Help needed - TFL Pursuit 32'' nitro build

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Luis Oliveira

Member
Joined
May 6, 2019
Messages
7
Hello everyone.

First of all, let me congratulate all of the intwaters community for being the best rc boating resource on the web.

I am relatively new to the rc boat picture. Been around cars, planes and helis for the last two decades.

Recently, I have gained an interest in boats. Last year I built a 26" wild thing, and a 17" outrigger hydro. Both of them made out of wood and with FE power.

I was looking into getting into nitro boats. As with all nitro models, the sound, smell and the engine tuning all play a big part into making this sport very interesting. Besides, FE boats that are bigger than mine quickly become very expensive in terms of batteries, motors and all the gear necessary to run them. (I mean multiple batteries and the means to charge them on-site).

My original idea was of building a 32" wild thing for nitro, but, building from scratch (although I love it) is a time-consuming task. Time which I don't have.

So, the plan here is to build a 32" fiberglass mono for .21 nitro power. I selected the TFL Pursuit hull as a base for this project. This hull is a clone of the delta force hull of the same size and is well spoken of all around.

I bought the bare fiberglass hull, already painted. I think it is pretty decent. Nice finish, pretty stiff, made out of fiberglass fabric and not matt (but probably made out of polyester resin, I really can't tell).

I now need your help to get it done. I need to know your opinion on a number of questions which are:

1- I obviously need to install some ply engine rails. I was thinking of 1/4" aircraft ply. Along with a transom doubler of the same thickness. The transom doubler seems easy enough. But how exactly should I go about the engine rails? Glue the rails with epoxy then reinforce the joint with fiberglass fabric end epoxy? Are there any tips/tricks I should know about this?

2- In every thread I find about this boat (all of them are for FE power), everybody adds a carbon fiber inlay in order to reinforce the hull. Is this really necessary? I mean, is not like this boat is going to haul 3lbs worth of batteries around. But, then again, the hull seems pretty thin. What is the "normal" thickness for a fiberglass hull this size (including gelcoat & paint) ?

3 - any other issues I should observe?

Thank you all in advance.
 
Last edited:

Jake Ellwood

Well-Known Member
Joined
Aug 11, 2019
Messages
56
Hey Luis, I cannot help you on your query as I have not built a mono but I wanted to say welcome and also give a wave. I live in Portugal near Lisbon most of the time. Also another member here is based in Portugal as well. We can meet up some time!

Cheers
Jake
 

brad nichols

Well-Known Member
Joined
May 10, 2010
Messages
2,434
Epoxy will bond to polyester but not the other way around. Roughen the hull where the rails are going to with 60 or 80 grit sand paper. 3/16 plywood is fine for a 21. Usually the centre of the flywheel is the CG point of the boat and a certain distance from transom ( can't remember ) use 4" spacing for motor mount and use a drop mount to keep CG low. Use a spacer block and bolt the rails to it and place in the hull and glue trails in and use some mat on the outside of the rails to secure them and to build a fillet. when dry scuff the fillet to take the fibres off ( having one stick in your finger and you'll know why ) the coat everything with epoxy. Jerry at Seaducer Boats would be the one to talk to as he has built a few!!

Brad
 

Luis Oliveira

Member
Joined
May 6, 2019
Messages
7
Epoxy will bond to polyester but not the other way around. Roughen the hull where the rails are going to with 60 or 80 grit sand paper. 3/16 plywood is fine for a 21. Usually the centre of the flywheel is the CG point of the boat and a certain distance from transom ( can't remember ) use 4" spacing for motor mount and use a drop mount to keep CG low. Use a spacer block and bolt the rails to it and place in the hull and glue trails in and use some mat on the outside of the rails to secure them and to build a fillet. when dry scuff the fillet to take the fibres off ( having one stick in your finger and you'll know why ) the coat everything with epoxy. Jerry at Seaducer Boats would be the one to talk to as he has built a few!!

Brad
Thanks. That is aligned with what I had in mind. But, I am kind of reluctant in reinforcing the rails with (just) FG mat. I have seen photos of hulls and I can see the FG fabric (roving) in there. Maybe FG mat, or epoxy mixed with FG chopped strands to build a fillet, and then FG fabric on top of it. What do you think?
 
Last edited:

Luis Oliveira

Member
Joined
May 6, 2019
Messages
7
Still I need some advice on reinforcement. I am totally new in this FG hull business. Should I go with it as it is, and just install the rails, and let it rip. Or, since I am at it, lay up a layer of Fiberglass or Carbon underneath the rails to stiffen it up?

I mean, just like I said before, on every build thread I see for this hull, I see people laying up a carbon fiber Inlay. I would like your opinion on it. If I was going to use FE power, I would do it like them, but, since the boat is nitro, and it isn't going to be much faster than 50-60mph, and it will not have heavy batteries onboard, i wonder if I really should bother doing it.

please chime in, people.

Some pics of a hull like mine with a carbon fiber inlay :
 

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brad nichols

Well-Known Member
Joined
May 10, 2010
Messages
2,434
If it is as thin as you say then go ahead and do a carbon overlay, now is the time to do it since it's new, install the rails over top. Fillet of cabosil and epoxy with either glass or carbon strip over that.
 

Luis Oliveira

Member
Joined
May 6, 2019
Messages
7
If it is as thin as you say then go ahead and do a carbon overlay, now is the time to do it since it's new, install the rails over top. Fillet of cabosil and epoxy with either glass or carbon strip over that.
It SEEMS thin to me (compared to a wood hull of that size, which is 3/32" thick). but, like I said, I'm new to fiberglass hulls and don't exactly know what the "normal" thickness is.

Does anyone out there who has a 32"-ish nitro fiberglass boat care to enlighten me?
 

FloridaScaleBoater

Well-Known Member
Joined
Oct 2, 2005
Messages
5,987
It SEEMS thin to me (compared to a wood hull of that size, which is 3/32" thick). but, like I said, I'm new to fiberglass hulls and don't exactly know what the "normal" thickness is.

Does anyone out there who has a 32"-ish nitro fiberglass boat care to enlighten me?
As stated earlier in post#6 make yourself some 3/16" wood engine rails, once you put them in place on edge, it will stiffen the hull bottom considerably.
while installing the rails, you will be glassing them in place with 2" F/G cloth tape Woven Fiberglass Tape
This in it's self will add even more stiffness.

Anything powered with a .21 engine you want to keep as light as you can. added weight is hard to overcome with an underpowered .21 engine.
 

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