JEM Watercraft

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Author:  goanywhere [ Thu Nov 24, 2011 5:49 pm ]
Post subject:  Re: Tolerances

You're right John. Half way through my build I began to realise that there was virtually nothing that could go wrong that couldn't be fixed. (BTW thanks for your encouragement that helped me to come to that realisation!)

It didn't mean that I got lazy or blaze, but it did mean that I started to get a bit more adventurous and willing to experiment. I ended up with a boat that wasn't perfect according to the plans but just what I wanted in terms of function - MY boat!

Not so easy to do with a 'cookie cutter' plastic job. :D :D

Author:  rodot [ Thu Nov 24, 2011 6:24 pm ]
Post subject:  Re: Tolerances

The hard bit about a first build, or a first anything for that matter is "what can I get away with, if I make a mistake"? The answer is probably a lot more than you think

I have to agree. It's only just a bit of wood and a lot of things can be corrected or worked around. I performed some skillful manipulations :roll: when I had a bit of drama with the Okwata, my first build.
Having said that, I know that Matts plans are spot on and have the added benifit of specific QA checks. I am sure that being as accurate as possible with the panels would make for a much easier build, particulary in the case of multi chine, multi panel boats. I took quite a lot of care cutting out and aligning the panels when splicing for the Northwind and was absolutely amazed how everything pulled together perfectly when stitched. I can honestly say that there were no problems whatsoever.
I've got to admit though, botching is a skill I very much admire. :wink:


Author:  Mark J [ Wed Jun 04, 2014 10:21 pm ]
Post subject:  Re: Tolerances

You can "cheat" quite a bit in stitch and glue especially on small boats. The downside is that it's just more epoxy.
Another downside is if you are finishing with the natural look. It's going to stick out like a sore thumb.

The best advice I can give to a newcomer is to slow down. Take your time with the layout and transferring the offsets.
If you are going to cut with a saber saw, invest in a good one. My preference is in the Bosch with the barrel grip, not the top grip. It gets my saw guiding hand down close to the work.

You don't have to be perfect, but the closer to perfect you are, the easier the panels will stitch together. It will be less unstitiching and restitching to get as close to right as you can. You are going to fight with it less and spend less time figuring out a suitable work around rather than making progress with building a boat.

Measure two or three times, cut once.

When I drag somebody into this hobby of mine my first priority is that they have a good experience with the whole process. That starts with the layout and the cutting. It is the foundation of the entire build. Usually if you create a problem you can't stomp it out with one action. As the build progresses it keeps coming back to life manifesting itself somewhere else in some form another. You may have precut all your parts and now find that a part doesn't fit exactly right and now you either buy more wood or have some obscene looking fillet.
Something that isn't explained or stressed enough is that these are "one offs" You can build 100 boats from the same plan with the same materials and you'll have a 100 different boats. There will be differences even if they are small differences. The custom yacht builders like Jarrett Bay boats that are built as one offs will tell you the same thing. No two of their hulls are alike even though half a dozen may have been built from the same print.
The only way to achieve perfect and precise from boat to boat is with a mold.

Author:  tx river rat [ Fri Jun 06, 2014 3:27 pm ]
Post subject:  Re: Tolerances

The difference in filets on a butt fit or a popsicle spacing or an 1/8 gap is no big deal and I challenge anyone to tell the difference after the filet is applied

Author:  Mark J [ Fri Jun 06, 2014 9:37 pm ]
Post subject:  Re: Tolerances

I wouldn't consider an 1/8 inch gap trying to cheat in fact, I don't butt anything. I'm trying to get a gap, but a uniform gap.
But we have all been beginners at one point. I still make mistakes.
I think everyone has had to cheat here and there to fix an error.

The errors start in the layout and the accuracy of the cuts.

Author:  tx river rat [ Fri Jun 06, 2014 10:24 pm ]
Post subject:  Re: Tolerances

I guess it depends on what you call a beginner,why dont you clarify that for me . I have built a couple boats.

Author:  Oldsparkey [ Sat Jun 07, 2014 8:40 am ]
Post subject:  Re: Tolerances

All the boats I have built ( which are quite a few ) the seams had no open gap between them. Each side fit right against the other side. After the seam was epoxied the seam looked like a human hair fell in the epoxy and dried.
Sometimes I had to sand the sides at a slight angle so they matched up better but that was mostly spot adjustments.
The outsides of the boats you could see the seams where the boards meet but they were not the wide seams that most folks like to do , I wanted mine as narrow and fine of a line as possible. That's the beauty of a butt joint , it can be made almost invisible if you take your time and do it that way. Or it can be as wide as you want to fill with wood flour and epoxy. Personally I do not like any gap in my seams.
( Down here Gap is ...The Gap , which is a store where you can buy Blue Jeans ) :roll:

Measure 3 times and then one more time before cutting anything. Lightly sand the edges to a respective ,slight , angle to fit together.

That's my way of making a wood boat and I do not expect anyone else to do it my way , each of us does it differently and our own way.


Author:  Mark J [ Sat Jun 07, 2014 9:50 am ]
Post subject:  Re: Tolerances

Chuck, gaps are more of a habit than anything. I've built planing and paddle. On a paddle boat neither is the wrong way. I may try some tight fitting on some of my current build.

Ron, I just don't know where to begin. I do realize this is one of the most poor forms of media there is because of the lack of the benefit of facial expression and tone of voice. It's up to the author to totally convey in words what not one person would construe to be offensive. Maybe I failed there. maybe someone is too emotional

I also realize I'm the new guy on your turf. Message boards tend to be like that especially boat building boards. Actually, I'm not new. I've been around a long time. Built a coupla of these boats as well as numerous others.
I teach stitch and glue and also am into boat restoration.

I thought I would start participating on this site (it needs some participation bad) and share a JEM build but I'm not in to marking trees.
You can have it.

Author:  Oldsparkey [ Sat Jun 07, 2014 10:55 am ]
Post subject:  Re: Tolerances

I forgot in my above post to state that when a person purchases the plans to make a boat ( or a kit ) then they should make it the way the designer suggests since he is the creator of that particular set of boat plans or kit and knows the best way of constructing it.

Read the instructions and steps of construction , then re-read them before starting the build. The read the 1st 3 or so steps and then start with the 1st step. This way you know why you are doing what you are doing and how it will work in junction with a couple of steps further along to make everything come together.
Most of all take your time and do not rush the process. :D

On the lighter side..........................
Mark J , said.
I thought I would start participating on this site (it needs some participation bad) and share a JEM build.

22,158 posts in 10 years = 2215.8 posts per year on building wood boats for personal use is not that bad but more participation is always welcome and a good thing. Or if you funked English class like I did ... More is more better.:D


Author:  tx river rat [ Sat Jun 07, 2014 11:15 am ]
Post subject:  Re: Tolerances

I cant help myself here,Everytime I am out in the boonies for a day or so I have to confess I will mark a tree occasionally. :lol:
I am not getting emotional on here if that was pointed at me but I do have my own beliefs and will state them or if I need a statement clarified I will as a question. The question , what you considered a beginner, was one of those.
I dont agree with your statement on the gaps being that important and let me explain why. On this forum you have four or more kinds of construction, stitch and glue , strip stitch and glue, full strip and batten . Everyone of these has a different need for glue lines , from the full striper with no visable glue lines and tight fitting joints to boats that are strip and glue that you can play with joint size and totally make no difference with in reason as long as your filet covers it and you achieve the look you want.
Now dont take this wrong but I dont know how to say it any other way. You came on here with some pretty strong statements and as an expert ( which you may be) criticizing not just anyone else opinion but also the operation of the forum. Now we dont know you so show us some boats you have built,a forum you run,tell us about your teaching expertise and your classes.
If I go to someone for medical advice I want to see his credentials.
Show us one of your Jem builds we might learn from it.
Hope this unruffles your feathers
Oh and as far as the forum goes ,everyone I participate in has slowed down since it was publicized that the Govt was collecting information from the internet and phones

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