My first design Aubigny 5.5m

A few years ago I was injured and I had alot of time on my hands. I had been out of sailing for 30 yrs. I was surfing the net and saw a homebuilt I liked-the i550. I wanted a bit more boat for some light open ocean sailing so I achieved something I always wanted to do- designed my own. I used the i550 build concept and enhanced it in many areas for more power, sail area, beam, and bulb weight. I have been into the build mildly recently over the last several weeks and hope you guys like it.

 

Aubigny 5.5m

Congratulations on doing your own boat! Hard to tell much from the render but I hope it goes well for you. Welcome to the forum!

 

Thanks Doug. Think of it as a bit bigger i550 but the same length. More MORC style cockpit wise. I really wanted something 2 could be comfortable sailing and quick. It has numbers really close to a Mini Transat but displaces 1180 lbs. Hull and rig about 800 lbs. I intend on doing some eXperimenting in some areas like a flat athwarthship bottom. If it goes well then I'll keep it. If not I'll put an arch bottom on it. I'm suspecting being a small boat it will not matter in the way it handles, but much easier to build.

I have a Prindle 18 rig for it. A bit heavy but it will help a bit in the ride. 215 lbs of lead in the bulb but almost 50% more than is needed to keep her upright. The sail area is a bit more than an i550 but its for low wind speeds. I added a foot to the beam at the shear to handle more sail and only 2 inches at the waterline. She has more cabin but a flat floor internally. My bunking will be handle in a lighter fashion serving two purposes at one time.

 

The boat is designed ideally for 3 or less. Single handed is very possible if just cruiseing.

 

To bring everyone up to my current status I started out with making a boat jig using a good trailer as a strongback. The jig in its basic form shown, has adjustable legs to level up and the trailer is square. When it comes time to lay up the hull it will get additional support.

 

The jig folds up and it is transportable.

 

I started making my bulb plug for my keel. Its a variant of the keel board which is a 63-0012 series variant.

 

The keel section initial thoughts.

 

Starting the plug glueing the cutouts in the closed cell foam.

 

Test aligning bulb plug assembly prior to glueing it all together.

 

Assembly glued together prior to sanding. Sanding will start at o, 90, 180, 270 deg. then 45 deg offset. Finally rounded to form. I finished the plug after I checked the dimensions.

 

Final result on bulb plug. I will cover the plug with glass for immersion into a split concrete mold.

 

During the shaping process I checked the dimensions with my large caliper.

 

There was further work to be completed. I planned on bolting the bulb vertically. The trend here is the bulb loosens a bit, racks the bolts some and then the ss bolt breaks. I have made a design to divert the side to side racking into movement in alignment of the attaching bolts thus reducing or eliminating the breakage. I plan on making statistical data on the bolts to verify and validate the design. I refer to it as the "keel/bulb interface". I'm not even sure if someone else hasn't tried it. Maybe someone might have a clue.

 

A little history and a note on my project purchases thus far. I wanted a boat that could handle a cat rig since 1990. I had a boat but it was MORC design and it kept occuring to me I wanted to blow out the rear quarters so it would jump out of its hole. Little did I realize 9 or 10 years later Chris B. Designed the i550. I stopped sailing due to my job and family. It was too much at the time. When I read the i550 was a cheap route to have a boat I said why not try this. My retirement was coming, there was a great example of a good design, I just needed to tweek it a bit for my purposes. Having a pocket crusier was a great idea. The builders of the i550 were having success finding hardware cheap to rig with. So I said "Hey that would be worth it to see if you can design a good fast boat while making it simpler to build than current model, build it, and keep the costs low at the same time....let's do it".

So after reviewing rigs I decided the best thing to do was go with a larger rig, give the boat more leverage to handle it, and keep the weight down for it's inherent quick speed off wind. I first purchased a used Prindle 18. It was built in the early 1980's. Believe it or not it is still sailable. The cost-$650 with trailer, extra tramp, sails. I think I came out great on that deal because I could use the trailer, make a great dive boat from the cat, use the rig, boom, rudders. Since then I bought some carbon fiber, glass, epoxy, western red cedar, a mainsheet track (Harken) and used mainsheet car and some smaller Items. My expense total thus far $1180. I'm expecting less than $1000 for ply, other glass etc. So before sails I will have spent $2200 or less on this project. I already have the lead and car tire shops will give you weights if you clue them in on your project.

I have worked in sailmaking and learned some of the trade. I have my own sails I designed waiting for final measurements. So sails will cost me labor to stitch it up for I have friends in the business. I could spend $2000 on sails and have more about what I need. So I'm expecting $4200-$5000 for a great "SportCruiser". This will be interesting to see if I hit my target expense.

At the moment I have my bulb plug almost finished, and I have my cedar core faired waiting for cf, fairing and glass. All in all my time is totaling 25 hrs. Next week I will get my cf so I'm expecting my keel board to be finished in two weeks at a leisure pace. Then its on to other tasks before assembling the hull in which I anticipate the simpler design easier to complete. It will be interesting thru the build process if I minimized much of the fairing required to have a good bottom..