Electric Leisure Boat Design II

There are a few requirements not nailed down here.
1.) Maximum length,
2.) Typical payload (people and things the boat must carry),
3.) maximum Beam, and
4.) How people are going to get on and off it.

A two person boat, for example, should have a payload of 400 lbs (182 kg) give or take. Just add 200 lbs (182 kg) for each person the boat is to carry.

Then, to be really optimistic, multiply this product by 1.50.

If you are not so optimistic, you may go as high as 2.0.

So the total weight (displacement) of a two person boat can be between 600 to 800 lbs (273 kg to 364 kg). This includes the weight of the boat, battery and motor.

I would also assume the two people on board will want to sit side by side. This will require a Beam of atleast 4 ft (1.22 m).

To get a Displacement/Length ratio of about 150, the Waterline would have to be close to 13 ft (4.0 m) long. The boat could be the same length or a little longer.

I can easily imagine a boat that looks a lot like a Sneakeasy with these two dimensions. It could easily have a wind screen and a steering wheel too.

 

That's quite a project. There is a glass or plastic bottomed boat to rent which I will try next, and maybe post pictures. There are some boats where the hull has a glass viewing panel, quite spectacular.

 

Electric boats are a good bet, actually I think their time has come. There is even an electric ferry in India that I came across.

Even more inspiring is this ad-hoc solar boat. With a few more panels, something the 10ft long will have a lot of space to put those things. Peter Sripol from RC aircraft fame built a solar powered boat also. Pretty impressive.

The Kayak I rented had some holes right through it 'that's ok' and it did not sink. Flotation could be achieved with empty plastic water bottles quite cheaply I think, I am all for flotation.

On the subject of safety, boats seem to be safer than single engined airplanes - when the engine stops, or you run out of fuel and the engine stops. Running into the path of a large vessel such as a kayak running in front of a ferry is survivable, however, not recommended. There is some information on boating accidents:

In 2020, the Coast Guard counted 5,265 accidents that involved 767 deaths, 3,191 injuries and approximately $62.5 million dollars of damage to property as a result of recreational boating accidents.

• • The fatality rate was 6.5 deaths per 100,000 registered recreational vessels.This rate represents a 25% increase from the 2019 fatality rate of 5.2 deaths per 100,000 registered recreational vessels.
  • Compared to 2019, the number of accidents increased 26.3%, the number of deaths increased 25.1%, and the number of injuries increased 24.7%.
• Where cause of death was known, 75% of fatal boating accident victims drowned. Of those drowning victims with reported life jacket usage, 86% were not wearing a lifejacket.
• Where length was known, eight out of every ten boaters who drowned were using vessels less than 21 feet in length.
• Alcohol use is the leading known contributing factor in fatal boating accidents; where the primary cause was known, it was listed as the leading factor in 18% of deaths.

 

That is inspiring, thanks, I had seen it before. That's an awful lot of work to do for a boat, I might make mine out of sheet metal in three removable sections. I can't see myself working with GRP, plywood maybe. The motors are interesting, 1 kW motors tend to be expensive, these ones seem to be hobby grade, and two of them could also offer differential thrust. The seat could be lower like a racing boat, otherwise he gets upto quite a speed for that design. I don't see any batteries.

 

The seasonality factor is a big one, I missed that. Here in the Maldives this particular location has been badly hit by a huge drop in tourists from China, and several people here have mentioned it. I guess it is wait and see.

I walked halfway down Phase 2 looking for a jetty, but that was a bit further. Maybe they offer boat rides. Apparently fishing has also taken a hit. A contact I have may arrange for a boat ride soon.

Meanwhile here are some images I took today on my walk.

 

Some things to consider: ship construction https://www.britannica.com/technology/ship-construction

10ft in length, 2 persons side by side, dual 1000W electric motors and two 12V lead acid batteries for a start.
Switched power to run off left battery, right battery or both. On/off only for a start, saving controller costs.

 

His batteries are in that metal box he placed in front of the seat. his electric builds are like a big model boat, but they are boats since they can carry a passenger. his disclaimer are the vids are for entertainment purposes only.

 

So I am continuing to gather information, and re-reading this thread from the beginning. I am also coming to the grim realization that boat ownership may be many years in the future...

Vision of future boating - design competition https://www.boatdesign.net/threads/vision-of-future-boating-design-competition.38639/

The final design, given the low powered electric power, will probably be an electric catamaran. That being the case, I looked up some antique boats for some inspiration, and what I found really floored me. The boats are unimaginably beautiful. Someone suggested the Sneakeasy, these boats are also the same vintage, more or less.

Have a look at the Antique Boat Center

The History of Chris Craft

Antique boats for sale

 

Ok so to recap: forget the speedboat or planing hull. In order to make the most of the modest power, it will need to be a catamaran. That is fine with my but placing the seats and steering lower down will be an unusual step.

Nature of Boats the book is yet to arrive.

The Sol Gato is a good boat. Need to look at it again. Thanks to rnlock for doing some estimates.

A converted pedal boat is not a good idea- highly inefficient.

The example electric boat videos were useful, found some more that illustrate the nuances of lead-acid battery controllers, electric outboards and costs, as well as solar panels, amperage at certain speeds and so on.

The boat has to be foldable or nestable or otherwise transportable in a car or van. That is being explored in another thread.

Next : specifications, 3D concept of the design, and electric motor arrangement, costs.

 

Design

2 Seat electric powered boat prototype
Length: 10 ft (3.0 m)
Beam: 4 ft (1.2 m)
Accommodation: 2 persons.
Motor: 1 kW
Battery: 2 x 12V Lead Acid battery, 1 spare battery
Power Control: On/Off switch between off, 12 or 24 Volts (2 speed)
Spare battery has to be manually connected
Propeller protection cage to protect propeller when beaching
Roll -on wheels under rear of catamaran
Steering through a series of connected aluminium rods connected to rudder
Sponsons and deck are can be dismantled and carried in a vehicle
Aluminium sponsons filled with flotation cells (plastic bottles)
Deck and enclosure aluminium or canvas on metal frame.
Range: 2 miles
Cruising speed: 5 knots

Costs to build including motor and batteries: $800

The curved version may be more expensive to build

 

On second thoughts, modifying a dinghy hull will cost much less.

Here we go.

Fiberglass Boat, Dinghy, Tender. Dingy Length 310cm Or 10ft Good Condition. for sale from Australia https://boats-from-au.com/not-specified/fiberglass-boat-dinghy-tender-dingy-length-310cm-or-10ft-good-condition-168966

 

These seem to be quite common, made out of plastic, mostly, and every boat seems to have one attached. Given the price of the complete hull with the transom suitable for a motor, the dinghy could be modified with some decking and the electric motor and battery - very little construction is required. As a prototype, it's good, as a basis for the next boat.

I wonder if anyone has tried, and is it made out of the dreaded PVC?

Buy Small Plastic Boats Online | Canada & USA | Backwater Boats https://plasticboats.com/shop/

 

Your design made tremendous progress over the last couple of weeks!
I sent you a PM with information you might find helpful.

 

Thanks to all at boatdesign.net, really a very kind forum. Improvements are due to the advice I have received from this forum, mainly. When it came to counting the cost I quickly became convinced that building the hull was not the way to go. Hulls do need a pointy end to slip through the water I realize.

For inspiration for small boats, I look here. Most are overpowered, mine will be politely called a cruiser, at least while testing.

My favorites are, from the video: #14 and the Jim Boats 6.5. It's fast enough but could be a bit larger, which would slow it down more. The Mini Tugboat is a great toy to take the kids out in, could even be electric at that speed.

I could pull a 20 metre long barge with solar cells that will give me 30kw.

"Flotation" Thanks for the PM

 

Met with the managers of a beach sports unit here, apparently only jet skis are permitted in our little lagoon or reef and that only at low tide. That rules out propellers. There are some private PWC parked here though, that is an opportunity to park one here if you know what I mean.

Since importing is so expensive, how about using a jet ski hull and turning it into an electric boat? Or even an engine powered boat?

Oh how about have a lark for $700?

HUP Jet Lark 1984 for sale for $700 https://boats-from-usa.com/not-specified/hup-jet-lark-7695

Here are two conversions, the second one is a fast one, but I think I hear the prop changing pitch which may be cavitation, which is not good, not good. Maybe.

Jet Ski converted into two person small boat

Boat to jet boat conversion