Power requirement for 10m canoe

I'm trying to find out the power requirements needed to propel a boat similar to this design loaded with 2.5 tonnes reaching a top speed of 11 knots. It will be used on the river with minimal current considerations.

 

The design did not load.

 

FAO Fisheries & Aquaculture https://www.fao.org/fishery/en/vesseldesign/cey-5

 

About 35 or 40 hp

 

That is 7.1 m, or about 23 feet. The "hull speed" is about 6.2 knots. At 11 knots you would need to be planing, which this kind of hull is not designed for. What is the purpose of the boat?

 

It is for an eco-tourism lodge in rural Ecuador. They're asking for a fiberglass canoe about 10 meters in length with room for 10 passengers that can reach a top speed of 11 knots. My team and I are all engineers, but have no background in boats. Any help is appreciated.

Edit: They are also, ideally using an electric motor, hence the thread.

 

That is not a canoe by any definition. The request is unrealistic. The laws of physics are immutable. If you have no background on boats, this job may be beyond your scope. Do you need to buy a complete boat or a design and construction tech support?

 

I agree, this is very challenging. Per another member's suggestion, I've been using this website's design considerations:

FAO Fisheries & Aquaculture https://www.fao.org/fishery/en/vesseldesign/search?page=1&q=canoe#search

It shows canoes ranging up to 15+ meters in length. The power requirements, I agree, are absurd. They've been operating with 4-stroke engines in the past, and electric is the most ideal case scenario. I'm just seeing what I can to make it work for them.

The boat can be fabricated with fiberglass onsite. If we could use one of the free sourced designs from the site I listed, that is the most ideal case.

 

The largest canoe they show is 15m (49.2 feet) and it has a service speed of 8knots with a 40HP gas engine. It is also made of wood. Building the boat on site is a bad idea. Who is going to train workers and supervise the construction. Also, shipping materials to the site may be problematic. Even if you use a free design, it will require shipwrights/boatbuilders. You are way over your head on this project. Either you learn boat design and boat construction first, or farm out the job to qualified persons.

 

They have a boat builder within the community that fabricates boats already

 

What are they contracting you to do?

 

Come up with a design for a 10m canoe style boat that would seat 10 people and reach a max speed of 11 knots ideally using an outboard, electric engine. It would have to run for 2 hrs ferrying people about 2 km up and down the Amazon river.

 

It can't be done. I understand the marketing "eco-tourism" name for increasing sales, hence an electric motor. However, the SOR makes no sense. They are stating constraints that can't be met. To start with, a boat built locally is most likely going to be rather heavy. For the intended use, a somewhat overbuilt hull is a good thing anyway, but will be slower and require more power for the same speed. 6 knots would be realistic. Electric systems need the batteries recharged. How is that going to be accomplished? Also, electric systems are heavy compared to gasoline or diesel. Once more, you are over your head. The question you ask are basic, which means you are really far from qualified to design and build the boat including all the support systems. Further, consider the maintenance and repair that has to be included.

 

They have photovoltaic power sources for the batteries on location. I appreciate that this is a difficult undertaking, but iterating time and time again that I am in over my head does not absolve me of the responsibility of following through, it just makes me feel worse in the interim, so thanks for that.

My aim here is to confirm that electric is unfeasible and to have a good justification to bring to the user.

 

It is not really difficult as a design. In fact, there are many available designs that could fit the purpose. However, look up "design spiral". Start by studying the operating conditions. For example, depth of water, rocky shoals, floating debris, overhead obstructions, etc. That is the first step. If I understand correctly, you have to comply with a contract to design and build a fleet of canoes? To build a fiberglass hull, first you build a plug. Secondly, you build a mold off the plug. Then you build hulls. The deck, seats and other parts go through the same process. The plugs and mold need to be accurate enough that the parts will fit properly. I think your safest route is to hire a knowledgeable person to do the job. You can probably make a profit after paying an employee.