New to boat building and introduction

[Ryanw]

A couple years ago we bought a cottage on a large lake. My now 8 year old son and I have been playing with some inexpensive 18" RC boats and having a great time. There are times when the lake gets a little choppy and we can't use those little boats. My Mother found a local fiberglass hull builder and got him (us) a 55" deep V hull for his birthday. It is in 3 pieces, the bottom, top and the hatch. It includes marine plywood stringers and a transom but they're not connected. It has a plain gray coating over the fiberglass on the outside. The hull looks in nice shape, but may need a few small repairs to smooth things out. The edges of the hull are bare fiberglass.

I've read some of the build threads here, but most of them start with a finished hull and primarily discuss components, so I have some basic questions.

I'm pretty sure I want to go electric for easy start, clean, etc, although my son wants a gas motor for noise and he wants to be able to start it. I've read about pros and cons of each but I'm open to more suggestions.

How do I join the two halves of the boat and when do I do it? I assume some fiberglass material, any tips for aligning them and holding in place?

When and how do I install the stringers and transom?

I figure painting is the last step, correct?

Any beginning discussion of components? I'm sure I'll have more detailed questions as we progress.

Thanks a ton!

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[Jesse J]

Hi Ryan, and welcome to the forum.

That is a nice looking hull and quite a deep plunge into the hobby!
If it were me, I’d ask the hull maker to join the hull.

Since you probably don’t have chargers, batteries or any of the components, be aware you will easily spend over $1000 on this boat before paint.
There is a rule in Fast Electrics: “speed, economy, reliability.... choose any two”

I’d recommend starting with a smaller build as a first. What are your building skills/experience?

Jesse

[Ryanw]

I did think about starting smaller, but odds are I'd only get "permission" to do this once. We really wanted something that could handle the waves at our lake so decided to go big. I'm pretty handy and looking forward to the challenge of the build. For us it's an opportunity to spend some quality time together building during the winter and enjoying during the summer. Right now I'm not looking for ubber speed since my son will be spending a lot of time driving. Unfortunately we've watched too many youtube videos of really fast electric boats and he thinks he wants to go 100mph.

[Jesse J]

I would encourage you to do searches on this forum, many build threads to scour.
For long run times.. I would consider gas for this boat. No chargers, batteries or esc trouble to worry about.
Big boats are expensive and as a first in your fleet, will require a lot of extra stuff.

If you go electric, don’t expect long run times. More than 4-5 minutes per battery charge is really challenging, especially if you want it to go fast.
Realize, those 100mph boats only go straight and for only a few seconds.

[Alfa Spirit]

55" is not a small hull...

You need a big motor like SSS 56104 / 730KV and 12S battery

[Ryanw]

Thank you, I've been looking at motors and wasn't quite sure where to start. What kind of run time can I expect using this motor and one or two batteries? Can I use lower voltage batteries for slower speed without significant changes to the boat configuration? I understand ESCs like to be run mostly full throttle.

The 100mph comment was very much tongue in cheek. I don't plan on setting any speed records.

[Alfa Spirit]

With a 55" hull you can run with 2 or 3 batteries in parallel.

[nhk750]

I keep hearing that ESC's like to be run at full throttle? I guess if your boat is set up for racing and propped for that then yes, but otherwise it all depends on how the boat is set up, what prop, motor, battery combination, amp draw, ect... It is true that there is less water cooling flow at slower speeds, but otherwise there is no issues with running at mixed throttle (not at full throttle) if the power system is setup for that. It is kind of a blanket statement that people make, probably mostly people that do run at full throttle for max speeds or racers. The ESC does not care what throttle setting you are at as long as your temps are staying within the recommended parameters for that particular ESC, the only thing that hurts the ESC is high temps, otherwise it doesnt care and that is what they were designed for in the first place, variable speed.

[Ryanw]

Since I posted last I've made a bit of theoretical progress, no actual work though. I had a good discussion with the hull builder about how to join the hull and install the transom and stringers. I'll do that once I get my internal parts and finalize the layout.
I've decided to go gas for run time, I hope I can still post here. Looking at a zenoah 30cc or clone.

I have a few more questions regarding parts.
Water pickup: what are the pros and cons regarding options? Right now I'm leaning away from rudder pickup simply because I don't like the look of the water tubes going into the boat. I will be using a clutch and water pump and I will need two inlets or split it. One to engine, the other to exhaust.

What are some general rules about sizing and placement of trim tabs and turn blades?

Rudder placement and size: I think I understand the offset to the right is to help with racing when there is more right turns than left. Would offsetting to the left make steering right and left more equal due to prop torque? What about center mount? What are the considerations for size and shape?

Thank you again!