Casting the bulb

[Chad]

Click his name in one of his earlier posts, and use the send message function...

...or wait for him to see your post and reply

[Marino]

Chad, Kiwi22 called me and we will be helping each other.

[Marino]

The beaver tail bulb mould has been given a plane ticket and is taking an international flight over seas. So if anyone wants it next, you'll have to contact Stealth.

[Chad]

That's awesome! Stoked its being used, and getting some miles.

[noemar]

I THINK WE ALL OWE A BIG THANK YOU TO CHAD FOR DESIGNING AND CONSTRUCTING THE BULB MOLD FOR ALL TO USE.

[admin]

I would be in agreement with that. Major props to Chad. And mine doesn't even have a beaver.

[Chad]

Awe shucks
...you can "thank" me by getting busy with those builds, and getting out on the water soon!!!!!



(no beave on my bulb either, Tim. I do have a mold for it though, in case mine should require replacement, for whatever reason...)

[Marino]

I raise my glass of kool-aid to chad for what he has given to us.
To the ones building, don't forget to place pictures on the forum.
What am i saying. I better get cracking on my i550, now that the weather is improving.

[ryderp]

Thanks are definitely in order. Here is a picture of my beaver tail on installation day (of the keel foil in the boat):

BeaverTail.jpg

Phil

[jray]

Very nice job!! Splash time close??

[Chad]

image.jpg

Do we have rules against this? I think every i550 needs 7 foils!

[Kevin]

Well, for starters, the rudder has to be transom mounted doesn't it?

[Chad]

Rats! Back to the drawing board!

(pic above is Wild Oats XI, with its S-H mods. Imagine sailing that thing someplace with kelp...)

[chuckand]

Chad,

I just received i550 plans (Hull #525) and am exploring things I can get rolling with before filling my shop with plywood. I've got access to 3-axis machinery and would like to start playing with the Rudder/keel/bulb. Do you have a model that you would share for the bulb that's being passed around? I'd like to carve a plug.

Thanks!

Chuck (in Aaaala Baaama)

[Chad]

Hi Chuck,
I have a kludgy 3d model of the bulb, but my software isn't geared toward boat stuff and doesn't produce the sweetest shapes once I go outside of its comfort zone. I do have all the profiles in cad form, if your software can do a better job assembling them into a solid...
-if interested pm me with your contact info and I'll be happy to send you what I have.

[chuckand]

Thanks Chad! That outta get me going!

I'll post what I do with it....

Chuck (in Aaaala Baaama)

[lohwaikin]

Hi Guys,
I am now moving on to machining the bulb for mating with the keel foil.
Is there written anywhere on this forum the position of the foil on the bulb?
Or can I still follow the dimensions for bolt-holes as per default plan?

Basically my bulb casting went rather awry.
I was at work went the battery recycler poured the bulb.
They told me the mould (made of Portland cement) started cracking midway thru' the pour.
And the result is a rather extra-terrestrial-looking piece of antimony-lead (straight from the battery plates).

2013-11-09-13 (Forum).jpg

2013-11-09-15 (Forum).jpg

I spent quite some nights chipping away at the embedded cement, and surforming the rough faces.

2013-12-22-2 (Forum).jpg

It's kind of looking like a bulb now, but I need to mate it up with the foil first, before commencing on some heavy puttying.
To my horror the main sprue on the starboard side turned out to be so "aggregated" with cement that it dropped off during chiselling and revealed a crater!
I do hope the boat will not list to port because of this...

Cheers,
Loh.

[micah202]

...looking good Loh!...I think that's as good as the pour's get,,nobody's hit -perfect- yet,as far as I know.

..the weight's good?

...in the past I've done keel-fairing with a power planer---all fun until someone gets hit with one of the many bullets shooting across the shop!
........get's the job done -fast-,,but don't forget to put a new power-planer on th'shopping list

[jray]

Hi Guys,
I am now moving on to machining the bulb for mating with the keel foil.
Is there written anywhere on this forum the position of the foil on the bulb?
Or can I still follow the dimensions for bolt-holes as per default plan?

What I did is place the thickest part of the foil at the center balance point of the bulb which should be around 387mm back from the nose. It has been working fine for me. There may be other ideas on this.

[ryderp]

Loh,

The bulb looks good. I had some gaps in my bulb. I melted a bit of lead and just poured it into the largest one. The smaller ones were filled with fairing compound.

Phil

[Tim Ford]

Really glad you asked this Loh, as my pour-date is rapidly approaching. Now I know where to place my foils plugs....thanks for that number Jray!

[lohwaikin]

The bulb weighs 80kg (176 lb), or at least that's what I've been charged on the receipt...

I've been figuring out how to machine a foil profile about 1/2" deep onto the top of the bulb, so that I can step on my keel foil to minimize the likelihood of timber splitting off while the boat is heeling off on a reach...

Without lugging the bulb off to some machine shop with vertical 3-axis milling, I built up a horizontal board over the bulb transport cradle, drew the section profile of the keel foil over the top of the "visually righted" bulb, and with a depth-plunge router (that Maktec MT360 with a mind of its own!), produced the foil step on 3 go. Expect some toasty lead chips with the router at >15,000 RPM...

Just to share with you guys some of the crazy things I do for this boat project...

2014-02-15-2 (forum).jpg

2014-02-15-4 (forum).jpg

2014-02-15-7 (forum).jpg

2014-02-15-9 (forum).jpg

The next challenge will be to produce 2 vertical bolt holes thru' the height of the bulb.

[Chad]

Looks great!
I used a similar process here:
http://i550knotracing.blogspot.com/2010 ... stuff.html

I used a little table-top drill press for the holes, but a long drill bit held by hand won't be too difficult. Lead is pretty soft and easy to drill. Without a drill press, it might be easier to use your router to create the countersink for the nut on the bottom, after drilling the through hole.

[micah202]

The bulb weighs 80kg (176 lb), or at least that's what I've been charged on the receipt...

...ummm,isn't the whole keel meant to be 150 to 185lbs?..or did you intend a heavier keel??



Rule 3.6
Maximum keel weight shall be 185 lbs (83.9kg) and minimum keel weight shall be 150lbs (68kg).

[Chad]

My keel strut came in around 10#, so he's right on track. He'll lose a couple pounds with the routing and drilling. If OD is ever an issue, it's lots easier to make a heavy keel lighter than to make a light one heavier...