Atkin Fore An' Aft Cutter Model

[jsjpd1]

I've had plans for Atkin's 28'8" Fore An' Aft Cutter and while I'm not set up to build a full sized version at the moment, I thought I would build one in one inch equal to one foot scale. That way I can work out a materials list for the full sized version, hopefully figure out some of the problems to be faced in the build, and have fun winter project to work on. I also thought I'd share my progress as I went along.



This is the first time I've actually lofted out a set of plans and there have been some head scratching moments. Especially when buttocks height and waterline half breath were in impossible relation to each other at station 9. After a lot of erasing I think I finally have it pretty well sorted out.





The backbone is pretty chunky, with keel coming in at 6"x8"x22' and most of the other pieces 10" wide or better. So far I've got all of the stem, keel, and stern post cut out.



More to come as it gets done.
Jim

[sailboy3]

Fun. I look forward to future progress reports.

[PeterSibley]

Fun ! I lofted her full size once .

[Paul Pless]

Watching with interest!

[Jim Ledger]

Watching with interest also.

If I may ask a question, I was wondering about the tumblehome on the transom. It seems to develop rather quickly from what I believe is Station 12, which shows no tumblehome, to the transom.

[P-man]

thanks for posting this. i plan on attempting my own scale model soon so have a lot to learn. if i may ask, what are you using to cut the wood?

thanks,
perry

[JoshuaIII]

Love the Fore an' aft, actually we almost build this boat and took us a few months to decide between this and the one we are building!

Look forward to your update.

[Alex Low]

Nice.

This boat is definitely on the list.

You can sort of see the tumblehome develop in this photo:



How can you beat this!!



Alex

[donald branscom]

Thanks for sharing your photos and story with us.
I am sure building the model will come in handy if you build the full size boat.
The lead weights with copper hooks are something I have never seen. Is that your idea?

[PeterSibley]

Watching with interest also. If I may ask a question, I was wondering about the tumblehome on the transom. It seems to develop rather quickly from what I believe is Station 12, which shows no tumblehome, to the transom.

Jim, I think that was Mr Atkin's attempt to design the hardest possible transom and aft bulwark capping for the builder to work out !

[jsjpd1]

^That's funny Peter, that's my take too!

This is what Mr. Atkin had to say about it.

The deck line aft over the counters is well-rounded which gets away from the boxlike angles where the sides meet the transom. While this rounding off of the deck line aft complicates the construction, I feel the rounding process is well worth while.

[jsjpd1]

thanks for posting this. i plan on attempting my own scale model soon so have a lot to learn. if i may ask, what are you using to cut the wood?

thanks,
perry

Hey Perry, So far it's been all table saw and band saw work with just a little bit of clean up using a small block plane, chisel or sand paper.

Love the Fore an' aft, actually we almost build this boat and took us a few months to decide between this and the one we are building!

Look forward to your update.

That's interesting Stephan, what made you settle on the Gartside design instead?

The lead weights with copper hooks are something I have never seen. Is that your idea?

Hey Donald, It's probably been done many times before. I had a little lead left over from another project a just used my imagination to recreate what I thought drafting ducks looked like. They weigh just a little over six pounds a piece, the copper is just stripped 110v with twist inside the lead so it can't come out. The mold was cut out of 3 chunks of 2x6 and just quick clamped together. By the time the fourth one was poured it was time for a new mold. After they were cool they were dipped in shellac a few time to give them a protective coating. They've been very useful. It would be nice to have a few more.

Jim

[jsjpd1]

Nice.

This boat is definitely on the list.

You can sort of see the tumblehome develop in this photo....

Alex

I love those pictures Alex! The second one is my desk top background on my computer.

Jim

[Tom Freeman]

I have a lot to learn about lofting, so I will be following carefully. Thanks for posting.

[JoshuaIII]

That's interesting Stephan, what made you settle on the Gartside design instead?

Hey Jim,
I didn't really like the inside ballast of the Fore an' aft, but that's a matter of choice. The main reason was that Atkins pass away, Gartside is alive and well available to builders. So we were able to have modification done by him to suit more our need or bug him when we have a ?.

[jsjpd1]

I have a lot to learn about lofting, so I will be following carefully. Thanks for posting.

Me too Tom. Hopefully it will start to make sense soon!

It's odd.

There's tumblehome at St 4, 5, 6, 7, 8, 9 and the transom,
but none at 10, 11, C(?) and 12.

I, too, am very interested, because I'm lofting, at small scale, a different Atkin boat.
It does use up erasers, doesn't it?
I'd love to see more detail of the issues you had with transferring from the offsets to the loft floor.

Watching with interest also.

If I may ask a question, I was wondering about the tumblehome on the transom. It seems to develop rather quickly from what I believe is Station 12, which shows no tumblehome, to the transom.

This is why I'm glad I posted, the tumble home at the transom is indeed there to help round the deck as designed, and it does develop very quickly. But thanks to you guys questioning it I went back and rechecked my points 11, C, and 12 were all off at the cap rail.



Here are the corrected stations.



The tumble home still develops out of thin air but it should be slightly easier to get to.

Jim

[jsjpd1]

Hey Jim,
I didn't really like the inside ballast of the Fore an' aft, but that's a matter of choice. The main reason was that Atkins pass away, Gartside is alive and well available to builders. So we were able to have modification done by him to suit more our need or bug him when we have a ?.

Having a designer who's alive and well to talk to is a definite plus.

[jsjpd1]

So far I've had two major issues with lofting the first was finding battens thin and supple enough to take the curves without breaking. I finally found success with a mahogany planed down to just under a 1/16th of and inch. The second (and more troubling) issue is which set of points do you pick when they don't line up.

Here is the most egregious example. The dividers in this picture are set at where half breadth of WL 1 should fall at station 9 according to the offsets.



Here on the body plan that point is about half way between sta. 9 and sta. 10.



Now the height of buttock 1 lines up perfectly between the profile and body plan.





Which one is right? For better or worse I drew out the profile, half-breadths, and diagonals before I started the body plan. As individual views they all look good, it's only trying to reconcile them in the body plan that things get dicey. To move the water line at 9 means that is also needs to move at 8 and 10 at a minimium. The same is true if I move the buttock at 9 instead. Maybe they should both be adjusted.... at which point a lot of hair pulling and head scratching ensued on my part. Eventually I decided to adjust the water line, I think it'll work.

Jim

[P.L.Lenihan]

How can you beat this!!



Alex

I do not know about beating it Alex, but the following photo gives me wobbly knees every time I see it.Perhaps you know this boat?


































Cheers!



Peter

[P.L.Lenihan]

It is a good question Jim and I think if I were in a similar situation I would fall back to the rule which states: a fair line supercedes the offsets...or something to that effect.

God lucdk!


Cheers!


Peter

[PeterSibley]

Jim, I mentioned earlier that I had lofted the lines full size, well I found quite a few errors, quite large ones and not knowing what to do or about the advice available here I set things aside and didn't continue. My confidence sorely shaken .

These days I know enough to work my way through the process. If you feel you want to be sure find a copy of Chapelle's "Yacht Designing and Planning". It takes you gently through the drawing process and will help you correct the errors. I tend to fairing diagonals as I think them most important as they are the plank runs. Have you run them yet ? There is one very close to your worrisome point that might help.

But it all has to match so keep at it and power to your pencil.

[PeterSibley]

BTW, if you need more battens I have great success with acrylic in various thicknesses from the plastics shop and have even run some through a thickness sander to get very thin ones ..

[jsjpd1]

Thanks for the advice and encouragement Mr Sibley and Monsieur Lenihan. I have run the diagonals and I think they are close, in fact I thought I was pretty much there, but now that I've taken a few photos to share, I see some spots I may have missed.

I think I have that book around here somewhere Peter, I'll have to look for it. I understand what you mean about wanting to give up when things just aren't lining up. I was just about there at one point, but once I decided on one point or another and just moved forward it got easier. It does raise the question in my mind though, what are the defining features of any given design? At what point in fairing the lines do you end up with a different boat? But then I think, "don't be dense, it just a boat. Get on with it already!"

Jim

[jsjpd1]

I went back and redrew sta 9 on the body plan, scaled directly from the plan sheet and it followed the the mark at WL 1. It also completely screwed up the diagonals and buttocks lines for several frames. Since I've already faired every thing out the other way I think I'm going to stick with it, for better or worse.



I also glued up the backbone.



Jim

[PeterSibley]

Jim, are you going with the line with the horrible black marks ? The top one ? It looks about right .

[jsjpd1]

That's right Peter, the one you put the arrows on.

Jim

[PeterSibley]

Billy Atkin was a very busy man, a new design contracted to MotorBoating every month plus outside work. No wonder there are mistakes but it is hard for the new comer to work around ! DAMHIK !

[jsjpd1]

You're definitely right there! Almost makes me think I should have chosen something a little easier for a first attempt at lofting, but where would the fun in that be?

[PeterSibley]

Fore'n Aft will be a beautiful model ,you can look at her a while then start the real one .

[jsjpd1]

Fore'n Aft will be a beautiful model ,you can look at her a while then start the real one .

I'm hoping to build the required shed starting in the spring. In the mean time it's a sunny 7 F here today so I will be content to keep plugging away at the model.

In that vein, I thought I'd take a shot at casting a keel for my little cutter.

Here's the mold cut out.



and just after the pour.



Then I cleaned up the top with a router.



So far so good. Unfortunately when I took it out of the mold I discovered that I'd had a bid of a flow problem in the closed end. Bummer.





Jim

[Jim Ledger]

You need to drill a vent hole.

What's making the texture on the side of the lead pour?

[Songololo]

Nothing a wee bit of epoxied shot won't fix

[jsjpd1]

You need to drill a vent hole.

What's making the texture on the side of the lead pour?

Thanks Jim, I'll try that.

The texture showed up because I used a couple of left over pieces of pre-finished oak flooring for the mold and the finish came up during the pour.

Nothing a wee bit of epoxied shot won't fix

This crossed my mind as well, but I ruled it out for two reasons. The first practical, I've run out of epoxy and don't have any at the moment. The second somewhat less practical, I would like to stick as close as is reasonable to how a full sized one would be made, and if I muffed it up full sized I would likely be starting over.

Jim

[JoshuaIII]

and if I muffed it up full sized I would likely be starting over.

When you will have 4000 pounds of lead melted in one single ingot, believe me you will do everything you can to don't start over. Countless boat have epoxy on the lead to fix some minor pouring issue. Just cutting that block of lead so you can drop it into the bath will be a nightmare...as any saw the blade will try to solder with the lead without speaking of toxic lead dust everywhere and of the week wasted to build another mold.

[PeterSibley]

When you will have 4000 pounds of lead melted in one single ingot, believe me you will do everything you can to don't start over. Countless boat have epoxy on the lead to fix some minor pouring issue. Just cutting that block of lead so you can drop it into the bath will be a nightmare...as any saw the blade will try to solder with the lead without speaking of toxic lead dust everywhere and of the week wasted to build another mold.

A chainsaw with a fair dose of kerosene in the cut works well if slowly.The main danger is the flying chips .... they hurt !

[PeterSibley]

You need to drill a vent hole.

What's making the texture on the side of the lead pour?

Beat me to it !

Jim, how about a bit of scrap aluminium sheet to line the mould ? If you pour just melted (not too hot) and vented as JL suggests it will come out well.

[jsjpd1]

Well, third time was the charm on the ballast. I had heat and torch issues on try number two, and on reflection Stephane, you are right I would want a full sized casting to be right the first time but would probably do what could be done to repair a bad one rather than have to have a do over. On the plus side having a couple do overs in this case turn out pretty well. The casting looks nice and I'm pleased with the way it turn out, I very much appreciated the advice to add a vent hole and will need to remember that in the future.



I also spent some time fairing in the stem/keel/stern post.



And I've started cutting out the station molds. The outside line is the lofted line to the outside of the planking, the inside line being the actual station mold. It took a while to get my head around the idea of backing out the planking.



Here's Sta. 6 cut out.



I think it'll work.
Jim

[PeterSibley]

I'm going to enjoy this Jim, it will be fun watching the planking progress .

[JoshuaIII]

looking forward to the next update!

[Tom Freeman]

I'm glad that you are a little ways ahead of me with your project. It is fun to watch and learn.

[jsjpd1]

I'm going to enjoy this Jim, it will be fun watching the planking progress.

The planking process should be 'interesting' Peter. Planking is not something I've had a lot of practice with.

I'm glad that you are a little ways ahead of me with your project. It is fun to watch and learn.

I'm glad you think so Tom, I'm sorta kinda hoping you'll breeze right past me.


When picking out the stations to cut the molds, I noticed that I had introduced a fairly significant error where the sections flow into the keel. The keel is straight sided from stations 10 to 4 and but I brought the curve of the sections to the bottom of the keel instead of to the rabbit line. Consequently, the stations were significantly wider at the rabbit then reality would allow for. Fortunately, it was a simple task to refair the bottom sections and check that diagonal 1 still worked.

If you look close you can see where the old line was outside of the bottom most nails.


Here is the growing pile of station molds.



And the assembly.





Next up on the to-do list, is to cut the rabbit, fit the ballast, and set up the molds on the backbone structure.

Or something like that.
Jim

[PeterSibley]

If you are planning to build full size one day Jim you will find this a most valuable exercise. Making your errors and doing your learning at 12 to 1 scale is relatively painless and certainly cheap !

Will you be using scale bent frames ?

[jsjpd1]

If you are planning to build full size one day Jim you will find this a most valuable exercise. Making your errors and doing your learning at 12 to 1 scale is relatively painless and certainly cheap !

Will you be using scale bent frames ?

That's the idea Peter. I have some left over yellow cedar blanks from the framing of the SOF rowboat I built last winter. It should be just the thing for frames bent to scale. The framing is supposed to be 1 1/8" square. That works out to about 1/8th of an inch square in scale. The AYC I have is superb and should work at that scale with out problems. I will need to set up a small steam box though.

Jim

[PeterSibley]

I will need to set up a small steam box though.

Jim

The tiny hoses are going to be fun !

[jsjpd1]

The tiny hoses are going to be fun !

.

[JoshuaIII]

Really enjoying this, nice work... I was dreaming of steam bent frames for it, but thought I was too extreme!

That will be nice to see

[jsjpd1]

Can there be such a thing as too extreme Stephane?

What I'm having a hard time with at the moment is trying to decide whether or not now is the time to attach the ballast, and how am I going to find the room to put in the wee keel bolts through the floors.

Jim

[JoshuaIII]

Can there be such a thing as too extreme Stephane?

Well does making it blind folded would be too extreme?

I think you may cheat a bit for the ballast and do a old fashion way with the bolt going only into the keel... Drilling into the lead and gluing some small rod into that like if the bolt were cast in...

Just a idea, as this is small to work with.

[J.Madison]

If I remember right that boat is drawn with the ballast bolts going up through the keel but not through floors. It would certainly be easier to do that on a small scale.

I have long loved Fore an' Aft and was pretty set on building it as the "big boat" to sail away on. I am now slowly and somewhat grudgingly moving to Gartside's 30' cutter as a more refined iteration of the same thing. Someday... Someday. But I will very much enjoy watching this little boat come together. Maybe it will sway me back the other way.

[jsjpd1]

Just drifting the ballast to the keel sounds like a workable solution. Thanks for the suggestion.