I'm terrified.. What should be the diameter gap for pod drive housing?

The sealant manufacturer generally will provide the margins the glues are designed for..

 

I finally got around to see the manufacturers youtube. The lower unit has a flange around the shaft that is bolted to the hull with 6 bolts. Wich means sealing isn't happening in the hole, it's happening on the flange. The OP has shown us the wrong pictures, the upper part doesn't really matter with this particular subject.

To answer the question, this is like any other flanged penetration (trough hulls for example), the hole is just big enough to slip the part in with a chamfered edge towards the flange. When the flange is torqued down the sealant in the chamfer acts as an O-ring. In a submerged application like this, with properly mated surfaces there won't be any problems with differential expansion and the job will last decades.

 

?
Would you be kind enough to paste the yt link?

 

Electric propulsion POD boat - POD 3.0 - Rim Drive Technology https://rimdrivetechnology.nl/product/pod-3-0/

 

Ideal Flettner drive.

 

Im curious how they solve the problem of cable twisting . I use some polish made microscope and geniuses have put the cables into base, while head is rotary 360deg. Once we broke the cables because of twisting.
edit :

rotation 300 deg C

 

What you talking about ?

 

I am talking about this:

 

The steerable version has the same thing, a plate connected to the packing gland, and this plate is screwed to the hull.
That's because of torque, the thrust applied by the prop must be transferred to the hull. This is like installing a spade rudder, the tube with the bearings must be rigidly connected to the hull.
Anyway, a short conversation with the manufacturer will clear his fears.

 

Is there any thrust ?
Mounting plate (optional) , waterproof seal (optional , we sell it mostly to the U-boots ) .

Maybe OP show us more photos. For me rotational version have sealing inside this massive sleeve that is sealed to the hull by 5200.

 

They didn't exactly go overboard in designing the mounting system. In a way I can understand that, each boat is different and professionals won't have a problem finding the right solutions. If your bottom is only a few millimeters thick, or V shaped or rounded you need a different solution then a 50mm perfectly flat bottom. A steel boat could just have the gland welded in, some glass boats would need an additional tube with brackets, etc.

On the other hand they do force the installers hand by their design choices. Take for example the setscrew retaining the lipseal. It's presence almost mandates the sealing gland beeing exposed underwater, you can't do a flush fit without going to some engineering acrobatics. Replacing the lipseal (it's a wear item) after the inbus head setscrew was antifouled will be a joy. There are of course ways to fix that even after the fact, but it's regrettable to have to do it.
I have no ideea if the shaft is rigid enough to allow a flexible sealant to work without any additional mechanical fixing, and where the upper hp limit is for it.

I am sure there will be product improvements in future iterations after customer response comes in.

 

Yes . Probably rotational version have mounting plate and seal optional , in the case of outboard like mount. And this rotational mounting plate has nothing to do with the fixed pod . Rotary mounting plate that transfer thrust should have a bearing otherwise it makes no sense .