Thruster size for 415

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   Yes, the ring is sandwiched as you describe.  I used thickened epoxy to glue it to the hull first, then the rest of the interfaces use Sika as Jet Thruster recommended.There is enough space for 2x 75Ah batteries on either side, so primary power cables will be nice and short.
I also faired the outside fittings (especially the intake) to make them relatively hydrodynamic.
I used 25 degree nozzles that fit pretty well.  I mounted them about 3 cm below the real waterline (I used the scum line as a guide).  Apparently they actually work better above the waterline but then you look like a fire boat.  Getting them 7 cm below the waterline was putting them so low that in inner fittings wouldn’t fit.
The inner fittings actually have keys that align them with the nozzle.  Because you drill on a relatively large angle and the hull thickness varies in this area, I found that grinding off these guides so the inner fitting was free to rotate allowed for a much better fit to the inside of the hull.  I ended up using one thin spacer as well, so I left that with the guides so it didn’t spin when tightening the restraining nut.
The hull is very thick in this area, over 4 cm.  

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SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 23 May 2022 at 13:28
	Yes, the ring is sandwiched as you describe. I used thickened epoxy to glue it to the hull first, then the rest of the interfaces use Sika as Jet Thruster recommended. There is enough space for 2x 75Ah batteries on either side, so primary power cables will be nice and short. I also faired the outside fittings (especially the intake) to make them relatively hydrodynamic. I used 25 degree nozzles that fit pretty well. I mounted them about 3 cm below the real waterline (I used the scum line as a guide). Apparently they actually work better above the waterline but then you look like a fire boat. Getting them 7 cm below the waterline was putting them so low that in inner fittings wouldn’t fit. The inner fittings actually have keys that align them with the nozzle. Because you drill on a relatively large angle and the hull thickness varies in this area, I found that grinding off these guides so the inner fitting was free to rotate allowed for a much better fit to the inside of the hull. I ended up using one thin spacer as well, so I left that with the guides so it didn’t spin when tightening the restraining nut. The hull is very thick in this area, over 4 cm.

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 29 May 2022 at 20:22
	All fits with batteries!

Iris Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 03 July 2021 Location: Croatia Status: Offline Points: 38	Post Options Post Reply Quote Iris Report Post Thanks(0) Quote Reply Posted: 09 October 2023 at 12:54
	Hi, couple more questions,am planning to fit the same this winter. How much clearance is there from the top of the pump to the underside of the bunk boards, I was hoping to mount it off the centreline, have the outlet pointing to port(or Starboard)with a 90deg pointing forward, hopefully giving enough room to mount valves. Possibly mounting batteries in compartment but if not poss aft of the water tank. Do you have many pics of the installation that you could direct message me or email please ?t.condick@gmail.com Thanks

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 10 October 2023 at 14:51
	The top of the pump is pretty close to the underside of the bunk boards - about 1cm. The hull has a pretty decent slope at that point, so moving it to one side or the other would cause issues. If you're really driven to make it work that way I presume you could raise the bed level to make it clear. Obviously I decided to forgo the valves for the reasons i previously posted. One other option is to stagger the output nozzles (put one further forward and one slightly aft) so that you can fit the nozzle valves. The other consideration is the number of pipe bends - every 90 degree significantly drops your output flow & pressure. Futhermore, there isn't a lot of options on the battery placement - the factory install puts them aft of the tank where the water pump sits. Its so tight that you have to remove the tank to remove the batteries. So everything is a trade, I decided that the lack of valves was better than a more convoluted install with more joints and bends. Happy to share whatever i have. I actually built a 3D cad model with parts provided by Jet Thruster and took a long time and tried many differently layouts to find something that fit. I can provide screenshots of that as well.

Iris Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 03 July 2021 Location: Croatia Status: Offline Points: 38	Post Options Post Reply Quote Iris Report Post Thanks(0) Quote Reply Posted: 10 October 2023 at 17:30
	The CAD option pics would be good. Looking under the boat it looks like in the centre position where you’ve mounted the pump it has a V in the hull, did this cause a problem mounting the intake as it’s not flat ,is it?

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 10 October 2023 at 19:28
	Yes, but it's not too bad. Basically I made a flanged sleeve that slid tightly into the ring upon which the pump sits. This assured that the outer flange and the inner ring were parallel, so that when you tighten up on the threaded inlet flange, it loaded up evenly around the entire contact area. I then used an epoxy fairing compound to fill the gap on either side and fair it smoothly to the shape of the hull. I'm currently traveling on business, when i get home I can post some of the 3D models that will better illustrate what I'm talking about.

Iris Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 03 July 2021 Location: Croatia Status: Offline Points: 38	Post Options Post Reply Quote Iris Report Post Thanks(0) Quote Reply Posted: 12 December 2023 at 17:52
	I’m currently in the pre-order communication with Holland Marine and am hoping to take the boat out and fit the nozzles at the same time so won’t have opportunity to measure nozzle angle before ordering.I was assuming they would be the 25 degree as with yours, but they have said that previous 415s have ordered 35 degrees. Was the angle you measured between 25&35 or do you think it’s because others have mounted the nozzles further back on the hull?

SimonGH Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 08 September 2021 Location: CT Status: Offline Points: 124	Post Options Post Reply Quote SimonGH Report Post Thanks(0) Quote Reply Posted: 13 December 2023 at 23:29
	I think it's because they've mounted further back. it's pretty vertical near the bow, and as close to the waterline as i mounted them (i'm definitely not following their depth guidance, and if my bow water tank is low they are partially above the waterline). They were pretty good about shipping multiple nozzles and then just taking the un-used ones in return, so perhaps that's the way to go?

Fendant Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 03 November 2012 Location: Switzerland Status: Offline Points: 1671	Post Options Post Reply Quote Fendant Report Post Thanks(0) Quote Reply Posted: 14 December 2023 at 06:34
	Simon, I saw that you have not fitted the safety valves behind the through hull fittings, Do the insurances in the US accept this? Best Regards Frank Edited by Fendant - 14 December 2023 at 06:35
	Frank

Iris Members Profile Send Private Message Find Members Posts Add to Buddy List Lieutenant Joined: 03 July 2021 Location: Croatia Status: Offline Points: 38	Post Options Post Reply Quote Iris Report Post Thanks(0) Quote Reply Posted: 14 December 2023 at 08:33
	Thanks , regarding nozzle angle, I’ve already mentioned that to HM so I think that’s exactly what I’m going to do. In partial answer to Frank, I think he addresses this earlier in the thread. I’m probably going to do it slightly differently as I have made my bunk bigger I think I have room aft of the tank and bulkhead under the bunk for a horizontal motor . Simon has done a very neat job but I don’t have the CAD skills or access to 3D printers etc so am giving myself a bit of flex, but as I say I have a larger overhang to tuck it under. Tony



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