Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: My new G-nu  (Read 6766 times)

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
My new G-nu
« on: July 05, 2008, 02:56:51 pm »

Yes, it’s just a g-nother g-Springer! (with apologies to Flanders and Swan http://www.youtube.com/watch?v=OPgo6s1lBbw&feature=search_on_watch&search=flanders%20swan%20gnu). I just knew my new boat had to be "Gnu".

This is only my second boat – previous one was a Midwest Lobster Boat kit.

I built the hull before thinking about what I would put “on top”. Given that the design weight was to be something over 8 Lbs I started with some ¾” ply for the sides. Following the specified measurements, I made a template for the sides from a cornflakes package and transferred the outline to my wood. Putting two pieces together, I used a sabre saw to cut out the sides. The cut-offs were saved so that I had a matching curve for the skeg, which I would add later. I had a bit of luck in finding some off-cuts of discarded 1.5mm ply at the local lumber store – enough for deck and bottom.

It was a fairly simple thing to assemble the pieces square, using epoxy, and putting a small brace in each corner. The plastic sheet (old grocery bag) was used underneath to protect my work surface from drips and runs. I had read of the tendency of these boats to nose dive, so I provided for the bow to rise some small amount above the deck. Together with the knees, which I would place in line with the sides, this would provide something of a dam against the ingress of water over the bow.

The bow piece was cut at an angle approximating the curve of the hull. After assembly, it was time to give everything a good sanding whilst I could still run through the inside of the hull without having the bottom in the way.
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #1 on: July 05, 2008, 03:01:53 pm »

I cut the piece for the bottom slightly over-size for later sanding to conform to the hull. Putting on the bottom proved a bit more of a challenge than I had anticipated, partly because of the resistance of the material to the required amount of bending and partly because I found it difficult to get the clamps to hold the material round the concave curve towards the stern. No doubt there’s an easy solution to this problem, but I don’t know it!

The pictures show my first trials (when I was still working on the dining table – I am blessed with a remarkably tolerant wife!). I’m afraid I forgot to take pictures of my eventual assembly, but what I ended up doing was working in the opposite direction, working from the bow rather than the stern. Now in the basement I clamped the bow in my Workmate – it just seemed to fit snugly at the right angle, which was no more than good fortune. I then bent the bottom in stages.

The front part was easiest because I could clamp the pieces at the hull’s deepest point without any tendency for the clamp to slip. I then screwed the bottom to the hull, just for good measure. Screws were countersunk and later filled with plastic wood. When that had set, I moved on to the rear parts, relying on the screws to hold things in place before the clamps wanted to slip off the awkward curves.
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: My new G-nu
« Reply #2 on: July 05, 2008, 04:22:43 pm »

I had read of the tendency of these boats to nose dive, so I provided for the bow to rise some small amount above the deck. Together with the knees, which I would place in line with the sides, this would provide something of a dam against the ingress of water over the bow.

Welcome to the wonderful world of Springers!.

That looks like a VERY substantial build!... A Standard Springer, with a pair of 6v 4 - 5ah batteries comes out at about 8lb.. though some Springers have been known to get towards the 10lb mark without any adverse effect.

By the way, a 'dam' at the bow wont help stop any water pilling up and coming over the bow. Triming the boat to be slightly stern heavy seems to help more.

To get the bottom of the hull to conform to the curve easier, its an advantage to wet (the outside) of the ply and clamp it down before trying to glue it. After it has dried, its easier to curve (it already has a curve) to the shape of the sides.
Logged

chingdevil

  • Guest
Re: My new G-nu
« Reply #3 on: July 05, 2008, 04:41:02 pm »

Like Toes has said wet the outside to get the ply to curve. I do not clamp mine I use a power stapler to tack it into position, wait for the glue to dry the pull the staples and fill the holes. I have also nailed my hull on using panel pins, punched below the surface..


Brian
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #4 on: July 05, 2008, 06:38:50 pm »

Next I addressed choice of running gear and where it would fit to allow maximum clearance for an appropriate prop. At the same time, I knew I wanted the shaft to be as near horizontal to the deck as was possible because of those stories about nose diving – I didn’t want any up-thrust at the stern. Also to be considered was how far the shaft and prop could project from the hull and still leave clearance for the regulation 4 sq inch rudder (which would depend in turn on the dimensions I chose for the rudder). The rudder, of course, needed to sit within the vertical line of the transom.

Clearly, the shaft needed to sit low in the hull, so I decided on a geared system in which the shaft would be housed below the motor. I figured a rudder 2.25” x 1.75” would come near enough to the magic 4 to satisfy specifications. I would pivot it approximately 1/3 from the leading edge.

So now I knew approximately where the rudder post would have to penetrate the hull and how far the shaft could be allowed to protrude and yet leave room for the prop. This determined where the motor would need to go

I made a half scale drawing to see if this would all work. To be doubly sure, and overcome a little newbie fear, I did a full scale drawing of the running gear and then laid out the running gear on the side of the hull as a further check (approximate!).
Logged

chingdevil

  • Guest
Re: My new G-nu
« Reply #5 on: July 05, 2008, 06:44:28 pm »

Looks like we have a profesional Springer buider in our midst. ;D ;D ;D
Plans what are they?


Brian
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #6 on: July 05, 2008, 06:54:58 pm »

K-k-k-k-CHING!
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #7 on: July 05, 2008, 08:09:41 pm »

Agreed a real pro at work. O0  What theme for the top I wonder ? Nice work Kas, she`s going to be a tough old bug.....Springer for Footy games.
Logged
..well can you land on this?

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #8 on: July 05, 2008, 09:15:14 pm »

After all that, it was time to take courage and make some holes. Since the dimensions of the ply gave me the opportunity, I decided to drill the keel for the shaft, rather than make a sandwich of it. Then I drilled through this to puncture the hull. The acid test followed – would the shaft be level? If anything, it had even a slight rise from the motor towards the stern – even better than I had planned for!
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #9 on: July 05, 2008, 09:17:35 pm »

Then it was on to installing the rudder post, giving it some interior support. The knees are made in two pieces, glued together, with the inner piece extending substantially into the hull. The hull was soon encased in light weight fibre glass, and though she still felt a bit naked, she ventured towards the pond, but still without her running gear. A little later the Gnu acquired a coat of primer, and a deck and had her prop shaft fully installed, so one sunny day she dipped her toe in the pond.

 
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #10 on: July 05, 2008, 09:22:01 pm »

It was now but a skip and a jump to full respectability. It’s wonderful what a coat of paint can do for a girl, and then she can take a belly full of machinery and run around town showing off to everyone. “Look at my nice high coamings” she’ll say, and “See I can take more than that measley old 40 mm prop they gave me – then I’ll really kick over my traces!”

But I know behind my back it's another story, but at my age I turn a blind eye.

“Sorry to say my boyfriend took me out to the Expo before I was watertight", she said to someone. "It really ticked me off! He knew I wasn’t really ready but he was all in a rush and I shipped a load of water – but that’s OK, ‘cos I got a good coat of resin inside too. He was so sorry and he’s promised it won’t happen again.”

“But I’m really upset, ‘cos he keeps forgetting to take his camera to the pool. I’m really beginning to think he’s past it - I mean I must look really cool on the water in my Kenya colours, and he can’t remember. He’d better sharpen up next time we go out or he’ll be sorry! And another thing – I really hope he’s going to get me a new outfit for Christmas ‘cos I want to dress up like the other girls – cheapskate, but I know he loves me! Like someone said, it might be nice to have a theme party but he’s really got no imagination!”
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #11 on: July 06, 2008, 08:55:12 am »

Wow ! I`ll have a pint of what he`s having {-)   Nice job.
Logged
..well can you land on this?

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #12 on: July 06, 2008, 11:24:20 am »

So enough of that nonsense! There are one or two things I forgot to weave into my story. I don't have a scale to weigh the whole assemblage complete, but the parts (painted) came out at 8Lbs 9 ozs - near perfect, but no credit to me, merely fortuitous. So I have no ballast in the boat.

I rushed to meet the deadline for our annual steering competition, and so ran (first time in the water!) with the deck merely screwed on but not sealed and the batteries loose for trimming. You may imagine what happened, since the competition was in part a time trial. Put in the water, she sat just right with the batteries as far back as I had allowed for (again, fortuitous). But of course when I took off the power to maneovre round an obstacle, the batteries slid forward and she ran bow down, shipping water over the bow, so I headed fast for shore!

I suppose I really should acknowledge that though things may seem fortuitous to me, since I was not conscious of having an assuredly good end-product, it really is testimony to the skill of the designers that merely following their guidelines led to such satisfying results.

The batteries have now been stabilised and she runs slightly head up, which is what we want. She is very maneuverable (where DO the e and the o and the u fit?) in forward motion, but hates to go in reverse. This was very evident in the reversing sections of the course we had to run in the steering competition and has not improved since then.

So I have a question. Is reverse commonly uncontrollable, or is there some solution? I would really appreciate any tips on how to correct this one fault if anyone has suggestions to offer.

And a regret - at the moment I don't have anyone to play with! But I have one taker for a build next winter and I hope others will get bitten by the Springer bug. I'm sure they would if they could see the amazing work of some of the contributors around here as displayed, for instance, in the Rogues Gallery - you folks are a real inspiration - many thanks.

Meantime, thanks for the kind words - really undeserved because quite the contrary of being a master builder, I merely tried hard, but really I didn't know what the hxxx I was doing! I hope that my story will give some encouragement to others who hesitate - things really can work out even if you don't have any experience to fall back on! I learned a lot along the way and really appreciate the wealth of shared information in places like this - thanks again folks!

And if I can remember, I'll post a few snaps of her in the water later next week.
Logged

toesupwa

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 938
  • USA'd ex Brit
  • Location: Back in California, USA
Re: My new G-nu
« Reply #13 on: July 06, 2008, 03:27:17 pm »

So I have a question. Is reverse commonly uncontrollable, or is there some solution? I would really appreciate any tips on how to correct this one fault if anyone has suggestions to offer.


Reverse takes 'guesswork'... Yes, a standard Springer goes where it wants to in reverse, you have to make an educated guess as to where it will go. I've found you 'can' control it with some carefull use of the throttle finger combined with full rudder...  :D

The only way you will get it to properly do what you want is some 'flanking rudders' or a Kort.
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #14 on: July 06, 2008, 03:56:52 pm »

Beat me to it Toes, Kaskazi have a look at Towboat Joe`s site or RCGroups.com in "Dock Talk" under "Homemade Hulls" he is advising someone from SW London on how to fit flanking rudders but your Springer wont be eligible for Footy Games if fitted.  I know what it is like with nobody to play with !
Logged
..well can you land on this?

Mr Andy

  • Guest
Re: My new G-nu
« Reply #15 on: July 06, 2008, 09:59:00 pm »

And me, but mine shifts a lot of the wet stuff. :(

Andy. ;)
Logged

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #16 on: July 10, 2008, 10:50:42 am »

Not the sharpest pics you ever saw, but Gnu shows her paces
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #17 on: July 10, 2008, 11:19:49 am »

Nice, what you might call a "public debut"...where is that.   People walking on water too :angel:
Logged
..well can you land on this?

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #18 on: July 10, 2008, 12:25:59 pm »

It's in front of City Hall, Kitchener, Ontario - nice pool, but only 6" deep.
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #19 on: July 10, 2008, 12:30:32 pm »

CANADA :o and I thought I`d just nip down and have sail. You should have given us a clue, like a Maple Leaf ensign or a Mountie in the background !
Logged
..well can you land on this?

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #20 on: July 10, 2008, 12:51:40 pm »

Sorry about that!
Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #21 on: July 10, 2008, 01:11:52 pm »

 O0...and the Mounty >>:-(
Logged
..well can you land on this?

Kaskazi

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 59
  • Location: Waterloo, Ontario
Re: My new G-nu
« Reply #22 on: July 10, 2008, 04:21:35 pm »

Oh alright - since you insist, one last post. Keeping to the nautical, here's that iconic song - seems they also get their woman (except for Maud perhaps)
http://www.youtube.com/watch?v=2jPiWKodOZ4&feature=related

But beware of impostors!
http://www.youtube.com/watch?v=_47Xl4A98OU&feature=related


Logged

Arrow5

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,881
  • Location: Scottish Highlands
Re: My new G-nu
« Reply #23 on: July 10, 2008, 05:17:31 pm »

 O0Thank you Kas. {-) {-) {-) ..at least they were in a boat ::) .   I think the wardrobe dept got it wrong in the second clip though. LMAO {-) {-) {-)
Logged
..well can you land on this?
Pages: [1]   Go Up