surfdabbler

Hi smoofty, my keel bulb is almost exactly 1kg, on a 1:25 scale boat. I pre-calculated my weight based on the cross-section area and density of lead. I forget the actual formula at the moment. The actual weight of the bulb was really close to the calculated value. I'm going to scale the weight down to about 700g - the keel on these designs is made for a non-canting keel, so it's longer and heavier than a canting keel needs to be, and much longer and heavier than scale.

The displacement of the boat is the total weight of the boat, including keel weight. You should design your completed boat to equal this figure (aim for less - you can always add ballast if you need to. I also think the displacement weight is overstated, due to the heavier non-canting keel. The lighter you can make it, the better.

@ simpros1 - pics to come when I update my blog.

surfdabbler

Update to add... My 1:25 scale was rated at 1.5kg displacement, so the Keel bulb is roughly two thirds of the total displacement in the original design.

Formula for bulb weight (assuming roughly circular frontal section) is calculated from the side cross-section area...

Weight = area * area * 3.14 * density / bulb_length

where the density of lead = 11.34 gm/cm3

so, measure the area and length in cm, and the weight will come out in gms.

simpros1

My Feedback: (16)

Hey Guys!

Well I plotted out the new hull design from claudio's drawings and after seeing the dramatic difference in hull pattern
I contacted claudio to see about input from the guys using this design and to find out the builders have not completed
one yet[sm=confused.gif] So if I do it I maybe the first. The way I look at it they have spent Millions on designing the real
boat so that's a boost of confidence and than I think about a saying from dennis deprois who built over 50 boats and has walrus sails
tells me scale dont sail. check out the pictures and feel free to input?

I'm sure I will loose sleep tonight dreaming about it...lol

canno1797

Hey Boys,
I have got some more work done on the new hull. The first pic is the deck just after I finished glassing it and trimming it up. the second is a close up of the carbon weave only because I like the look of it, the last one is the new deck sitting in place. The next thing I hope to get done is to glue the deck on and install the keel box. Still thinking about the cockpit layout and the right place to install the winch.

Simpros,
the second line drawing looks like one of the early hulls that claudio did, can't remember the teams name but to me it is not what I would call a nice hull shape buts thats just me. Any more movement on the Oricale data files

canno1797

Got some time this week to do some more work on the hull. After cleaning up the shape of the deck it was time to glue in the under deck hard points for the jib mount. As you can see it just of 12 mm squ bit of spruce witch will take the screws for the jib track. I have also added in some more carbon for the keel box to sit on and also the rudder.

I glued the deck to the timber rail with 12 epoxy so I have enough time to push it all into place and now that it is set she is not coming off. Next was the keel box its self, as you can see in the pic I will be useing my 10 rater keel for this boat. It is a lot longer than keel shown on the plans even after you take into account the enlargement out to 1.5m so she should be pretty stiff. The the keel box is made up of 3mm balsa with carbon on both sides and a timber spacer front and back to make the room for the keel head to bolt up to. Again I have put the 12 hour epoxy to good use and after it has dried I will give it some more carbon all the way around just in case it wants to flex. After all of this has dried I wll be sanding it up and glue/glassing it in place. The next job will be filling and fairing the outside of the hull.

canno1797

I forgot to put in a more clear pic of the keel box, you can see the hole for the keel bolt to come through later on. In the last pic the epoxy is just about to be placed on the timber to glue the other bit of carbon down.

simpros1

My Feedback: (16)

Hey Smoofty!

Looking good and looks like alot of work but it sure worth it when it all starts comming together.
How long is you hull? How long is the fin? how much dose the fin and bulb weight? I will put up
some pictures of my 2 meter plug later this weekend and go over a couple of things with you.
Did you purchaes a RMG winch for this boat?

canno1797

Hey Simpros1,
Happy Easter to you and I hope you are having a long weekend like me . Ok the hull is 1.5m long the fin is 600mm from the bottom of the keel bulb to the underside of the hull. The bulb is 3.75kg, you may think that it is a bit over built but like I said before the large riggs push the hull to its limits when you sail them in about 15 - 20 knots and there is no ribs in the boat and the mast is steped at the bottom of the keel box so all the load is going into one point.

I can't wait to see your 2m plug should be nice. I met a bloke yesterday at my local yacht club and he was telling me about a 2m maxi yacht that he built and he posted a build log on his club webb site, here is the address not a bad job. http://www.cnlsc.org.au/ . I just checked the the link and it did not go straight to the right page. when you get to the home page go to twinbeach modollers then to the AU class link then click on Projects. Yes I did get a new RMG winch and it works very well with my new 2.4 GH TX

Till next time have a good weekend.

RCSailboatGuide

Wow, not bad or more to the point very nice.
Keep it up for the Kiwi's [8D]

simpros1

My Feedback: (16)

Ok here we go! I took a pick of me holding the 2M boat and I have to say I dont like putting my mug on the net but it's the only way I can show the size of the boat. I must have 50 feet of balsa and 10 pounds of bondo on this plug so far and note the hands I'm sure all you builders have looked like this before. I will keep sanding away and havee some more pics up soon

canno1797

Hey John,
Your like me a great head for Radio . She is nice and big what design was it again ?. I'm just about to glue and glass the keel box in this week so that should keep me going.

canno1797

John,
did you get my PM ????

simpros1

My Feedback: (16)

This is the Claudio 1/10 scale Alinghi AC 10 plans he gave to me in autocad format so I could convert them to our 1/12 scale
AC Class. I was not sure about the luna Rosa with such a flat bottom hull and the the Alinghi 64 that you mentioned that you did not like so this hull seem to be right in the middle of the 3. I sent an email for the volvo plans they never sent them to me??? And
once again what plans are you using?

canno1797

Hey mate,
I'm using the Vela RC Alinghi plan that I enlarged out to 1.5m as I liked the bottom curve better than the other designers Alinghi. As for the Volvo plan if you can give me email address other than the comcast one I will send them again.

Till next time.

canno1797

I have managed to move along a bit with the boat building this week. I finished off the keel box and mast tube and as you can see in the pics I have a bit of timber running on each side of the keel box and giving the mast base a good strong fixing point. I have also installed three carbon/balsa frames to mount the cockpit deck onto but I'm still trying to work out the best way to mount the sail winch. Today I started making the carbon mounts for the rudder post and rudder servo, should have some pics of that installation soon.

larrykin

Smoofty37,

that guy you met with the Nicorette AU Class boat. Small world. I have a boat from the same plug .
Here's a link to the build log photos -

[link=http://photobucket.com/AU_Class_Build_Pics]AU_Class_Build[/link]

and here she is sailing 3rd time out -

[youtube]http://www.youtube.com/watch?v=pmql1Rw8VAE[/youtube]

Larry L.

canno1797

Hey Larrykin,
Yes very nice, I checked out the build and he has gone to a lot of detail inside the hull. I don't suppose there is any chance of getting hold of a hull ?.

Anyway back to this job. I have installed the rudder post ( forgot to take a photo ) and rudder servo ( again forgot to take a photo ) and glued the cockpit deck to the cross frames and now just about to build the side walls for the cockpit. I had a bit of a stuff up and the front floor is not dead straight but after a bit of paint you should not really see it to much. I have also cut out the accsess hatches for the rudder and servo just need to do the main accsess hatch up front for the RX and sail winch.

I have not glassed the cockpit deck with carbon as some TX's don't like going through all carbon hulls. here are some pic's of the progress.

v6goose

Hey guys...

Just wanted to say Great job!

I'm an aircraft guy, but more importantly, a Kiwi living in Canada who loves the TT ETNZ but had been daydreaming how to scale it up. There was nothing around when I first looked but now you all are involved in it... excellent!

I have to admit its far more complex than I imagined, but hopefully I can glean lots of good info and solutions from watching you.

Cheers!

Goose

larrykin

Smoofty - I sent you an email re getting hold of an AU Class hull. Sorry took so long; my computer has been off line i.e. attacked by windows..... He also builds regulation A Class boats.

Guy who built mine collaborated with the guy you met; Stan. They spent years and lots of cash to make the Nicorette Model. It sails well. Stan's boat has ~16 servos but; because it cost so much he's to scared to sail it now. Just brings it out to show people at the place where I sail. Lake Chipping Norton, in Warwick Farm.

Larry L.

canno1797

Thanks for the info Larry,
I will investigate it this week. Ihope it I can get one at a good price and race it against my Volvo 70 when Iget around to building it. As for the NZ 12 I have not had much time to work on it of late ( I have been sailing my full size skiff ), I have glassed the back side of the cockpitwalls ready for glue. When I have all the parts of the cockpit set up I will place some light glass over the lot to lock it in place.

Simpros1, You have been a bit of a no show for a while whats going on with your big boat ?????.

till next time .

canno1797

Hey Boys,
Well after a couple of months of testing out my new skiff its back to building the NZ12. I have not got that much done yet only installed the sail winch and cut out the front access hatch on the fore deck, as well as adding a mount for a block down the back of the cockpit that will be used for the sheeting system. I gave the hull a sand in readiness for the spray filler and paint and the hull lines of the bow have come not to bad. Any way its fathers day in the morning so I should have some time to work on it.

surfdabbler

Hey Smoofty, Good to hear that you are still on it. I'd hate to think I was winning our race by forfeit. Don't worry, I still have months to go on my boat, so no rush. Your's is looking nice - I love the CF look. It will be a shame when you have to cover it with filler and paint.

Yachty_nut

Gidday there Guys, long time watcher, first time blogger. anyway i have been watching your build with much anticipation and have since downloaded all the plans from the Italian Website, had them all printed 1:1 and done the bulkhead shadows, Finished the hull, done a Mould from the Hull and now just finishing the mould with some fine wet and dry. but i have been on here just about every day looking to see if you had added anything. anyway enough about me! you boat is looking great, a shame you will have to paint it though the carbon look is great.

canno1797

Hi Boys,
Thanks for the support as I have been away from the boat for a bit. I have just been doing a bit of filling in around the stern with some light body filler ( the pink stuff ) and a bit of sanding. You can see in the pics the little post that has the sail winch block mount to it, I wanted to do something a bit different with the winch line this time so I will be running it down the back of the boat instead of the normal front like most of the RC race boat that I have seen. Since the start of this build I have sold off my first ETNZ boat so I will now have to build a new keel [:@] . This will put me more behind Surfbadler and his ICE VO VO .

As for the painting I'm not looking that forward to it after the time it took me to get the first one right but you get that.

Hey Yachty nut, I will be over in Auckland on Sunday for a couple of weeks and I will be going straight to the ENTZ HQ to pick up some sailing gear and have a look at the TP52, I might see you there.

Yachty_nut

Gidday there, i am always down at the viaduct most days, the partner works close to it. i would like to catch up, that would be great.