Hi all!

Lets see… a long time ago, in a pond far, far away… a friend sent me a new prototype hull to be tested. There even was a discussion on the RG65 yahoo group about the posibility of a monotype subclass inside the RG65 class depending on critical mass but in the end i believe that it didnt went much further than that… In time several of us received this hull with the idea of build it ant test/match race it against other RG’s and see how it ended up but after almost two years, as far as i know none of the recipients of the files ever built the thing… Well, after all i finally managed to get the time to start it… The boat is a design from ClaudioD based on one of his AC hulls but slightly modified to suit the specs of a more common RG-65… as you may think, a “scaled to RG” AC hull displaces somewhere near 650/700 grams which is too light for the common boats so the hull was made a little fatter amidships to get the extra volume to reach 950 grams aproximately…

As noted above, the boat has been started and it will be finished in a balas/glass mixture (balsa for the hull, glass for the deck), hull has been planked, coated and sanded a few times and it is almost ready to be taken out of the construction jig to be coated inside a few times. Rudder and keel will be helicopter blades (both carbon) for ease of construction and depending on how the hull ends up behaving it might be one of the changes to be done after testing. Target weight for hull/deck/keelbox/tray is 150/160grams and the electronics will be one gws 2bbmg servo for the sails and one gws naro/pico for the rudder all under a 4AAA pack (if i manage to find one at the lhs btw, if not, 4aa standard rx pack). Rig will be an A-rig bermuda classic and depending on how the boat ends up, a swing rig might be on sight…

A few pictures of the hull construction and before being moved from the cradle, rudder, mast:



Hi German - I guess I better admit I was one of those who asked Claudio if he would draw up some lines - and I was the one who sent out sample drawings to a few selected sailor/builders, and I was the one who dropped the ball and never built my own. I guess I am in big trouble - so perhaps I better finish up my personal RG65 and then get going on “my” version of Claudio’s AC design.

On a positive note, I retire on April 30 this year, so perhaps I will have some “free” time to finish the builds. Unfortunately my wife knows of my retirement - so maybe not so much free time after all. :help:

Thanks for posting the photos. Looking forward to the others as you continue your build.

Best regards, Dick

Hi, German,
850 to 900g displacement is feasable for a RG65 without too much effort. This will end up at approximately 900-950g, because appendices have a volume, too. Keel fin and bulb have about 50g … (round about 1/10 of the weight, because lead has a specific weight of 11g/cm³). However, a weight of about 1 kg is better for a general purpose boat, so you are on the right track.

Anyway, it is a nice project. Keep us informed.

Concerning the r/c equipment. If sticking with NiMH, Sanyo Eneloops are a good choice. They work well in a RG and AAA-type packs are available. However, in strong winds and when it’s cold, the small Eneloops come to their limit and it is better to use an AA type pack instead.
Why not going to LiFePOs? The LiFePOs can be used for much higher currents. I have just successfulls tested a setup with a Multiplex M-Link radio, a Hyperion DH13-FMB for the sails and a Dymond D 60 S HT fur rudder.

Voltage is 6.6V instead of 5V but both servos can be powered even by LiPos (7.4V), but LiFePOs are more robust. 2s LiFePOs are now available with 600mAh (Topfuel) and 850 mAh (Hyperion). Weight is similar to that of a 4xAAA NiMH pack.

There are more and more ‘high voltage’ servos on the market and most of the servos applicable as sail servos can be powered by LiFePOs (but not by LiPos!). The small rudder servos are still aproblem. There the D 60 is the only one if found so far.
Up to date receivers have no problem with the higher voltage and can be driven with up to 8V or even more.

@Dick- you are a lucky one. I have still 8 years to go with less and less time for sailing :frowning:

Hi guys!
Thank you very much for your interest and words on this little project!!!

Dick: Yes you are in deep s…t now!!! :slight_smile: with all the spare time you will have starting in april you better start finishing & building dude!!! and tell the wifey that you need a month or so of “workshop retreat”.

Joachim: My boats are always on the heavy side (1100+) so less than 950 is new to me and my poor balsa skills. Following the drawings from Claudio/Dick, the total displacement is 950 with 550 on the bulb which up to this moment seem feasible by my standards… im finishing the hull and the thing so far is is 51 grams (shell only) but my fear is that is too fragile so probably im glassing it on the inside as the outside is almost smooth ready for paint.
About electronics and sticking to nimh’s, the aaa pack i can get locally is a hobbico 4aaa pack 1800mha which for me is great. The one that im using all the time is a 4aa hitech which came with my laser radio. I’ve read about LiFePOs but as im in a budget here they are out of the question at least for now. Probably on the near future and depending on how the boat turns out it will be more than considered together with better servos. One thing to consider also is that here is kinda difficult to get all the brands you guys have in the states or europe. Here, as the reality for the hobbyshops is not as big as the scope is outside latin america, the stores poretty much stick to Futaba, Hitec, Spektrum and a lot of cheap chinese brands (hence the gws or art-tech stuff) and in a small quantity they get some other stuff such as the hyperions. The store has them in stock (the 850mah) but the price for it and the charger is way too much at least for this test boat. We will see after the first tests if getting better stuff worth the costs… receivers-wise, the only two the stores have in stock now are the 3ch hitec one (too heavy) and the standard 2ch futaba (i use am radios so crystals are my stuff)…
Well, as noted above, the shell is weighting 51 grams and is way too fragile in some areas i think. It will be glassed on the inside at least from amidships aft. The outside is already varnished/putty-ed/sanded and pretty much ready for the paint job (done by my trusty iwata from my other hobby) which will be a very well know one (AC speaking)… Also yesterday we went nuts melting lead here at home with a friend as we were molding the bulbs for his and my boats, in the end we did 4 bulbs and mine will be finished after the boat/rig. My goal is to have more than the 550g the drawings state (600g sounds reachable and maybe even a bit more than that).

Thats it for now!!


Hi German,
nice to see your decision to build the AC65.
I just want to tell that in case you like to use a classic rig, then is better to reduce the lead. It depend on the surface ratio Main/Jib, that a lead may vary from 7.5 to 8.5%, see Revision 1.
The rudder is also modified and recessed to avoid part of the fin turbulences. To increase the efficiency, the aspect ratio is also changed including the elliptical form.


AAA with 1800mAh - never. Either it is a typo or it’s an AA pack.

If you get a AAA type NiMH with significant more than 850mAh (and an AA with more than 1800mAh) forget about it. The so called “high capacity” cells have a very high interior resistance which will cause a breakdown of the voltage under load. “Good” AAA NiMHs have an Ri of less than 50 mOhm. The ends up in 200mOhm per pack wich causes a voltage drop of 0.2V when loaded with 1A.
In strong winds you can have currents up to 3A, which will result in a voltage loss of about 0.6 V (mark: with good cells!). The cable resistance and the contact resistance of the plugs will easily get in the same order of magnitude - lets assume another 0.4 Volts. Than you have a voltage drop of 1 V, which means the typically 5V of the pack go down to 4V in a gust. This is the lower limit necessary to close haul the sails with acceptable speed. Higher Ri means less voltage which slows down the servo further and may cause the receiver to reboot in the worst …

In the best case, you will get much less out of the cells than expected.

I have started the same way, happy to get 1000mAh NiMHs, some years ago. Panasonic and GP were somehow satisfying, but the cells went down after two years. I have them all kicked out in the mean time and have used only Eneloops for the last 4 years. They are as fit as in the first day.

However, telemetry told me last year, that in a similar set up as you are using only when hauling the sheets at light winds, the voltage broke down to about 4.2 V. In a gust I measured the above mentioned 4V. An accu pack from another vendor with a already reduced capacity broke down to below 3.8 V …

Don not underestimate the load to the sail servo!

Btw, a Hyperion LiFePO is not much more the an Eneloop pack here in Germany. 4 AAA Enenloops cost about 12€, the Hyperion LiFePO about 16€

Joachim, thanks again and yes, it was my bad… AAA with 750mah ( is the correct info. Not sure which cells it uses but here is a common sight on the RG’s. I havent seen the eneloops here but the cadnicas and some GP’s are available. The hyprions at one of the stores here is almost u$50, not sure if the other store has them…

Claudio, Thanks for your post and the modified version…please let me know if you feel confortable moving the CE aft of the CLR by the same 8% lead aproximately… im considering both options for the rig, one fore and one aft of the CLR…



High discharge / low capacity - should be ok for a standard NiMH and suitable for a RG. Will have a high self discharge. Don’t expect a long lifetime.

Happy Easter!

Hi German,
the CE is never after the CLR and generally is on the vertical line passing trough the front edge of the Fin (see read line) - 7.5% of LWL starting from CLR.
Nevertheless, because the of the Beam/LWL ratio of 0.20 it may be necessary to reduce the potential* weather helm, and it is not escluded that the mast step could be moved a little toward the bow = 8…0% or more.
Instead with the use of a Swing Rig , the lead could be further increased, after trials, to 9.0-9.5% .

  • A wide hull has natural tendency to go to the wind much earlier then a narrow hull.

Thanks for the replies Haegar and Claudio…

As an update, i thought the hull was ready for paint on saturday so i grey-primed it and to my bad it will have to be stripped all over as the surface looks awfull so more putty and sanding on sight (which sucks big time btw!)


Is it possible that the RG65 I purchased is a modified AC-65A ? Here are a few pics
Thank you

I dont think so since the stern, is rather large compared to my design and deck / cockpit are differents. See attachment.

Bob - even though Claudio posted the line drawings - I don’t believe I sent out more than 4 or 5 copies - and not many here in the US at the time. Not to say anyone built to them, but haven’t seen any photos of design on the water.

Also, as they say - seems I am busier in retirement than when I was working. Grandchildren do that to you, however. Have to enjoy them while they are small.


Thank you Claudio and Dick for the response.
I believe I may have found my boat in a picture. It was sailed by George Reed, Sail# 830. The boat is listed in the results as a " Modified AC-65A" The deck is different than Claudio’s design , as is the transom, it is angled. But the other dimensions are the same.
If anyone has contact info for George, I would like to contact him
Thank you

Bob - too many things with your boat that don’t compute …

  1. RG65 sail numbers (today) are at 300 series - not 800.
  2. Claudio’s drawings were issued about September 2010 - so it may have been early 2011 before the boat hit the water.
  3. The shape of the bow is not the same as the ACC boats of the time.
  4. I have no idea why the builder would have built with the rudder raked so much. Most rudders have the leading edge vertical. You should make a point to fix this during restoration.
  5. May want to verify the date and location of the event in which the “results” were listed. Perhaps a club member might have more info if it was a local regatta.
  6. If no response regarding George’s whereabouts, try the AMYA Membership Secretary. She (Michelle) may be able to cross reference the name and/or sail number. <>

If it really was based on Claudio’s drawings as a “Modified AC-65A” it looks like it had a pretty tough life in those 3+ years it may have sailed. Again, the one trademark of an ACC boat was the side view of the bow - so why it was modified as it was is beyond me.

Good luck on the restore and tracking down more info.

Dick L.

Hello Dick
Thanks for your insight. Here is the pic from the link and the link with results. It is the boat in the middle.The only difference I see from the boat in the pic, is the raised full bow and color of course.The rest of the deck looks the same. Maybe the full/raised bow is to limit nosediving ? I don’t know, I’m not a boat designer. I agree, the rudder seems to be raked more than other boats I have seen, but I think I’ll try it as is to begin with.
All the best

Hi Bob - here is info you requested. George Reed is a member of the Titusville Model Sailing Club and the following is his contact information - taken from the AMYA Club Listings. The club is Number 95

|Titusville Model Sailing Club|
| | |Contact: George Reed|
| | | Email: George Reed|Classes Sailed: Soling 1M|
| | |4805 Cocoanut Drive|Area served: Titusville,Florida|
| | |Titusville, FL 32780-6908|sail location: Chain of Lakes Park |
| | |321 543-9990|
|I would be surprised if you don’t see a lot of weather helm with the slanted rudder, but it is something to discuss with George. He served as Vice Commodore in 2012 and then as Secretary/Treasurer in 2014. Good luck in your efforts to make contact.


PS Glad I could help in tracking his down.

Thank you Dick
Tried the Email listed, it came back as not valid. Called the Ph # listed and got a voice mail.
I will try and contact other members of that club.

Hi All, I just finishеd my Ac-65. It’s my first rc boat so I decided to build it in wood. It’s become little heavier but next will build in glass epoxy.

Senior Claudio, Thank You for your beautifull drawings.


Hi All, I just finished my Ac-65. I build it from wood, no glass coat. It’s little heavier ( that’s my first rc boat) so I decided to put lighter bulb to stay under 1kg. Next will be glass epoxy.
Senior Claudio, Thank You for you beautiful drawings!

First test