DON'T USE EXPANDING FOAM UNDER ANY CIRCUMSTANCES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Expanding foam will continue expanding every time it gets warm and will, eventually, blow the boat apart. I would get some of the blue insulation foam, cut it into blocks and drop it in between the frames. Now, for your other things you received:

• The rudder bracket could be an issue, due to it's length. It will make the boat act like it's longer than it really is
• Servo mount would be fine if you install it under the cowl and point the arm down. What servo are you going to use for the rudder?
• Do you really need that big of motor? That looks like one that would be used in an electric 1/8th scale

It's specific boat building foam, closed cell etc, the same stuff that Scott Myers uses.

Yeah I just realised they sent me the wrong rudder so it'll have to go back.
This is the servo:
https://cimg5.ibsrv.net/gimg/www.rcu...783ac46ec7.jpg

Yes it's big enough to run a 1/8th, might have to build one after this ;)
This is what he suggested so I just went with it. Hopefully not overpowered but I could dial it back with the ESC?

I'll have to give Scott a yell since I've never seen good things happen with the expanding foams.

That would be awesome HJ!

Got a reply to my email about using the foam, kind of the answer I expected. Here's what he said:
My video is the best explanation.
Yes the expanding foam will blow things apart if you try to use it in a sealed area, which would be remarkably foolish!
Please watch my video as there is so much more to it. You'll find your answers there.
Note that you must use the "2lb" foam and NOT "6lb"

Scott Meyers
Reckless Adventurer and General Bum

M5 Performance Hydroplanes
https://youtube.com/user/matinco2

https://m.facebook.com/M5-Performanc...?ref=bookmarks

I don't have a Facebook account so I couldn't open the video so I don't know what it shows
HJ

Sweet, thanks for looking into it for me!! I think those links just go to his main youtube and Facebook pages.

Glad I mentioned it ha!!

Currently trying to find some good advice on motors etc if this one is too big, no point having someone big and heavy if it’s not required.

Okay, he sent me the link to the video and, if you follow his directions, you can get away with using the two part foam as shown in this video:
Personally, I won't use it because, while he says it makes the boat stronger and could be right about that, it also makes repairs harder since you have to clean the seal off to replace parts. Then again, that's just me and I like to keep things simple.

Thanks HJ, yeah that's where I got the idea :)

I've been looking at the rules for various 1/10 hydro competitions around the USA and it looks like they mainly use 4S. Not sure what to do now but will keep researching.

My boat is 34" which is right on the line between a P class boat and a Q class boat. It's an inch short to be considered Q class, which allows for the electronics I have. So I think I'm going to stick with it for now :)

Look at it this way, if it's not a legal boat to race, you can always build another one that is "Q" legal taking what you learned and apply it to the next boat

Totally. The specs here in Aus are much more simple anyway, and simply state that you conform to the cell count and says nothing about hull sizes. So there's 2 classes you can race in, EB electric class and hydro boats, and EB electric Hydro Sport class (the only difference being that the second one is for scale boats). I'm not sure how many people race these classes here but it's good to know it fits somewhere.

You're right I'll have a lot more experience for the next boat so might seek out a more well represented class for that one.

FINALLY, I was able to work on my boats today. I'll be starting a thread on my Pak build in the nitro forum probably next weekend so, BEWARE!!!! YOU HAVE BEEN WARNED!!!!! ;)

Haha!

Looking forward to it!!!

Okay, but just don't be surprised if it's not what you expect since, as I said, Scott and I do things differently

Looking forward to seeing the different ideas/processes.

What's your opinion on preparing for paint, in doing that last layer of prep? I an still see the grain in my undercoat, would you sand/undercoat/sand repeat until it's all smooth or use another method?

Epoxy seal, sand, prime, sand, prime with a different color, sand again to make sure there are no low spots, shoot paint

Sweet. I was having trouble sanding my primer but I think seeing it's getting colder here it may not have been dry enough. Will try again tomrorow.

The big thing with what I posted is to make sure you don't sand through the epoxy in the first step. If you do, you will need to re-coat the areas you sanded through and re-sand those so you have a continuous layer of epoxy to shoot the primer on. If the epoxy has gaps, the wood grain will show through the paint in any areas where epoxy was sanded through. Been there, seen that

Thanks HJ. The thing I'm painting for now is the model for the fibreglass cowl so it doesn't need epoxy, that's why I'm seeing the wood grain.

Do you use fiberglass inside or out or just brushed epoxy?

You won't find fiberglass in any of my wood hulls. As far as I'm concerned, if the boat is properly built, it's just added weight. The only FG you will find in any of my boats is the cowl and tail feathers if I built it. I have a FG 1974 Valu Mart hull that I've been restoring and the one pictured below that I've been racing for the past several years. I bought both, the Valu Mart being assembled by a guy in California that likes heavy boats(it weighs at least 8Kgs without fuel, radio gear, driver or any other detailing parts) while the one pictured below is 6.35Kgs RTR and is all FG with birch ply added to stiffen the bottom of the sponsons, used as engine bay side bulkheads to support the inner edge of the decks and used to build the integral radio box.
Attachment 2270401

Perfect.

It looks like I’ll have to remove this bulkhead completely. I was hoping to cut a hole in it like I’ve done but you won’t physically be able to get the batteries in with that bulkhead there at all.

I will need to support the deck strip though or it will lose it shape, so I’m thinking of cutting out a strip of aluminium the same shape as the inside of the deck strip and epoxying it in Joe (after trimming the bulkhead to fit it in. Then when I put the decks on and remove that bulkhead it should retain its shape in that area.

The worry then will be that the deck over the battery there will have nothing to rest on and might sag?
https://cimg1.ibsrv.net/gimg/www.rcu...a8b8f8e2e.jpeg

Had to think about this one for a bit. Since you're making the frames out of lite ply(not my first choice but what the heck), my recommendation would be to add a 1.5 to 3mm plywood doubler on one side of the frame in question from the top of the frame down to the top of the pocket you cut for the battery, taking it all the way across the hull. This will give you some additional strength and support for the decking, It may not need the added support but it won't hurt anything either

So, any updates?

Moving a little slowly :)

I decided, as I'm removing one bulkhead completely to fit batteries in, that I'd create an aluminum brace. I've done the braces that run down the boat but I will have a perpendicular piece mimicking the bulkhead (but with clearance underneath for the batteries) to support the deck on each outside edge, and strengthen the boat in this area.

https://cimg4.ibsrv.net/gimg/www.rcu...861a3aee05.jpg