the dimensional timber its hard to go past treated Kaihikatea for weight and strength. In terms of wear and abrasion resistance, use strakes with UNMW or brass strips in the appropriate places. I wouldnt bother glassing the exterior but if youre going to do a stringerless build (looks great and easy to clean) then you'll need to tape the joints
    whatever rocks your boat

  16. #16
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    I haven't got ply yet. I was thinking of Meranti for durabilty but certainly understand the argument for lighter timber.

    hadn't thought of a stringerless build, as I thought that I needed the stringers to give the light ply sufficient stiffness - particularly if I do the top strakes in 4 mm as JW advises in the plans is allowed. To be honest I'm planning to stick very closely to the construction in the plans to make sure I don't cock it up.

    I'm definitely onboard with the light-weight philosophy though, this will be a simple and light boat, no teak gratings or hardwood veneers.

  17. #17
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    A few months later - slow progress but I’m moving foreward. Today I put some more time into shaping the foil part of the centreboard - I’d used my new router and a MDF jig to cut close to the final foil shape, and today planed it smooth and to the line I’d marked on the bottom of the board. Will add some pics later from the PC, I’m working from an iPhone and they keep going in upside down...

    Last weekend, I sailed a Navigator for the first time, courtesy of Richard Schmidt and friends who had a Messabout over at Onepoto (half an hour from my place). I’ll add a photo or two of that too.
    Attached Images Attached Images

  18. #18
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Quote Originally Posted by Small boats rock View Post
    Just for the record, the super expensive Aussie hoop pine marine ply is also way too expensive even for an Aussie boat builder. Having said that, I have actually used some since a friend gave me a range of 'off cuts' left over from some jobs he'd worked on. It is definitely a very high quality product, and nice to use. Going back a few years (about 20 years actually) the imported marine ply commonly available was coming from Fiji and was of an outstanding quality... a different timber to the Aussie stuff, but otherwise of the same quality... wind the clock forward to about 10 or 12 years ago and the imported 'marine' ply was of a notably crap quality, less plys, and the core plys being quite a bit thicker than the face plys... what I didn't realise then was what imported so called marine ply would look like in 2017. The best material I can find now (excluding the too expensive Aussie option) in, for example, a 12mm sheet has three thick core plys with face plys so thin they can not be sanded at all, and in fact a few sheets in the last batch I received had been sanded by the manufacturer to the point that part of the face ply was missing. There are also sizable voids, and core plys containing big knots. I've shopped around a lot but the story is the same everywhere... apart from the Aussie stuff I don't think ply material worthy of the name 'marine' actually exists anymore. Take what you can get and make up for sus quality with a good layer of glass each side.

    On a happier note, I love the pic of your cat... looks so chilled out and content
    As Paul said, hoop ply is really heavy! Nice but heavy. You could contact Andrew Denman at Denman Marine in Tasmania. He imports gabon, I think. It wouldn't be any cheaper than hoop though, I'd guess.

    Rick
    Last edited by RFNK; 01-27-2018 at 03:22 AM.

  19. #19
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    I used Aussie hoop pine for the bulkheads, bottom and planks of my Scamp build, and used cheaper imported ply for the soles. I wish I'd used hoop pine for the lot now. Mind you, after 5 1/2 years, I'm still only 'nearly finished'
    When I first joined WBF they made me write a book to prove I was a real yachty. I was so gullible.
    Paperback E-book

  20. #20
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Inspiration - a couple of pics from the weekend before last. The Navigator in the pictures, I'd sat in on its trailer a year or so ago, when I was deciding which plans to buy. Richard kindly let me sail it, and I was very impressed and happy that it's the boat I want - which is good, as I've started building.

    I bought some lead today to weight my centreboard, conveniently in two 30mm thick lumps so I can just cut the appropriate hole in the board and glue it in.

    IMG_0524.jpgIMG_0532.jpg

  21. #21
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Quote Originally Posted by OliverBendix View Post
    I haven't got ply yet. I was thinking of Meranti for durabilty but certainly understand the argument for lighter timber.

    hadn't thought of a stringerless build, as I thought that I needed the stringers to give the light ply sufficient stiffness - particularly if I do the top strakes in 4 mm as JW advises in the plans is allowed. To be honest I'm planning to stick very closely to the construction in the plans to make sure I don't cock it up.

    I'm definitely onboard with the light-weight philosophy though, this will be a simple and light boat, no teak gratings or hardwood veneers.
    The 4mm ply is only used to make the curves in the coamings easier to form, you can do that in 6mm with a bit of soaking in hot water though.
    On plywood, I'm getting pretty nice plywood from Plytech in Auckland, they'll ship it if you need to do that. http://www.plytech.co.nz/meranti-bs1088

    John Welsford
    An expert is but a beginner with experience.

  22. #22
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Slow progress continues - after evicting a collection of second hand stuff from the garage I’ve been back at centreboard shaping, including chopping a hole for the lead.A4B348DD-AF85-4D51-A61F-A9EB6DA0C8DE.jpg

  23. #23
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    And after evicting yet more second hand stuff, I've glued the lead into the centreboard:
    IMG_0843.jpg

    and also glued up a rudder blade blank:

    IMG_0842.jpg

    The rudder blank staves were courtesy of my new cheap planer/thicknesser, a great labour saving machine compared to cutting the centreboard staves using a hand-held electric planer. I have all of the stringers and other solid wood material in rough-sawn 150x25s and looking at that stack made me feel tired so I splashed out on the thicknesser, and a cheap mitre-saw stand with rollers to mount it on. I didn't get a picture of the setup but it's a good one-man operation.

    I'm thinking of glassing the whole centreboard for strength and rock resistance and wouldn't mind some advice - glass both sides at once, and all the way to the square top? One side at a time? I haven't done a lot of fibreglass work, just repairs after replacing rotten deck and coaming sections on a trailer sailer and that process required plenty of filling and fairing.
    Last edited by OliverBendix; 04-08-2018 at 08:30 PM.

  24. #24
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    John specified 10mm hardwood dowels to keep the pivot bolt and uphaul from splitting the centreboard. As most of the dowel available here is pine and as weak as celery I used a bit of fibreglass rod for dowels, scavenged from the detritus in a colleagues office. A little splintery to work with but strong, so I may use it again.

  25. #25
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    I've been sanding away at the centreboard, in preparation for glassing it. I've drilled a 25 mm hole for the pivot, filled it with epoxy and microfibres, and need to re-drill at 20mm leaving a thin epoxy ring. What's the right drill bit to bore cleanly through epoxy? A 20 mm Forstner bit?

    I also laid out the rudder blade on the blank but am not totally happy with it so may re-draw it. The plan has a protruding eye for a lifting line, as you can see in my layout. I'm considering bringing the trailing edge right up to the eye, rather than having a cut-out which seems an invitation to split the top of the eye off. What do you think?

    IMG_0854.jpg

    I've also had a kind offer of some meranti ply at a very good price, bought by a colleague who's changed his project to cedar strip construction. So my boat will be meranti. As I'll get to laying out bulkheads and other parts soon, I have a couple of questions. How do most people arrange parts on a sheet of ply to cut out? Layout directly on the ply, or make patterns to arrange?

    I'm enjoying the occasional hour at this, usually between 9 and 10 at night as family and work commitments allow. I'd love a few uninterrupted days work, but slow progress is better than none and I'm learning the whole way.

  26. #26
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    What's the right drill bit to bore cleanly through epoxy?
    Any drill. It's soft plastic. I'd focus more on making sure the hole is square to the board.

    This could start some discussion, but I prefer the pivot hole to be a deliberately loose fit, so that the board can flop left and right a bit. This way the stresses applied to the board when sailing are transferred to the sides of the case, not through the pin.
    -Dave

  27. #27
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Thanks Woxbox. Making the hole square to the board is not too big a problem, I'll do it in the drill press and can support the end of the board on the bench with props to get it level. What do you reckon about using a 20mm pultruded fibreglass rod as a pivot pin? The plan calls for a 20mm OD stainless tube, but I have a piece of rod I found cleaning up at work. To be honest I think I'd break the case or board before breaking the rod.

  28. #28
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    1) I did the same thing on the rudder - I extended the leading edge up around the hole.

    2) I drew the plans full sized on paper, then poked holes to transfer to ply. It's on my thread here.

    If I were to do it again I would have made the bulkheads out of one piece. I found it difficult to glue all the pieces into the right shape.
    "Oh my god, Triscuits are, like, the best." L.F Herreshoff, The Compleat Cruiser

  29. #29
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    Default Re: River Rat Navigator (Lower Hutt, NZ)

    Last week I picked up my 6mm meranti ply from a friend, and had a look at his project - a sailing dinghy, cedar stripped bottom up to a hard chime and the ply sides. I still need my 9mm ply but seeing the stack of sheets against the wall of the garage is nice.

    Progress today, after some busy weeks and weekends lately kept me away. I shaped and sanded my rudder blade and have coated one side with epoxy, thinking I may finish it bright. It’s not perfect but will look ok from the next boat. I thicknessed and glued together a couple of boards for the rudder cheeks, the two together will give me enough width to nest the pieces head to tail

    DB546C75-319C-4844-A397-AAD2C7AC7227.jpg

    And i covered the centreboard in fibreglass and epoxy. The plans say this is optional but as I enjoy sailing up to the beach things tend to go bump.B15987A8-6B1A-4D24-BD71-668315E3D0FC.jpg

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