Building Ninigret

[timo4352]

Made up my mind that I'm going to build Atkin's Ninigret. Plans are in hand and I'm readying myself, and my shop, to get started.
I want to start a build thread here to share my progress, and ask for your help, as I go along. It will also help me keep track of what I've done - right or wrong.
Of course, I already have some questions that are bouncing around in my head, but not quite ready to put them out there yet 'til I do my research. I'm not looking to alienate any would be help by asking too many stupid questions.
Things will start out kind of slow because I've got a lot of work to do to get my shop in order for a big project. Plus lots of studying the plans, and reading up on lofting, and boat building. This is not my first boat build - some of you may remember my stick-up sharpie, and gunning dory threads on the forum. So I've got some experience, but this is a bit bigger, more complicated undertaking for me. It should be fun. The boat will be used for fishing and fun on Lake Erie primarily. We have some inland lakes around northern Ohio too.
Here she is:

Isn't she pretty?

http://www.atkinboatplans.com/Articl...ret/index.html

[skaraborgcraft]

Pretty indeed. You did good jobs on your last builds, the wood on this one is just a bit longer......

[jpatrick]

I, for one, am quite excited about seeing your build progress. Ninigret is high on my list of possibles. Your thread just may put me over the top. A couple of ideas I've had:

1) Install a windscreen on top of the short cabin top. I don't see how it would be comfortable at all driving the boat with a face full of wind.

2) Add a fold-down canvas top to cover the helm and adjacent passenger seat. Something to both block wind and rain.

3) This last thing is a result of having a shear pin fail on my small electric outboard..... I'd make sure that the prop was accessible in the well for repairs.

Good luck on this. I'll add any helpful bits that I can!

Jeff

[swoody126]

gotz me a big ole glass of SWEET TEA & a large tub of

popcorn.jpg

LET THE FUN BEGIN

sw

[timo4352]

Here is a question that is bothering me...
In the one article about Ninigret, Mike O'Brien of Boat Design Quarterly says:

"Let's take a look at this skiff's hull lines. Healthy deadrise at the forward bottom warps down to about 15' amidships and disappears at the transom, which shows us a dead-flat lower edge. Atkin tells us to sheathe the bottom with high-quality 3/8" plywood.
We should understand that, when we wrap these sheets around the forefoot, they will bulge slightly outward. The frames in this area should be adjusted to fit."

So.... is there any way to know, or figure out, what this bulge would be so I could adjust those frames from the get-go? I'd rather not be padding out the frames if it is avoidable.

Also have seen one build blog the builder appears to have sheathed this area in 3 separate pieces; probably to make the bend, but it does not look fair. Shows flat spots. I don't want that.

Thanks.
Tim


Made some good progress cleaning out the shop yesterday.

[skaraborgcraft]

I had 8mm ply bow off straight section frames on my 13ft scale model. Knowing what i know now, i could take measurements from that and cut the frames for the new boat accordingly....but i wont. Not every sheet of ply will bend in the same way. The gaps wont be massive, so shimming out with some slithers and epoxy is not as great a task as maybe trying to sort a rolling bevel on a bit of frame stock. Sure, you can always add an inch to the siding and use a thin batten or ply to get an more accurate frame. There is only so much bevel work that can be done before hand from a lofting. If you are worried about the gap, you could run a longitudial stringer in from a flat area forward, you will still have a gap either side, and some say ply should only be fastened to stringers and not frames anyway.....

[stromborg]

I rather like the looks of Ninigret too and look forward to your build.

As to Mr. O'Brien's commentary; it's only commentary if he didn't (and I don't believe he did) actually build the boat. The design has been around long enough that you ought to be able to reach out to other builders for direct observations about what worked and what didn't.

[SKIP KILPATRICK]

Exciting, good looking boat.

[Oldad]

If you are concerned you could always spring a batten around the frames and see where and how much gap there is at that frame and adjust it, but I would wait and see and not worry until you see what you are dealing with. I say this because I believe it will not be a big deal to remedy. When I built my version it was not an issue at all. The hardest thing for me was bringing the sides together at the bow. Thankfully I had my son with me that day and between the two of us it was duck soup. Adjust/pad the frame if you must—no flat spots.

[jpatrick]

Why would a designer Who ought to know better) spec a material that will not conform to the lines?

Jeff

[Skiff Man]

We should understand that, when we wrap these sheets around the forefoot, they will bulge slightly outward. The frames in this area should be adjusted to fit."

So.... is there any way to know, or figure out, what this bulge would be so I could adjust those frames from the get-go? I'd rather not be padding out the frames if it is avoidable.

Yes. Loft the boat in plan. Draw a radial line through the mid-height point of each topsides frame station. That line will show how the plywood will lay in a flat plane when wrapped around the hull topsides. Then loft the boat in elevation and body plan. The 3-dimensional coordinates of the mid-height point of each frame can be scaled off of the plan drawing onto the elevation and body plan drawings.

[timo4352]

Yes. Loft the boat in plan. Draw a radial line through the mid-height point of each topsides frame station. That line will show how the plywood will lay in a flat plane when wrapped around the hull topsides. Then loft the boat in elevation and body plan. The 3-dimensional coordinates of the mid-height point of each frame can be scaled off of the plan drawing onto the elevation and body plan drawings.

... I wish I could say that this makes it instantly clear to me....but ....maybe once I get to actually doing the lofting it will click.
It may be so painfully simple that I can't see it. Sometimes I'm like that... then when it finally clicks -- I'm like what's wrong with me, why didn't I see that?
Dense I guess.

[jpatrick]

... I wish I could say that this makes it instantly clear to me....but ....maybe once I get to actually doing the lofting it will click.
It may be so painfully simple that I can't see it. Sometimes I'm like that... then when it finally clicks -- I'm like what's wrong with me, why didn't I see that?
Dense I guess.

No, I don't think you're dense. It doesn't make any sense to me either. I've read quite a few explanations of lofting. I can follow few of them. I think it's one of those things that's difficult to render into written language.

Jeff

[Skiff Man]

I've read quite a few explanations of lofting. I can follow few of them.

Same here. It is easier to do than to describe in words.

To attempt to clarify what I said above: You are plotting the radial line (from deckline to chine) in plan view first, then elevation second, then body plan third. The elevation will show at what height the radial line passes across the frame line. Then take that height and plot a point on the radial line on the body plan. The horizontal distance between this point and the frame line is the dimension you are after.

Good luck. I have really enjoyed following your other builds. Thanks for posting them on the forum.

[BBSebens]

This looks great. Will follow with great interest.

[timo4352]

I have been considering my options for gluing and fastening this hull. And looking back, I told myself that my next boat I did not want to slather in epoxy.
Pretty sure when these lines were drawn in 1964 that epoxy was not prevalent, or even an option. The plans do not mention any type of fastening schedule, or glue for that matter.
Even if I do epoxy the laps, I figure on using bronze ring shank nails attaching the plywood sheet and strakes to the stringers and frames. SB screws for the forward (hood?) end of the planks to the stem, and in other higher stress areas like the well, breasthook, etc.
If I forego the epoxying of the strakes altogether, I am then considering using copper rivets between the frames. The frames are 20 inches apart so 4 rivets between frames would give me 4 inch spacing. If I go that route then I am also considering LifeCalk polysulphide in the laps.
As an option to the epoxy or rivets, using 5200 or 4200 in the laps has crossed my mind also. If I did that do you think I would need any fastenings between the frames? (maybe not with 5200, but not sure about 4200) ?
I looked at resorcinol too - the 70 degree curing temp kinda throws a wrench in the works there, and I maybe gotta step up my carpentry a notch, or two. Would you glue the laps with resorcinol too - or not? Dumb question? Only dumb one is one you don't ask - or so I've heard...

[John Kohnen]

A batten won't show how a flat panel will wrap around the frames. It's not uncommon for designers to tell builders to pad out the forward frames of V-bottom boats to fit the way the plywood bends, IIRC, George Calkins did so with his Bartender plans. I suppose nowadays computer design programs can finger out the exact bulge needed, but it would have been tedious back in the good old days. As you say, don't worry about it.

I look forward to watching the build.

[jim_cricket]

Hi Timo,
Glad to see you tackling a larger project. I'm sure all things will become clear as you go. They usually do. You probably have seen this already, but a builder down near Charleston completed a Ninigret in the recent past. Morris Is. Boatworks. He cold molded the forefoot like I did for the Point Comfort 23. I've never had any communication with him, though I just got back from Charleston (didn't have time to look him up), but if I were to build Ninigret myself, I'd like to talk to him. I know he has shown that boat at the Georgetown SC Wooden Boat Show in the past. Anyway, good build pics on his website linked above.

I'll be following along with interest!
Cricket

[timo4352]

Thanks Jim
I have emailed back and forth a bit with Jack - talking about that forefoot. I had forgotten that you cold molded yours - I'll have to look back on it.
If I remember right your hull is 3/4" ply with no or few frames. Ninigret calls for 3/8" ply with 12 or 13 frames.
Jack did his bottom in 1/2", and double planked the forefoot in two layers of 1/4"

[jim_cricket]

That's right. My boat has a 3/4" thick meranti hull, floors only. No other framing. I wouldn't mind a 1/2" bottom on Ninigret myself. Do you plan on Occume? I struggled with my Matinicus garboards using 3/8" 5 ply Occume. Cracked a plank in the forefoot before I found 7 ply Shelman (no more of that, alas). Plywood quality might impact how easily you can coax a 3/8 bottom around that forefoot. I'll be watching with interest to see what you do.

[SBrookman]

Glad you decided to go ahead, another Ninigret build will be good. I'll let you know about getting Vendia, my shipment is in the US still waiting clearance from customs before I can get it.

[timo4352]

That's right. My boat has a 3/4" thick meranti hull, floors only. No other framing. I wouldn't mind a 1/2" bottom on Ninigret myself. Do you plan on Occume? I struggled with my Matinicus garboards using 3/8" 5 ply Occume. Cracked a plank in the forefoot before I found 7 ply Shelman (no more of that, alas). Plywood quality might impact how easily you can coax a 3/8 bottom around that forefoot. I'll be watching with interest to see what you do.

I'm planning on using Hydrotek meranti. Homestead Hardwoods shows 3/8" to be 7 ply, 1/2" at 9 ply.
Are you saying the 7 ply bent easier? Sounds bass-ackwards, but what do I know... learning something every day...

[jim_cricket]

The 7 ply didn't bend easier, but it took the bend without cracking. The plies are thinner, and in the case of the Shelman, more equal in thickness. If you have thin outer plies, the inner cross grain ones will be thicker, and offering no strength across the grain. I think the meranti will be stiffer, but not sure how thick the various plies will be in the Hydrotek panel. I believe the original spec from the Atkins was the Dutch Bruynzeel, long gone in the marketplace. That was a superior panel. My first boat in the mid 80's was made from 12' sheets of Bruynzeel. Beautiful stuff. Other more recent builders have certainly used single panel bottoms. Maybe it's not so tough a twist and bend. FWIW, the Tolman skiff uses 2 layers of 1/4" ply in the bow.

Steve B., that Vendia must be costing you a pretty penny! I keep asking my vendor if they will carry it. Not so far.

Cricket

[timo4352]

I have been considering my options for gluing and fastening this hull. And looking back, I told myself that my next boat I did not want to slather in epoxy.
Pretty sure when these lines were drawn in 1964 that epoxy was not prevalent, or even an option. The plans do not mention any type of fastening schedule, or glue for that matter.
Even if I do epoxy the laps, I figure on using bronze ring shank nails attaching the plywood sheet and strakes to the stringers and frames. SB screws for the forward (hood?) end of the planks to the stem, and in other higher stress areas like the well, breasthook, etc.
If I forego the epoxying of the strakes altogether, I am then considering using copper rivets between the frames. The frames are 20 inches apart so 4 rivets between frames would give me 4 inch spacing. If I go that route then I am also considering LifeCalk polysulphide in the laps.
As an option to the epoxy or rivets, using 5200 or 4200 in the laps has crossed my mind also. If I did that do you think I would need any fastenings between the frames? (maybe not with 5200, but not sure about 4200) ?
I looked at resorcinol too - the 70 degree curing temp kinda throws a wrench in the works there, and I maybe gotta step up my carpentry a notch, or two. Would you glue the laps with resorcinol too - or not? Dumb question? Only dumb one is one you don't ask - or so I've heard...

Soooo... no thoughts on the fastenings?

[timo4352]

Thanks Gib
That's what I'm looking for is some real world experience in different methods....what worked and what didn't....
I have thought about clinch nails too. I'll have to study up on the Sika 291. A bit stickier than LifeCalk I assume...

[timo4352]

Perhaps Tim, but I wouldn't rely on it without the fasteners. It's a perfect match for clinch nails though.

Oh Yes, definitely with fasteners.
There is 20 inches between frames so I'm not sure I even want to do epoxy without a fastener or two....but then again the glued lap boats don't....
But I don't think this boat was intended for glued lap. Did they even have epoxy in 1964 when the plans were drawn? I'd guess not.

[BBSebens]

Oh Yes, definitely with fasteners.
There is 20 inches between frames so I'm not sure I even want to do epoxy without a fastener or two....but then again the glued lap boats don't....
But I don't think this boat was intended for glued lap. Did they even have epoxy in 1964 when the plans were drawn? I'd guess not.

A quick google tells me that epoxy was invented in the 30s. The Gougeon brothers founded West Systems in '69.

Glued lapstrake boats do not require any fasteners. I've got a 16' glued lap peapod. It only has 5 frames in it, mostly to hold the stringer that the thwarts are mounted too. Its quite strong and rigid. I've rolled it over on the lawn, and there was almost no deflection when it was on its gunwale (it has an inner and outer wale). Of course the requirements of Ninigret are quite different from a little peapod.


Sam Devlin has used the Stitch and Glue method to great effect, building some substantial vessels in that method. No fasteners needed that I'm aware of.

[Oldad]

No fasteners, glue lap with epoxy, thickened a bit with wood flour. Laps that might not quite lay tight held in place temporarily with a drywall screw driven through a plywood washer to apply pressure. Should not need many of those, take them out when cured, fill with aforementioned epoxy and wood flour to a putty like consistency.

[jpatrick]

Although a typical glued lap construction does (usually) rely on epoxy, it use if really fairly modest in the great scheme of things. I would not ever describe it as having to be "slathered."

Were I to build Ninigret, and I may, I will most definitely use thickened epoxy to glue the laps and other areas. And following a belt and suspenders approach, the addition of screws to hold planking to all frames, stem, transom, etc is well worth the time and expense. I don't think that reinforcing all the laps with clinched nails or rivets is necessary.

Jeff

[Oldad]

And, if you are careful, you may wipe the slight squeeze out with your gloved finger into a neat cove at the bottom of each lap. No slathering.

[stromborg]

Picture snatched off the internet

This looks like a classic frame with chine log construction to me. No doubt back in the day they would have used one marine-type glue or another backed up with nails or screws. Modern day epoxy is a wonderful adhesive, if it were my build I would use it and only enough metal fasteners to hold the pieces together while the epoxy cures. My opinion is that rivets in the laps would simply be introducing unnecessary holes in the boat if you use a good quality epoxy.

[timo4352]

Thanks guys.
I'm taking it all in. Mulling it over.
One thing that's bugging me about epoxy is it being brittle. Something is telling me I want something with some flex to it. I've considered G-Flex to solve that worry. The other glues 5200, 4200, Sika have some flex.
Still undecided, but I'm getting some sample boat nails and roves from Fearing Design to check them out.
I appreciate the input.

[Oldad]

Take a look at this thread,Thread: "Skål Sandy!” a Caledonia Yawl Build in Cream Ridge NJ

the building of a Caledonia Yawl. Glued lap (epoxy) no frames, no rivets I have sailed in Geoff Kerr's CL that was built many years ago using this method, still like new.

[stromborg]

One thing that's bugging me about epoxy is it being brittle. Something is telling me I want something with some flex to it. I've considered G-Flex to solve that worry. The other glues 5200, 4200, Sika have some flex.

The number of old epoxy-glued boats still floating around ought to dispel your concerns. What drives your idea that it is somehow too brittle?

[timo4352]

some reading on brittleness:
https://epoxyworks.com/index.php/if-...more-flexible/

https://www.jamestowndistributors.co...t.do?docId=357

my fears could be unfounded, but maybe not...

...or maybe deep down inside I just don't want to use epoxy for this build...IDK...