FE30 build help

[gwweber]

I am rebuilding a used insane fe30 hydro. When i checked my Center of gravity it takes several ounces of weight on the tips of the sponsons to make it balance I fly RC Airplanes and know how critical this is, should i throw some lead in the tips of the sponsons and use spary in foam to hole it in there? Guess the best thing would be to use stick on weights first. Guess if I was to get very serious with this boat i would move the motor up instead of adding weight. Right now it is in there very well and moving it would be a huge painstaking task as i but two graphite thin wall spars in the boat and used very good epoxy

[electric]

I would run it first. What is your COG point currently? I own this particular boat and I am not sure how you could get the COG that far off as the shape of the hull kinda forces you to move the motor forward to a degree. You should be able to get your batteries up far enough to get the COG where you need it. I run the boat in two configurations. Either 2s1p with each battery pushed out and forward as far a possible, or 4s1p where the battery can be pushed forward as far up into the nose if needed. Is your COG anywhere in the vicinity of the turn fin?? You can also do some adjusting with the strut angle if needed.

If the COG is too far back the worst that will happen is probably a tendency to blow over at high speed. Might consider more battery weight than lead as much as possible. Let me find the link to my most recent FE30 as a comparison point for you.

[electric]

Does your build resemble this?
http://forums.offshoreelectrics.com/...ace&highlight=

[gwweber]

motor placement same moved servo up just behind motor and havee esc in the nose. A tad tail heavy with the batteries still.

[Chilli]

Believe me Gary, CG is much more critical on an airplane then a boat but it is still very important. Not only will the nose come up if the boat gets loose, the boat will not turn well if the CG is too far behind the turn fin. Also the having the weight too far back can cause the transom to drag in the water slowing you down while increasing amp draw. Keep in mind a recommended CG is just a guideline to get you close. Pond time will determine the ultimate set up of the boat. So where is the cg in relation to the turn fin?

Don't use spray foam in your boat. It has been known to bust hulls open at the seam. Two part foam sold by Kintec and US Composites is what you need to use. I used it in my FE30's sponsons just for additional floatation. For now, just build the boat without any additional weight and let's get it in the water and see where we're at.

[MarkF]

My cg is 1" behind the sponsons.

Mark

[siberianhusky]

After rebuilding two used hulls that were foamed I would NEVER EVER put any kind of foam in a hull!
Spent hours using a screwdriver trying to pick that crap out of the nose of a mono to fix a very minor seam problem.
To be honest if I buy another used hull I'll be asking about foam and passing on the deal if there was any in the hull.

[Chilli]

After rebuilding two used hulls that were foamed I would NEVER EVER put any kind of foam in a hull!
Spent hours using a screwdriver trying to pick that crap out of the nose of a mono to fix a very minor seam problem.
To be honest if I buy another used hull I'll be asking about foam and passing on the deal if there was any in the hull.

To each his own. I've used two part foam sparingly in most of my boats. Never had a problem.

[siberianhusky]

LOL wait until you have to repair one and I can guarantee you will be cursing it. I thought the stuff was a great idea although I had never personally done it to a boat. One repair was all it took for me to do a 180 on that.
I fully admit I have no idea what kind of foam was used but I think it absorbed water over time as well. That boat lost a ton of weight after the foam came out. Had to move the batteries forwards a surprising amount to get the CG right again. No way the amount of foam in there could have weighed that much to start with. By the volume it should have been a couple oz. max.

[rickwess]

LOL wait until you have to repair one and I can guarantee you will be cursing it. I thought the stuff was a great idea although I had never personally done it to a boat. One repair was all it took for me to do a 180 on that.
I fully admit I have no idea what kind of foam was used but I think it absorbed water over time as well. That boat lost a ton of weight after the foam came out. Had to move the batteries forwards a surprising amount to get the CG right again. No way the amount of foam in there could have weighed that much to start with. By the volume it should have been a couple oz. max.

It must have been spray foam. Two-part foam easily shapes with sanding. Assuming you have access, I couldn't see it taking more than a few minutes to get the majority of foam out of a cavity.

[gwweber]

LOL I was worried about that.

[siberianhusky]

No way I could get my hand up under the deck of that 29" mono, had to use a screwdriver to break it up into little chunks and pull it out that way.
It's stuffed full of pool noodles now, My whiplash 20 is basically a wood over foam build, used pink insulating foam.

[ray schrauwen]

Sorry about that Mark. it was the flavor of the day back then to use expanding foam. It came from a can, Great Stuff huh?

After rebuilding two used hulls that were foamed I would NEVER EVER put any kind of foam in a hull!
Spent hours using a screwdriver trying to pick that crap out of the nose of a mono to fix a very minor seam problem.
To be honest if I buy another used hull I'll be asking about foam and passing on the deal if there was any in the hull.

[Brushless55]

motor placement same moved servo up just behind motor and havee esc in the nose. A tad tail heavy with the batteries still.

What do you mean by tail heavy ?
could be a strut adjustment as well