mainiac68

Hi all. I have been out of rc for awhile but have moved to Florida and am digging out my stuff. I need to make a new keel for my Acboat. It is a Bahamut hull I believe and would not be a competive boat by todays standards but that's not what it is for. I don't know what size or shape the keel should be. I would like to make it with balsa and carbo fiber. This sound right?

thorsail

hey mainiac68

I have this in my reference card file , maybe you can also check here......
.
www.orgsites.com/mi/model-ac-class

I believe this to be a current AC class website
Allan

eltoro

Hi Maniac,

I scratch built my Bahamut utilizing the Plans from AMYA which are still available.[link]http://www.shipsstoremodelyacht.com/Books,%20Plans,%20Etc.htm[/link].
As shown, the plans offer a full size template of the keel. The dimensions of the keel are: the top chord length is 6 7/8", bottom chord is 6 3/4". Length of keel (not including bulb) is 11 1/2".

I made my keel with a backbone of 1/4" thick aluminium tongue, which slides into the keel box. The fairing was of wood and fiberglass combination. Decidedly low-tech but it was one of my first scratch building projects. The keel design is surprisingly rather shallow for caring such a big sail rig but as you probably know the AC Class as under gone a complete revision, deeper keels, even bigger rigs and different hull designs.

My boat will (hopefully) see the waves for the first time this sailing season. It is just for free sailing pleasure. The Bahamut is an outdated design not that racing was a consideration.There is no such AC boats anywhere close to my location. I made it as a semi scale, learning building experience. In retrospect I should of chosen a class boat with more information available. The resources for this class is sadly lacking compared to many other better documented Classes. There is a website specific to these boats, but last time I checked, it had not been updated for eons.

In regards to using carbon fiber in your keel construction. I have only built one keel utilizing carbon fiber and that was with a much smaller craft ( a 1/20th AC Boat) so I not really qualified to offer advice other than, the keel bulb weights in at a rather hefty 17 lbs. So needless to say whatever materials you decide to use, the keel will have to be sturdily build to withstand the twisting force and other factors etc. with such a weight. Not to mention it was rather challenging casting 17 lbs. of lead when I built mind. Good luck with your AC Boat. they are a striking craft out on the water. At least I hope so when I get mine out there.

Tory

mainiac68

Thanks for that post Tory. If I can figure out how, I'll post some pics of my AC. I like what you did for scale like deck. Imade the weight and keel previouslyby using apiece of stainless. It's pretty big and heavy 15" from bottom of hull to bottom of bulb and 21pounds for the keel and bulb assy. I just took measurements from a couple keels I had seen for smaller boats and scaled it up. A couple people tried to get a group going in Maine where I lived all my life but only a handful of us built them. I was lookingto make the boat a little morenimbleand responsivein a light to medium breeze so thought I woild try to make one as originally designed..This keel/bulb does keep it anchored and it takes a very strong breeze to lay her down. I guess that's my concern with the original plan. I'll be very interested to know how she sails (if she is tende at all). I haven't even dug out my mast and sails yet but plan to soon. I haven't located any down here in southwest Florida yet but hope to as well.


Thanks,

Fred

mainiac68

Thanks Allan. This class is indeed tough to find details for.This hull wouldn't compete well with the "new rule" boats but that's not what I'm doing. It's pure pleasure of watching the big boat cut through the water.

Fred