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boat plans

Posted: Fri Jan 14, 2022 9:45 pm
by ivan the terrible
evening all
I'm starting to think about what sort of boat to build, want something that wont take too long to build and I'm thinking aluminium or steel (I can tig or mig weld alley and I have all the facilities to hand) needs to be around 20 feet long and a "comfortable" width.
any ideas of available plans ?
thanks in advance.

Re: boat plans

Posted: Fri Jan 14, 2022 10:44 pm
by barts
I'd start with figuring out:
  • How many people you want to carry.
  • Type of use:
    • Short tours from the dock, typical of steamboat meets.
    • All-day steaming (impact on fuel, level of shelter/shade).
    • Overnight camping (sleeping on shore, but lots to carry).
  • Type of fuel:
    • oil - built-in or portable tank?
    • propane - bulky compared to oil, safety issues.
    • wood - bulky compared to both propane and oil.
  • Where you're going to use the boat:
    • fresh/salt
    • sheltered/open
  • What displacement limits you have in terms of moving the boat. Our 19' Otter is easily towed at less than 2000 lbs on trailer even w/ a sedan;
    our 26' Rainbow weighs 7000 lbs on her trailer and requires a full size truck/SUV.
Note that steel in that length will be either quite heavy or the plating very thin, aluminum boats will require careful attention to electrolysis issues, esp. in salt water.
Hull forms suitable for plywood are generally suitable for metal, but framing of course will be completely different.

- Bart

Re: boat plans

Posted: Fri Jan 14, 2022 11:03 pm
by barts
Addendum:

You may find something like https://www.selway-fisher.com/Steamup20.htm#SAPPHIRE suitable. From a practical standpoint, I'd avoid the separate cockpit configuration as it would make single handing more difficult, but I then I often anchor out or tie onto a mooring buoy by myself and then row to shore.

Note that if you're willing to accept hull forms achievable by bending sheet materials, epoxy + plywood is likely the easiest/quickest form of construction, in as much as any boat building can be easy or quick :).

- Bart

Re: boat plans

Posted: Sat Jan 15, 2022 12:47 am
by ivan the terrible
barts wrote:
Fri Jan 14, 2022 11:03 pm
Addendum:

You may find something like https://www.selway-fisher.com/Steamup20.htm#SAPPHIRE suitable. From a practical standpoint, I'd avoid the separate cockpit configuration as it would make single handing more difficult, but I then I often anchor out or tie onto a mooring buoy by myself and then row to shore.

Note that if you're willing to accept hull forms achievable by bending sheet materials, epoxy + plywood is likely the easiest/quickest form of construction, in as much as any boat building can be easy or quick :).

- Bart
hey Bart thanks for the response I guess all I'm after is a quick and nasty way to get my engine and boiler into a hull quickly and cheaply and then hopefully build a replica of Alice (if I can find the original plans) at a later date. I'm also looking around for X sailboat hulls etc but as a bit of a metal moulder I fancy having a go 😊.
would only be rivers, canals and lakes and I'm not after longevity.
I am a bit of a skinflint so be nice to get a look at some plans before I part with my hard earned buck 😊😎

Re: boat plans

Posted: Sun Jan 16, 2022 3:34 pm
by Lopez Mike
I agree with what Bart has said. I went the Stitch and Glue route and have no complaints except that it's a moderate pain to achieve the small area of compound curvature near the bow at the chine. Nothing is cheap these days. My materials bill for a 25' hull, plywood, glass cloth and resin, ran $5K USD.

If you really want to get a small hull in the water with the least amount of expense and work, I would go and find a small fiberglass sailboat that has a swing keel. These hulls are a dime a dozen these days. I would be surprised if you couldn't find one for free. You glass over the centerboard hole and add a shaft log and bearing. They already have a transom hung rudder and are easily driven. Just whack off the deck and cabin and add a few modest bulkheads.

They are wider than a traditional launch hull but not so as to be a big issue. And this solution will get you on the water with a usable boat in a relative hurry.

As an example, look for a Catalina 22. There are many others. If it doesn't work out in the long run, the education and fun you will have will be priceless.

Mike

Re: boat plans

Posted: Sun Jan 16, 2022 3:51 pm
by DetroiTug
This would be a good fast build in steel or aluminum. Steel: 1/4x2 frames, 3/8 x3 keel, 12 GA on the bottom 14 GA on the sides. Need a plasma arc to cut the skin. Need to calculate weight displacement. Aluminum: If money is no object.

https://www.reliablesteam.com/new/boats.php?iid=BT05
Image

Re: boat plans

Posted: Mon Jan 17, 2022 4:57 am
by barts
DetroiTug wrote:
Sun Jan 16, 2022 3:51 pm
Steel: 1/4x2 frames, 3/8 x3 keel, 12 GA on the bottom 14 GA on the sides. Need a plasma arc to cut the skin. Need to calculate weight displacement.
You'll want some thin bar in there for the chines; you'll also need the same for some deck framing and stringers. I'd suggest pipe for the deck/side joint as that takes punishment.
She would end up weighing order 1000 lbs for the bare hull, I'd guess. I'd suggest lighter scantlings and plating for this hull shape; some 1/8" tee section would work well for frames, and having the framing closer to the size of the plating will help reduce plating distortion.

The same hull in stitch and glue w/ okume plywood and epoxy would weigh less than half as much, I'd think.

I'd love a steel boat, but there some some definite tradeoffs below 25-30 feet in length, and smaller vessels definitely need careful attention in salt water since the plating and framing is necessarily lighter. There are lots of small Dutch steel boats, but they tend to use forming rollers to build with dished plates. For example, examine the pram in this picture as opposed to the skiff.

https://i0.wp.com/intheboatshed.net/wp- ... -skiff.JPG

Here's a video of Bruce Hepler's Skedaddle, which of steel construction at Clear Lake, CA. https://youtu.be/GU5gamzIZ4o

- Bart

Re: boat plans

Posted: Tue Jan 18, 2022 3:46 am
by Lopez Mike
I love the lines of Panatella but I have talked to people who steamed her and they said that the boat was amazingly unstable in roll and sensitive to crew placement. Needed more beam.

I have no idea about your power plant. Size? Power? Weight?

I am very happy with the hull I have built. Same lines as Iona. http://steamlaunchiona.blogspot.com/201 ... esign.html

Do NOT be panicked when you look at Steve's workmanship and execution of this design. Steve, by his own admission, is a fanatic. My boat will never be allowed to tie up next to Iona for fear that Spiffy would self combust from shame. Back off twenty feet and you might not notice the difference (much).

But I have about one third the hours and about as big a difference in investment. Iona will attract aficionados and awe. I will be loading up boatload after boatload of naive land lubbers who are convinced that they are embarking in the African Queen and, "By the way. Where is Katherine Hepburn?"

If you want to build a hull that you can get in the water in a relatively short time, do some looking for a used hull. Next, the path of using a sailboat hull and then a stitch and glue plywood hull. Everything will take twice as long as you imagine and cost more. Get used to it. I haven't just yet.

Mike

Re: boat plans

Posted: Tue Jan 18, 2022 5:14 pm
by Kelly Anderson
If you plan in building in steel, I suggest that you pick up copies of these books, Steel Boat Building, and The Nature of Boats. Note that Dave Gerr says that steel doesn't begin to have a weight advantage over other materials until length reaches about 90'.

Also keep in mind that modern steels don't have nearly the corrosion resistance of the steel made back in the steam era. As an example, I replaced the cylinder jacket on a steam locomotive at my former place of employment in the 1990's. The old jacket dated from at least the 1940's, because it still carried dents from a wreck at that time. The replacement was 18 gage mild steel sheet, primed on both sides. In service, it is constantly exposed to high humidity from the cylinder cocks. It rusted through in four years. Since that experience, all sheet metal on the locomotives was replaced with stainless steel, so we weren't constantly replacing it.

I echo the other posters, shop for a used hull. You will be happy you did (or at least less unhappy).

Re: boat plans

Posted: Tue Jan 18, 2022 8:44 pm
by TahoeSteam
Panatella that have been scaled up to 25 or even 30 feet are very stable and push very easily. The 20foot version is just a bit petite with it's designed width.