Diy dpv

[shenzhen]

We made it from a trolling motor 12V 15A 18 lbr.
The shaft tightened by ceramic seal.
Powered by three SLA battery 12V 7Ah.
Housing is a PVC pipe 200mm.

 

[lucca brassi]

Great ! How work in water ? Stability (horizontal postition how is trimmed - neutral buoyncy) ? I have same idea to made DPV in similar way .

 

[shenzhen]

Now I see, it's so easy to build you own thruster
There's really no problem to made it in few days. Stability and neutral buoyancy are the smallest problem, trust me.

At first you should decide what will be the weight without pipe. For example, my weight is: 3 battery (2.6+2.6+2.6=7.8kg), motor (2.6kg), motor fixing (0.6kg), propeller's pipe with handle (0.7kg), switch + wires + power control (0.5kg) and of course 2 thick caps for pipe (1.2kg) = 13.2kg.

Now you can chose the pipe material, PVC, for example. The specific gravity (density) of PVC is about 1.4. So, we can calculate pipe running centimeter weight and running centimeter buoyancy for some diameter and wall thickness. I would prefer 9mm thickness but found 4mm only. My pipe is 200mm diameter and has 0.347kg running centimeter buoyancy, so for 13.2kg I need about 38 centimeters of this pipe. So I cut 39
I think it's a good idea to make one cap non-removable and glue it.
For another one I bought 2 o-rings.
The batteries are lying one by one on the bottom cap and screwed on.

It was too much buoyancy and I added some weight, until became a little bit positive buoyancy, then I found the good position for additional weight to become horizontal stability and screwed it on.
That's all.
A little video will be later.
View attachment 135953View attachment 135954View attachment 135951View attachment 135952

---------- Post Merged at 04:10 PM ---------- Previous Post was at 09:40 AM ----------

 

[DepthCharge]

We made it from a trolling motor 12V 15A 18 lbr.
The shaft tightened by ceramic seal.
Powered by three SLA battery 12V 7Ah.
Housing is a PVC pipe 200mm.
View attachment 135853View attachment 135854View attachment 135855View attachment 135856

Two questions if I may. What is the thrust of the unit? What do you mean by a ceramic seal?
Thanks,
John

 

[ktomlinson]

Very nice! I look forward to seeing the video and learning more about the project.

 

[shenzhen]

Two questions if I may. What is the thrust of the unit? What do you mean by a ceramic seal?
Thanks,
John

I think it's a tradition to evaluate the thrust in pounds but we can convert lb into kilogram
Trolling motors have the standard thrust step: 18 lb (8 kg), 24 lb (10 kg), 30 lb (13 kg), etc.
I've got the smallest (cheapest) motor 18 lb or 8 kilogram of thrust, like in a children toy scooter. It's... slowly
I recommend to buy 30 lb or more.

About ceramic... Trolling motor shaft tighten by 2 o-rings only and can leak on xx meters depth, cause it not for diving. You can increase its depth by ceramic seal. Most of motors have a place on the housing to mount mechanical shaft seal).
Ceramic has very big hardness, 2 hight polished ceramic washers placed face to face and pushed with hight pressure can rotate without abrasion and will never wear out. These 2 hight polished ceramic washers will seal your shaft up to 5-15 bar (depend on supplier).

 

[SupSonDiver]

Any chance for a full schematics, like a section cut across the elements going into this DPV? I am giddy & interested. I lack a bit of knowledge in the department of powering & trolls but it will make sense very easy once I get a glimpse of the sectional layout of the dpv

 

[Sakoboy]

I love it... I'm planning on building one of these over the winter and your pictures and information will be a great help.

 

[shenzhen]

When it was a boat motor it rode 4,5 km/h.
[video=youtube;9oRKErAnvgg]http://www.youtube.com/watch?v=9oRKErAnvgg[/video]

---------- Post Merged at 03:59 PM ---------- Previous Post was at 03:29 PM ----------

Now it can 1 km/h only, but I love it!
[video=youtube;UgWIK6eWHUY]http://www.youtube.com/watch?v=UgWIK6eWHUY&feature=youtu.be[/video]
to be continued...

 

[DepthCharge]

I think it's a tradition to evaluate the thrust in pounds but we can convert lb into kilogram
Trolling motors have the standard thrust step: 18 lb (8 kg), 24 lb (10 kg), 30 lb (13 kg), etc.
I've got the smallest (cheapest) motor 18 lb or 8 kilogram of thrust, like in a children toy scooter. It's... slowly
I recommend to buy 30 lb or more.

About ceramic... Trolling motor shaft tighten by 2 o-rings only and can leak on xx meters depth, cause it not for diving. You can increase its depth by ceramic seal. Most of motors have a place on the housing to mount mechanical shaft seal).
Ceramic has very big hardness, 2 hight polished ceramic washers placed face to face and pushed with hight pressure can rotate without abrasion and will never wear out. These 2 hight polished ceramic washers will seal your shaft up to 5-15 bar (depend on supplier).
View attachment 136040

Thanks for the info.........actually found quite a bit about ceramic seals...........look very promising.
Thanks again,
John