General rules for Sport Boats?

[gooycheese]

Hi All,

I am working on building a Sport .12 boat this winter. I started cutting out my templates and have a few questions before I get to far into this.

1. Where is the balance point on a sport boat, is it the same as a rigger between the trailing edge and middle of turn fin?

2. The engine can be mounted to the bottom of the tunnel correct? Can I mount thru the bottom of the tunnel, the same way I would thru the sides of a tub on a rigger ( I use rubber hole grommets and nylon screws and delrin blocks) ( I will reinforce the tunnel where the engine goes ).

3. I noticed the the first bulkhead in the front sponsons doesn't connect across the tunnel, can I mod this so the nose block will attach to this bulkhead and both sponsons will be attached all the way across?

4. Now the plans I got call for alot of balsa to be used in this build aka all the bulkheads and stringers all 3/32. I plan on using a 5/64 stringers and the main bulkhead the turn fin is mounted to will also be 5/64 ( I will be doing the doubler for the turn fin mount ), everything else I was figuring 1/16 (transom will be 1/8).

5. Skinning the boat, I was planning on using 1/16 on the bottom of the tunnel and maybe 1/16 on the ride pads, otherwise 1/32 on everything else ( will this work )?

6. Lighting holes in the stringers, is this necessary? I was planing on foam filling everything on the side is that necessary? If not where is flotation added?

7. It was also suggested that I could add a carbon fiber tube across the front in say bulkhead 1 position does this sound correct?

8. This boat should weigh no more than really 3lbs correct, some of the sport 20's I see are under 4lbs .

I want the boat to be strong and durable not flimsy.

Thank You,

Paul

 

[opio]

is there a class for this boat? i have seen a whiplash scaled down for .12 and that has me wondering if i should follow in your footsteps lol? sorry i did not have any answers to your questions just added more questions

 

[gooycheese]

At the present time no there isn't a class, but I have heard rumors of some trying to get it going. In D4 Sport hydros have a really big turn out, some district from what I hear don't. The way I see it there was no A hydro's racing last year in our district except mine, this year there was about 4 and next I am expecting about 8. If the .12 sport boat follows the same path in a few yrs there may be a nice sport .12 class here in D4.

Paul

 

[LarryConrad]

Hi All,
I am working on building a Sport .12 boat this winter. I started cutting out my templates and have a few questions before I get to far into this.

1. Where is the balance point on a sport boat, is it the same as a rigger between the trailing edge and middle of turn fin?

2. The engine can be mounted to the bottom of the tunnel correct? Can I mount thru the bottom of the tunnel, the same way I would thru the sides of a tub on a rigger ( I use rubber hole grommets and nylon screws and delrin blocks) ( I will reinforce the tunnel where the engine goes ).

3. I noticed the the first bulkhead in the front sponsons doesn't connect across the tunnel, can I mod this so the nose block will attach to this bulkhead and both sponsons will be attached all the way across?

4. Now the plans I got call for alot of balsa to be used in this build aka all the bulkheads and stringers all 3/32. I plan on using a 5/64 stringers and the main bulkhead the turn fin is mounted to will also be 5/64 ( I will be doing the doubler for the turn fin mount ), everything else I was figuring 1/16 (transom will be 1/8).

5. Skinning the boat, I was planning on using 1/16 on the bottom of the tunnel and maybe 1/16 on the ride pads, otherwise 1/32 on everything else ( will this work )?

6. Lighting holes in the stringers, is this necessary? I was planing on foam filling everything on the side is that necessary? If not where is flotation added?

7. It was also suggested that I could add a carbon fiber tube across the front in say bulkhead 1 position does this sound correct?

8. This boat should weigh no more than really 3lbs correct, some of the sport 20's I see are under 4lbs .

I want the boat to be strong and durable not flimsy.

Thank You,

Paul

Jeez...not another class, are you trying to make Mendota a three day race? Your district has some of the best drivers,running some of the fastest Sport 20's in the country...scale that puppy up and run with the big dogs.

Just funnin" with ya' gooy...Running against the likes of Chris, Phil, David, and Bryon are reasons enough for me to make the trek to Dist. 4. That caliber of competition just ain't for everyone. A hydro class at TCMBC races usually have 6 to 8 boats running...bring your little stick boats up to Minneapolis.

Larry

 

[gooycheese]

Hi All,

So nobody has any of this info? I figure I will use fillets around the 1/16 ply for strength and I will also lightning as much as possible.

Larry. Mendota wont have these classes, if you wanna run a "A Hydro" it runs in the B class ( I will run my sport .12 in the sport .20 class as much as I can).

Thank You,

Paul

 

[Mark Leyde]

Hi All,
So nobody has any of this info? I figure I will use fillets around the 1/16 ply for strength and I will also lightning as much as possible.

Larry. Mendota wont have these classes, if you wanna run a "A Hydro" it runs in the B class ( I will run my sport .12 in the sport .20 class as much as I can).

Thank You,

Paul

Medota should put the A hydro (rigger) on. I would bring mine down. Terry Kelly how about you? Any others?

Not to bash the thought of the .12 sport hydro class. But There are way to many classes already. That only run half a field or less of boats at the races.

Mark

 

[opio]

1. i dunno

2. not sure, but i have be allowed to bolt my radio box straight through hull. (don't ask long bad day lol)

3. i dunno, but seeing as this is a "new" class/ fun idea, i don't think there would be a problem. that idea would help with strength.

4. that sounds good to me

5. i think it will work

6. lighting hole are a good idea, small boat save as much weight as possible, foam fill will be a good idea also, but make sure you don't blow them up with spray foam (another bad day)

7. Travis did that in his Vegas, seemed like a good idea cause he turned it into a sport 20. Not so sure you would need it here maybe just double up the forward bulkhead.

8. i would think the lighter the better.

now all this is coming from a guy (me) who is still working on his first wood boat. i do however know a bit about keeping water out of the people side of real ships so i hope this might help a little.

 

[LarryConrad]

Hi All,
So nobody has any of this info? I figure I will use fillets around the 1/16 ply for strength and I will also lightning as much as possible.

Larry. Mendota wont have these classes, if you wanna run a "A Hydro" it runs in the B class ( I will run my sport .12 in the sport .20 class as much as I can).

Thank You,

Paul

You should still plan a trip to the Twin Cities. I know of at least 4 new boats that will be running next season, which will make A Hydro one of the most popular classes run at our club. You could run your A sport boat too...though I don't think you would be as competitve as you would be running one of your riggers.

Larry

 

[LarryConrad]

Hi All,
I am working on building a Sport .12 boat this winter. I started cutting out my templates and have a few questions before I get to far into this.

1. Where is the balance point on a sport boat, is it the same as a rigger between the trailing edge and middle of turn fin?

2. The engine can be mounted to the bottom of the tunnel correct? Can I mount thru the bottom of the tunnel, the same way I would thru the sides of a tub on a rigger ( I use rubber hole grommets and nylon screws and delrin blocks) ( I will reinforce the tunnel where the engine goes ).

3. I noticed the the first bulkhead in the front sponsons doesn't connect across the tunnel, can I mod this so the nose block will attach to this bulkhead and both sponsons will be attached all the way across?

4. Now the plans I got call for alot of balsa to be used in this build aka all the bulkheads and stringers all 3/32. I plan on using a 5/64 stringers and the main bulkhead the turn fin is mounted to will also be 5/64 ( I will be doing the doubler for the turn fin mount ), everything else I was figuring 1/16 (transom will be 1/8).

5. Skinning the boat, I was planning on using 1/16 on the bottom of the tunnel and maybe 1/16 on the ride pads, otherwise 1/32 on everything else ( will this work )?

6. Lighting holes in the stringers, is this necessary? I was planing on foam filling everything on the side is that necessary? If not where is flotation added?

7. It was also suggested that I could add a carbon fiber tube across the front in say bulkhead 1 position does this sound correct?

8. This boat should weigh no more than really 3lbs correct, some of the sport 20's I see are under 4lbs .

I want the boat to be strong and durable not flimsy.

Thank You,

Paul

Paul

What boat are your plans for? is it a round nose or picklefork?

My PT SS Sport 20

balances close to the center of the turn fin

The motor mount is on aluminum angles bolted through the bottom of the hull with the rubber dampers on the sides, or where they would normally be if bolted through the side of the boat.

Don't know for sure about you other questions because I don't know what boat you are building. Rule of thumb...If it's not a Dumas boat build it the way it was designed.

Larry

 

[P THOMAS]

Gooey, This would be a fun boat. You are scratch building from your plan so how long and wide is this boat? You should make it the same size as the rigger and keep the weight down. What does your rigger weigh rtr no fuel?

 

[gooycheese]

Yes Phil the footprint is the same size at the A hydro I run, and I hope to have this boat 3lbs or less ( my A hydro is 2.2lbs rtr). The boat I am building has everything designed around balsa bulkheads and stringers, I dont want to use balsa. So basically I am building this with templates and my own wood choices.

Thank You Guys

Paul

 

[russ72]

Yes Phil the footprint is the same size at the A hydro I run, and I hope to have this boat 3lbs or less ( my A hydro is 2.2lbs rtr). The boat I am building has everything designed around balsa bulkheads and stringers, I dont want to use balsa. So basically I am building this with templates and my own wood choices.
Thank You Guys

Paul

sorry a lil off topic, but can someone tell me what class i would run a 36" aeromarine sprint cat?

 

[piper_chuck]

sorry a lil off topic, but can someone tell me what class i would run a 36" aeromarine sprint cat?

Yup, it is off topic. I'll post a quick reply. If you have more questions, I'd encourage you to open a new thread. A cat is not a 3 point hydro, so it's not legal in the sport hydro classes. However, it is a hydro, so it is legal in other hydro classes. So, you could run it in the appropriate hydro class based on the engine you have in it. For example, my 36" Sprintcat has an OS .81 VR-M, so if I have run it in IMPBA F Hydro. In addition to this class, if it meets the graphics requirements of offshore (number, sponsor, driver or simulated windshield, you could race it there. And another option is if your district offers an open cat class. So, the answer really depends on what you have installed to make it go.

 

[russ72]

sorry a lil off topic, but can someone tell me what class i would run a 36" aeromarine sprint cat?

Yup, it is off topic. I'll post a quick reply. If you have more questions, I'd encourage you to open a new thread. A cat is not a 3 point hydro, so it's not legal in the sport hydro classes. However, it is a hydro, so it is legal in other hydro classes. So, you could run it in the appropriate hydro class based on the engine you have in it. For example, my 36" Sprintcat has an OS .81 VR-M, so if I have run it in IMPBA F Hydro. In addition to this class, if it meets the graphics requirements of offshore (number, sponsor, driver or simulated windshield, you could race it there. And another option is if your district offers an open cat class. So, the answer really depends on what you have installed to make it go.

thanks for the info .

 

[TOM MOORE]

Hi All,
I am working on building a Sport .12 boat this winter. I started cutting out my templates and have a few questions before I get to far into this.

1. Where is the balance point on a sport boat, is it the same as a rigger between the trailing edge and middle of turn fin?

2. The engine can be mounted to the bottom of the tunnel correct? Can I mount thru the bottom of the tunnel, the same way I would thru the sides of a tub on a rigger ( I use rubber hole grommets and nylon screws and delrin blocks) ( I will reinforce the tunnel where the engine goes ).

3. I noticed the the first bulkhead in the front sponsons doesn't connect across the tunnel, can I mod this so the nose block will attach to this bulkhead and both sponsons will be attached all the way across?

4. Now the plans I got call for alot of balsa to be used in this build aka all the bulkheads and stringers all 3/32. I plan on using a 5/64 stringers and the main bulkhead the turn fin is mounted to will also be 5/64 ( I will be doing the doubler for the turn fin mount ), everything else I was figuring 1/16 (transom will be 1/8).

5. Skinning the boat, I was planning on using 1/16 on the bottom of the tunnel and maybe 1/16 on the ride pads, otherwise 1/32 on everything else ( will this work )?

6. Lighting holes in the stringers, is this necessary? I was planing on foam filling everything on the side is that necessary? If not where is flotation added?

7. It was also suggested that I could add a carbon fiber tube across the front in say bulkhead 1 position does this sound correct?

8. This boat should weigh no more than really 3lbs correct, some of the sport 20's I see are under 4lbs .

I want the boat to be strong and durable not flimsy.

Thank You,

Paul

Jeez...not another class, are you trying to make Mendota a three day race? Your district has some of the best drivers,running some of the fastest Sport 20's in the country...scale that puppy up and run with the big dogs.

Just funnin" with ya' gooy...Running against the likes of Chris, Phil, David, and Bryon are reasons enough for me to make the trek to Dist. 4. That caliber of competition just ain't for everyone. A hydro class at TCMBC races usually have 6 to 8 boats running...bring your little stick boats up to Minneapolis.

Larry

The amount of classes really IMO does not matter because as a club you can offer the classes you want to. Nova has a great little .12 out that is blazzin fast. I hope that district 5 gets a A class of some kind offered in district 5 we need nitro classes period. they sip fuel and in a .12 hydro set up right will run like the wind. Wish i could help you Paul, with a new hull design it trial and error. Good luck with your project.

Tom

 

[dschigoda]

Yes Phil the footprint is the same size at the A hydro I run, and I hope to have this boat 3lbs or less ( my A hydro is 2.2lbs rtr). The boat I am building has everything designed around balsa bulkheads and stringers, I dont want to use balsa. So basically I am building this with templates and my own wood choices.
Thank You Guys

Paul

Paul,

Very interesting! Does it look like it would be possible to hide the tuned pipe under the deck or cowl on this boat?

Which A hydro are you using to supply the "footprint" dimentions?

Thanks.

Dave

 

[gooycheese]

Yes Dave I am going to do everything I can to hide everything under the cowl. I am starting with a 1/13 scale 1980-81 pay&pak FE design. I am making making changes to this design but what is touching the water should be really close. The cowl will be my own design ya know a combination of stuff Ive seen. The overall boat will be about 13"x26" which is really close to my .12 rigger.

Thanks Tom I hope this boat works with the changes I am making. I am trying to incorporate alot of what i see in a David Preusse sport 20 , built in radio box in the nose of the tunnel and his cowl which mine will be a little more simplified.

Thanks Guys

Paul

 

[Ron Olson]

Paul, as you know, I'm working on a Sport 12 boat also but right now it's at a snail's pace. The strut and rudder are bolted on but that's as far as it's gotten so far. Other parts are sitting here but have to wait for other things to show up first before they can go in.

In trying to get help for mine, I went to the FE guys but they were zero help so far so I'm getting the feeling that I'm kind of alone again on getting mine floating. This is nothing new to me as I build a .12 mono about 10 years ago that I spent a lot more time searching for parts then putting them on. Things are a lot easier now, believe me.

Once the shoehorning gets in gear it looks like it will be more like an electric boat as there really isn't room for a radio box in it.

I'm going to try to keep the pipe under the hatch also but that alone might be a challenge. Right now if you didn't know I'm using a Delta Force Vortex hull.

 

[Glenn Quarles]

Paul, as you know, I'm working on a Sport 12 boat also but right now it's at a snail's pace. The strut and rudder are bolted on but that's as far as it's gotten so far. Other parts are sitting here but have to wait for other things to show up first before they can go in.In trying to get help for mine, I went to the FE guys but they were zero help so far so I'm getting the feeling that I'm kind of alone again on getting mine floating. This is nothing new to me as I build a .12 mono about 10 years ago that I spent a lot more time searching for parts then putting them on. Things are a lot easier now, believe me.

Once the shoehorning gets in gear it looks like it will be more like an electric boat as there really isn't room for a radio box in it.

I'm going to try to keep the pipe under the hatch also but that alone might be a challenge. Right now if you didn't know I'm using a Delta Force Vortex hull.

Ron, how big is the Delta Force? I didn't have much trouble at all getting the stuff in my Dark Horse and I thought they were about the same size.

Let me know if I can help at all.

Glenn

 

[Ron Olson]

Glenn, here's a link to show you what it looks like: http://www.deltaforce-hk.com/vortex.html . I'm hoping that a NR .12 will fit in there (it should) and the plan is to use one of your pipes also. That stuf is going to have ot wait for now as my main idiot box went south last week and gotta have some money for that holiday next month.

I bought a yellow one from Steve at Offshore Electrics..

After mounting the rudder on the right I'm wondering if I should have put it on the left side. I'm at the stage right now where I could do that if I need to. I've got a Grimracer turn fin but it looks kind of big. That could be trimmed down also if neccessary.