Build complete

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Best wishes and happy sailing, Bryn Heveldt.

Build complete

Joined: April 20th, 2014, 9:00 am

January 26th, 2015, 7:24 pm #1

Hi,
I started building a 750 about a year ago for my son. Last night I rigged it all up and she's ready to sail.

It's been a long but rewarding build, I've enjoyed it immensely other than a few hiccups.
I initially went with balsa and resin for the deck but had a paint nightmare – bought a particular brand of paint from Repco and gave it about 4-5 coats but it never dried properly. Left a thick skin that would move under your fingers and leave fingerprint marks, and was able to be dragged right off with a bit of pressure. So I had to scrape the sticky mess off and sand it right back and start again.
Second time around I went with a laser cut ply deck which I bought from Ponoko.com along with laser cut acrylic hatches and covers. They're held on with rare earth magnets (inspired by someone else on this forum, thanks!).

For rigging and spars I bought main and jib boom kits for the Dragonforce RG65 which fit and work very well. I also got a bit of 6mm carbon fibre for the mast. All other bits and pieces I bought of various model yacht supply websites. Sails are mylar.

Son can't wait to get her on the water.









Cheers.
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Joined: May 27th, 2014, 6:58 am

January 27th, 2015, 9:26 am #2

Well she looks the part..very nice indeed... you and your son have done a great job on her...
Bugger about the paint ...Life I guess.
I am keen to see how your hatches work out ..do they have any soft seal or just a neat fit?

When is the big day planned for? Must be hard to wait, I can see the water in the background.
Remember the photos and the champagne is for the boat not the captain and first mate... ;) ;)

All the best

Russell
Maker Of Things
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Joined: April 20th, 2014, 9:00 am

January 27th, 2015, 6:44 pm #3

Maiden voyage was held last night at the kid's school pool.
Unfortunately, after weeks of fairly brisk wind, we were becalmed.

Got a couple of gusts but not enough to satisfy the captain so we'll take her for another trial run in the pool before heading to the lake.

The hatches are a neat fit but pretty clearly not completely watertight, so I laid some self adhesive foam door seal around the holes (the laser cut hatch holes in the plywood are about 10mm wider than the holes in the balsa sub-deck). The foam stuff is a bit thick though (about 3mm) and it has affected how much the hatches stick up and how well the magnets suck them in. The magnets are very strong but not strong enough to compress the foam as much as I would have liked.

I'm not sure at this stage which is better, the foam making the seal less tight, or no foam with a neat-but-not-watertight fit.

Will report back when the wind gets up and it gets some water over the gunwhales.

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Joined: May 27th, 2014, 6:58 am

January 29th, 2015, 8:27 am #4

A thought for your hatches and the foam
If you cut the foam into a narrower strip say a square profile this will decrease the amount of foam to compress but still give it a seal.
Let us know how you get on, as I am still interested in this type of hatch.

Russell
Maker Of Things
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Joined: April 20th, 2014, 9:00 am

January 29th, 2015, 8:33 pm #5

I did cut the foam strip down to 2/3 but you're absolutely right, if I cut it down even more that will significantly reduce the compression resistance. Really good idea, thanks Russell!

We went for a sail the day after in the school pool, with more wind. Boat is a real rocket ship in a good gust and handles beautifully.
It still wasn't blowing really hard but we got a bit of water over the side and the hatches held the water out well. I'm still nervous though so will cut the foam down even more and see if the hatches can stick right down.

Cheers!
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Joined: April 20th, 2014, 9:00 am

February 1st, 2015, 9:50 pm #6

Cut down the foam as small as I could (whilst still leaving enough self adhesive strip to stick) and it's still not ideal, not grabbing hard enough.

We took her for another run on the school pool and it went pretty well until some swimmers turned up. So we had to leave but my son hadn't had enough and asked if we could just take it to the lake.

It was blowing a bit but I sent her out not too far and sailed her back again. So nervous!

Did a couple of laps not too far out and checked the hatches for seal. They had leaked a bit so I dried up the inside and then removed the seal tape completely just to satisfy my curiosity. Sailed her out again. Checked. More water. Argh!
I dried her off again and gave the controls to the boy, he did really well sailing her out, letting some sheet out when she went crazy in a gust, coming about and sailing her right back to where we were standing. But with more water inside we called it a day.

So exhilarating, she got right over and rocketed along, but got a bit bow down as well — probably a touch too much wind. Might have to look into a B rig.

I have to get a better seal on these hatches, makes me too nervous to sail. Laser cut is good but just not tight enough to be effective. Foam under means magnets don't grab enough to seal properly.
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Joined: May 27th, 2014, 6:58 am

February 3rd, 2015, 9:37 pm #7

I am just thinking about the hatch on my new build and have no idea of what size magnet are used.
What are you using and do you think there enough?

Russell
Maker Of Things
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Joined: April 20th, 2014, 9:00 am

February 5th, 2015, 3:45 am #8

The ones I used are 5mm diameter and 1mm thick.
They're neodymium so are easily strong enough to hold down the covers very securely, but not enough to compress the foam weather strip enough so that its watertight. Still thinking through a solution for that.
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Joined: September 6th, 2012, 9:19 am

February 5th, 2015, 7:55 pm #9

On my 750 I have removed the hatches and use deck patches made from self adhesive plastic sheet.
To prevent having to peel the front patch off to change the batteries each time, I have fitted the top of a plastic container with a screw on cap into the deck, which is big enough for the battery box to fit through.
This, coupled with a raised sheeting post so there are no open holes at deck level mean the insides remain dry in all conditions.
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Joined: October 28th, 2012, 11:48 am

February 6th, 2015, 9:46 am #10

I like the idea of a screw on cap as I feel sure that most people have experienced hatch problems. I also tried magnets but failed dismally. I have resorted to holding mine down with masking tape. Not very pretty but very effective and easy to remove for access to the battery pack.
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Joined: May 27th, 2014, 6:58 am

February 8th, 2015, 12:43 am #11

Yes hatches are a pain,,,I have been using a clear thin plastic and pvc taping it around the edges. On the front hatch having a hole that I can turn the power on and off with a small strip of tape to seal it up, saves taking the whole hatch of and on.
Like to see photo of the screw cap method ...hint...

Russell
Maker Of Things
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Joined: September 6th, 2012, 9:19 am

February 8th, 2015, 3:50 pm #12

Some pics of the screw top cover. This one is made from a vitamin supplement bottle. I just cut off the top and glued it into the deck.
The battery box shown is for AAA cells but an AA battery box will just fit with a little bit of shaving on the corners. I find the AAAs are adequate and are much lighter.
If you were building from scratch you could probably modify the interior to get the cap on the centre line if you wanted, but I think it looks OK where it is.
IMG_1424.JPG
IMG_1421.JPG
IMG_1417.JPG
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