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General Discussion Tolman Skiffs / Re: Looking for a wide body to look at
« Last post by Sprig1 on February 26, 2024, 04:27:30 PM »
  Thanks Steve V were you located?
    Kobuk thanks for the insight!
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Introduce Yourself / Re: Hello from Finland (and a question...)
« Last post by jallii on February 26, 2024, 12:08:18 PM »
Hi there Pekka.
Nice to know someone else from Finland found out about Tollman designs...

About knowing how high the beams must be for the boat to be self bailing...

There is basically only 2 ways to approach the problem...

1. You can try to estimate the weight of everything that comes to the boat and then try to estimate how high the corresponding volume of the
underwater part of the boat is...  So its basically a matter of making a note of the weight of everything in a table and also measuring and calculating the underwater volume....   Archimedes knew it very long time ago... weight and volume must match...  You will probably forget something and make measuring mistakes... so keep a safety margin for errors. Of course if someone else has built a "sister boat" that is reasonably similar you can base your estimate on that... Again remember to keep the safety margin.  You may, or you may not succeed. It depends as people already pointed out on many things... but what else can you do... All this calculating is of course much easier with a computer software that takes care of the tedious tasks, but learning a CAD software that is made for for designing boats and building a 3D model is also a lot of work... but if you want to do it I can recommend Delftship. You can use the basic edition for free, but if you want to get the 2D development files from the 3D model you need to buy the license.  Freeship does it for free and is opensource, but its development has been in a standstill for a long time.
 
2. You can simply build the boat according to Renns instruction, except for one thing. Do not attach the DECK decking plywood before you float the boat and test where the waterline is. You can then adjust the height by simply adding stuff below the decking plywood.  When floating the boat you compensate for stuff thats not built yet with sandbags, water canisters.... whatever.. This way you can get a more accurate estimate of the final waterline height with less complexity.


Hi KenB .. Sorry for not being here for a while... trying to catch up...

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Introduce Yourself / Re: Hello from Finland (and a question...)
« Last post by KenB on February 26, 2024, 09:11:52 AM »
Congrats on making some sawdust! I am also really happy to read that you found Tolman Skiffs the same way I did! It sounds like you are headed down the right path, it should be an awesome boat when you get done. Build fast, go fishing!


I'll make my stringers from "versalam" / LVL-beam. I'm planning to build a self bailing floor. Is the standard 6" stringer high enough to keep the floor above water level when the boat is loaded? The book seems to suggest so but I could not find a definitive answer. I also did some crude calculations that might suggest the same. However, many builders seem to raise the stringers an inch or two. I would like to keep the floor as low as possible but naturally above the water level.


I have some experience with this.  The short answer is that "No, a deck built directly on top of the stringers will probably not be self-bailing."  To be self-bailing, the deck is to be 1 inch above the water (with the engine tilted up). I just passed the ABYC standards course, so while I think this is a stupid arbitrary measurement, it's the industry standard. Based on gas tanks, batteries, etc. adjust your decks according. There are 2 reasons for self-bailing deck: The first is if you take water over bow, a self-bailing deck with scuppers will clear the water much faster than any other method. Second is that at rest (e.g. mooring, slip) a self-bailing deck will use the bilge pumps much less.

I like scuppers. Just big holes in the transom, can add flappers if you want. Keep it simple. For sure, don't cut any holes in your boat until you absolutely need them.

2 ways to raise the decks:
1) Build the boat per the directions in the book. Add a 2x4 or laminated plywood on top of the stringers to raise the deck. I think the probably the best approach. A few comments:
- If you glass the deck the hull sides on top of 2x4 framing, I don't think you don't need to those frames on page 112, figure 13-1. Deck is structural.
- don't do the stupid plywood frame things, as found in the 4 part Wooden Boat magazine build. waste of time and material, just captures more water under the deck...
- Run the 2x4 crosswise at the seam of each deck ply, and glass in little risers where each 2x4 hits the side of the hull. You can make these a little short, so the 2x4 piece bows up in the middle. This allows the deck to be crowned in the middle a bit, which helps water run off, but also makes the plywood a little stronger or at least less flexible. You can also get a crown by shaving down the ends of the 2x4 cross pieces. If you do crown your deck and plan to make your own deck hatches, you might need to adjust the hatch cover a bit.
- I'd also suggest making the bow section an inch or so higher... you want the deck higher at the bow so that it drains at rest, especially if you put fat guys up front.
- Lots of discussion about whether to glass the bottom side of the ply. For sure you need to epoxy it. But it is worth the cost to glass the bottom? For me yes, glassing one layer of 10oz does stiffen the deck plywood noticeably. No wrong answers though.
- Feel free to use the PL 3x construction grade stuff to attach decks to stringers, there are apparently some production boats doing this now? Still  need to glass/tape to the sides though.


2) Increased the height of the stringers themselves, by adding height to the tables on pages 79-80, tables 9-10, 9-11 9-12
- you also have to adjust the height of the stringer horse on page 104 figure 12-4.
- I ended up cutting into the stingers for the 2x4 cross pieces anyway... so you don't save a ton of time doing this.

Have you thought about doing a casing platform at the bow? Instead of the storage thing? Thats another change I made. Basically, you make the same bow thing as in the book, but drop it down so its about a foot higher than your deck. I cut a trapezoidal hatch, instead of buying an aftermarket hatch. Smaller diameter lip from 2x4 for the hatch to sit on, with a piano hinge.

One last comment is that from my experience with seacrafts, having airflow under the deck is generally a better idea that trying to seal off chambers. On the little Jallii skiff, the gap between the bowstem and casting deck is actually open. And the small deck is open at both the rear and the front. This so air can go through everywhere. It is my experience that if you trap air in a chamber on a boat, even if you do a good job glassing everything, the plywood eventually goes punky; airflow saves plywood.
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Introduce Yourself / Re: Hello from Finland (and a question...)
« Last post by TNeilson on February 26, 2024, 08:32:29 AM »
I am building a 20-foot standard and have not been able to come up with a way to give me any real confidence in if the designed deck height will be above or below the water line yet. I am building a tiller-steered boat, so while operating my weight will probably be further aft than yours, but I have a 30-gallon built in fuel tank between the stringers located roughly where a center console would be. Power is a 60-hp yamaha four stroke and no kicker, and stringers are as designed by Renn with 1/2-inch ply deck.

There are so many variable in total weight, weight distribution, and dynamic weight (e.g., where operator, passengers, and equipment will be while on the water) between all of the different builds, that I'm currently planning to wait to cut the scupper holes until I've floated the boat and get a sense of where the water line sits. This also means I haven't decided on scupper type yet either. It also seems that the standard is a less popular hull to build, at least among people that are active on this forum, which makes for limited information on existing boats.

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General Discussion Tolman Skiffs / Re: Looking for a wide body to look at
« Last post by Kobuk on February 25, 2024, 08:39:19 PM »
Kobuk that would be quite a trip! Alaska is on my bucket list. I read one of your posts that you said you would extend your Widebody next time. How long would you build it. I’m thinking of building at least 24 feet. Thanks
Well, if you make it up here give me a shout!  Mine is 22', which is great for everything I do with it (1-2 week solo fishing/exploring trips, and day trips with friends aboard), but if I gained a partner again and wanted a fully enclosed pilot house, a larger bunk and a few more creature comforts (and assuming I wanted to build a second time) I would go to 26' and power it with a 115.
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General Discussion Tolman Skiffs / Re: Looking for a wide body to look at
« Last post by Steve V on February 25, 2024, 05:03:47 PM »
I don't have a widebody, but you are welcome to look at our Jumbo. We are located in Southern Maryland. I looked at Dave Wilson's Jumbo also, and another jumbo he was working on. It definitely gave me the itch to get started making saw dust when I saw what was possible.
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General Discussion Tolman Skiffs / Re: Looking for a wide body to look at
« Last post by Sprig1 on February 25, 2024, 05:00:08 PM »
 Kobuk that would be quite a trip! Alaska is on my bucket list. I read one of your posts that you said you would extend your Widebody next time. How long would you build it. I’m thinking of building at least 24 feet. Thanks
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Boats For Sale / CNC cut BIA outboard mounting template - free
« Last post by skookum on February 25, 2024, 12:30:13 PM »
I have a free CNC cut BIA outboard mounting template in 3/4" plywood up for grabs.

CNC file graciously provided by pfithian.

Pickup in Lyle, WA
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