Converting a Electric motor Qboat to a Sailboat.

[Projectnick]

Thank you for the response Skyak. I think so too. My hull is not made for sailing in the first place. My keel is not that deep so i am thinking i might end up with a thing like this in the video, which is a wingsail with stabilizer, as a best case. This even needs a good keel.
Instrument donot have to be upright and sail and keel wont interfere operation. NO draft limits.
The long term goal of this project is to make this boat autonomous with a remote feedback and onboard feedback control system.
I basically have to design a sail for the already existing hull.
I think mine would look something like this during the process.

http://www.youtube.com/watch?v=7c6huxhtTMY

If the boat cant be sail power, i need to recommend the changes in the hull shape and sail and power system that need to be made for a hull similar to this to be a sailboat.

 

[sharpii2]

Hello everyone,
I have a Qboat which is Electric powered and i want to put a sail power on it. I am a Naval Arch Student and I don't see many materials online on conversions. I have been reading stuff about it and I am not sure how professionals choose the shape of the sail, number of sail, and area of sail. I would really love some professional advice.

This is my boat
http://www.oceanscience.com/pdf/Q-Boat 1 Spec Sheet.pdf

this boat has a keel and rudder too.

A number of things to think about, projectnick.

1.) you want a sail that gives you the least heeling moment per drive, not necessarily one with the best lift/drag ratio,
2.) you need a sail that can feather without ripping itself to pieces. This may be more important than its actual efficiency,
3.) you need a system that can automatically 'dump' the sheet line tension in a gust, then reset it when the gust ends. This way, the boat doesn't have to change course to avoid capsizing,
4.) you need adequate lateral and rudder area to make decent windward progress and control the boat, and
5.) you need enough ultimate stability to right the boat from a knock down of at least 90 deg. Your ballast keel calculations should at least start with that number. (keep in mind that adding a keel that, in total, weighs more than it displaces will subtract from the free board of your boat)

Assuming the all up weight of the boat will be 120 lbs (54.6 kg), 24 sf (2.23 sm) is a good starting point for your Sail Area (SA).

A low aspect ratio wing sail might work as it meets condition 2.) quite nicely, and can go a long way toward meeting condition 3.). I say low aspect ratio to keep the height of the rig per SA within reason. Keep in mind that a new rig, that is twice as tall as an old one, must weigh half as much, to have the same Vertical Center of Gravity (VCG).

If it were my boat, I'd go with a Rogallo lateen sail (like you see on a Sunfish(r) sail board. It would have a 7.25 ft (2.21 m) boom and a 7.25 ft yard. The yard would be st at a 4:1 pitch (rise over run). All the spars would be made of material that floats.

A maximum of two winches would be required. One to raise and lower the sail and one to control the sheet line.

 

[Projectnick]

Thank you very much sharpii2 for the response. I think you meant to say about 7m^2 SA for 120 lb sunfish. By the way, by yard, do you mean slanting distance in the height direction?

 

[DCockey]

Since the long-term goal is an autonomous sailboat I assume the mission will be open ocean or other large body of water and the duration could be quite long. If that is the case then I'd:

1) Make the boat self-righting from any position. This can require sufficient topsides buoyancy in addition to sufficiently deep ballast. Is the current boat self-righting from any position?

2) Consider not having a "a system that can automatically 'dump' the sheet line tension in a gust, then reset it when the gust ends." That would be require controls and considerably increase power expenditure. It would be simpler to accept heeling and course deviation.

 

[DCockey]

Harbor Wing Technologies has worked on autonomous sailboats with wing sails. There website is http://www.harborwingtech.com/ though it doesn't appear to have been updated since 2010.

 

[sharpii2]

Thank you very much sharpii2 for the response. I think you meant to say about 7m^2 SA for 120 lb sunfish. By the way, by yard, do you mean slanting distance in the height direction?

No. I meant 2.23 sm for your boat.

Rise over run is a roofing term to describe the slope of a roof. I use it so I don't have to deal with a lot of angle math. I mean the yard is joined to the boom at the front end of the boom and slopes back one foot for every four feet of height.

 

[sharpii2]

Since the long-term goal is an autonomous sailboat I assume the mission will be open ocean or other large body of water and the duration could be quite long. If that is the case then I'd:

1) Make the boat self-righting from any position. This can require sufficient topsides buoyancy in addition to sufficiently deep ballast. Is the current boat self-righting from any position?

2) Consider not having a "a system that can automatically 'dump' the sheet line tension in a gust, then reset it when the gust ends." That would be require controls and considerably increase power expenditure. It would be simpler to accept heeling and course deviation.

It may be possible to make a system that can do this with springs, cams and maybe bunji cords, so it would be completely automatic, and not require one watt of additional power to operate.

That's what I meant.

 

[Projectnick]

Thank you all!!
How do you go about the design validation of sail boat? Is the VPP good enough validation technique for the sailboat design? I have not been able to get good book on validation by VPP. Can you suggest anything on it?

 

[DCockey]

Thank you all!!
How do you go about the design validation of sail boat? Is the VPP good enough validation technique for the sailboat design? I have not been able to get good book on validation by VPP. Can you suggest anything on it?

ORC VPP:
http://www.orc.org/index.asp?id=21
http://www.orc.org/rules/ORC VPP Documentation 2013.pdf
http://www.orc.org/index.asp?id=41 See if you school has a copy.

 

[Projectnick]

Thanks Dcockey,
That program cost a lot of money apparently, I think best way for me is to work out it out in excel, unless i find some pirated VPP packages.