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Feb 04, 2011, 11:15 AM
Registered User

Monsoon RC 900mm

hi guys,

i need help.

i just bought a monsoon rc boat. i am based in ireland.

i need to know the batteries pack code number and a recommendation of transmitter (2 ch) with battery pack code number that i can buy online. there are 2 wiring in the boat, 1 with white, red, black wiring and the other with orange, red, brown. both have j connector.

i am a beginner to rc boat and summer is just around the corner.
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Feb 04, 2011, 09:32 PM
Boomer1's Avatar
Before addressing your questions regarding the battery pak, radio and receiver, I suggest you take a little time to do a little reading to learn about your new boat. I had one, enjoyed it and once you do a few "repairs" or "upgrades" you will have a very nice boat that will give you years of fun.

Here are some notes from one of the threads on how to upgrade your Monsoon to make it sea worthy. You need to do these things before sailing it, or risk sinking your new boat. They are easy fixes and don't cost much at all.

The mast on these boats needs to be stabilized at the joint, or it will bend and possibly break.

On my Monsoon, the factory provided a cover for the “rudder well” which is nothing more than a thin piece of plastic coated paper. I replaced that cover with a plastic cap I had lying around my garage. If you use their cover and use silicone to secure it, you won’t be able to access they rudder connection without destroying that cover. As part of my regular maintenance, I remove the rudder to lubricate it with a water proof grease, so easy access is important.

I have read most of the forum threads on Monsoons that reported more issues with their boats than I experienced with mine. I have included some notes on the modifications I made to my Monsoon to prepare it for use.

1. Stabilizing the mast –

The mast comes in two pieces to facilitate shipping, but the method the factory provides to keep the two pieces together is inadequate, and will not hold it together in proper alignment. The Fix = drill four 1/16” holes in the mast using the two holes the factory has pre-drilled in the mast pieces as your starting points. Drill all the way though the mast and the plastic coupling that bridges the two pieces together. Be sure the pre-drilled holes in the internal mast coupling are lined up with the holes you are drilling and with the holes in the plastic bridge piece, (It has two holes already pre-drilled.) Be sure the two mast sections are perfectly aligned before drilling. I suggest you secure the mast pieces to a straight edge that you can lock the mast to, insuring the mast is in the proper alignment before drilling. Use SS bolts, flat washers and self locking nuts. This is really pretty simple, but care is required to insure you don’t mess up the mast and the internal coupling.

2. Sealing the electronics bay hatch for a water tight seal - This fix is for the Monsoon. The Phantom hatch is different -a bit better set up, but it can be improved upon.

The picture below shows the hatch modifications and the location of 4 servo arms which have been mounted to the deck. I used 4 small servo arms, trimmed to fit the space which now secure and seal the hatch. The 2 arms in the front, are rigid and don't move. The two in the back both swivel. I replaced the foam furnished by the manufacturer, replacing it high density foam (a good quality weather stripping will work fine.) The foam used on this boat was 3/8" wide, about 1/4' thick which allow the hatch to slide under the 2 front servo arms, which then compresses the foam and seals the front section of the hatch. The rear 2 servo arms are used as "lock down" arms that swivel out of the way to remove the hatch, and lock it down and seal it. I slide the front edge of the hatch under the 2 front "hold down" arms, and then I press down on the back edge of the hatch to compress the foam, and then swing the 2 rear servo arms in place. There is adequate pressure to create very water tight seal around the entire hatch. Simple and effective and doesn't look bad either.

3. Properly sealing the “rudder well”-
The cover provided from the factory for the “rudder well” is a thin piece of plastic coated cardboard. This issue here is that if you use their seal and use and adhesive to hold in place, you won’t be able to access the rudder connection unless you destroy the cover they provided. To address this I made a replacement from a plastic cap I had in my garage that I had saved for some unknown reason, and a cap plug from a hardware store. As the plug was just a little smaller the opening, I was trimmed piece of 2 sided foam tape to fit around the plug to making a good seal. It pushes in, and stays in. It can be removed to access the rudder well. Before inserting the rudder a lubricated the shaft with white lithium grease, and then I put a small O-ring on the shaft to help seal the tube the rudder shaft goes through.

4. Keel connections -
The keel is secured to the boat with a threaded shaft at the top, and bottom to attach the keel’s ballast pod. The factory shaft would be better if it were a bit larger in diameter to better support the weight of the keel assembly. Once you add 1.3 kg (1.3 kg = 2.8 lbs) of lead shot to the pod, there is a pretty good load on that shaft. As the boat goes though the water, the greater the load becomes. To date, I have no heard any reports of one breaking a shaft. I added a small O-ring to seal the shaft as it comes up through the hull.

My friend choose to epoxy the keel into the hull. This results in a strong water tight assembly. Granted, it makes transport and storage more difficult, but it fixes this issue. If you opt not to bond the keel, be sure you use properly fit O-rings on the shafts where the shaft meets the hull and on the top side as it protrudes upward. Use SS flat washers to prevent cutting into the fiberglass as you tighten the nuts. If possible use SS self locking nuts.

You may find that the keel shaft may need to be shortened or trimmed at the top to permit the factory provided trim plug to be installed (The plug hides the top of the keel mounting shaft) Mine was too long, and it had to be trimmed slightly for me to put the plug in the hole.

5. Securing the shroud guides-
My boat came with small plastic sleeves to prevent the spreader’s roughly cut holes from snagging the shroud lines, which sooner or later will be cut if the sleeves are not in place. The best way is to fix this is to de-burr the holes in the spreaders. An easier way is to put a little dab of silicone on each sleeve to secure it in place. My shrouds lasted a year, before they needed to be replaced.

The yellow balloons inside the boat are just a little added protection for my receiver and battery pack should an unforeseen event occur that results in getting a lot of water inside the hull. It is always a good ideal to put some kind of foam pieces in the hull to insure the boat will not sink.

I don’t know what type of radio you will be using but if you plan on using a 27GHz radio and receiver, I would suggest considering investing in a 2.4 GHz radio and receiver. They are far superior and provide a number of nice features that can add to your sailing fun. All it takes to power to the rudder servo and sail winch is a standard battery pack for 4 AA 1.5 volt batteries.
the 2.4ghz system, will address any potential issues with range and interference from other radio signals in the area that can affect 27mhz or 75mhz radios. You need a stick type radio, not a pistrol grip.

Did you get your boat from HobbyKing? They have a few very inexpensive 2.4 radios and receivers that should work fine for you. I included a picture for your reference. There are much better radios, but this is all you need to get started.

These links have the information above and some other helpful information for you: [

as well as this one:

This should get you stated - if you questions just post them and I am sure
your will get some good information.

Last edited by Boomer1; Feb 06, 2011 at 10:40 AM.
Feb 05, 2011, 03:24 AM
Useful Idiot
There is also a very good build thread highlighting a lot of the boat's issues on Mayhem
Aug 10, 2017, 07:35 AM
Registered User
Interesting notes Boomer, thanks for sharing. I like the hatch hold-downs!
RC boats are new to me and I'd like to share my notes on ballast/weight.
Weighting the keel:
Keen to get afloat I tried gravel (used for potting), nah too light! Steel panel pins, nope! only 640g after a lot of fiddling! This allowed the yacht to capsize in the lightest breeze! So I went with variable size lead shot from
(Priced per Kg includes P&P) BTW, the company is great to work with.
Due to the shape I couldn't fully fill, but managed 1.4kg
I made a paper funnel reinforced with sticky-tape. I then ladled the shot with a soup spoon over a sheet of paper (to collect spillage). Having split the tank (to remove the panel pins), I first sealed the edges with clear silicone, held together with the keel bolt (no spring washer!) and several elastic bands.
I'm now waiting on the weather to attempt my second sea trials. Waders ready!

I see 1.2 & 1.3 kg bounded around in the manual/website, one chap cast 2.8/3kg, and the 1metre class have a limit of 2.5kg. What weight do you use Boomer?

I have an existing DX6i Tx and have paired with an Orange Rx
For a battery I have used a 2s 6.6V 700mA LiFe cell. My original trials used a 3s 2.2Ah LiPo and BEC. This added to the stability problems, the LiFe is about 41g and so I've saved 185g as i no longer need a BEC either.
Last edited by Adub; Aug 10, 2017 at 07:43 AM.
Aug 10, 2017, 09:50 PM
Registered User
I would suggest a bulb weight of 1.6 to 1.8kg depending on sailing conditions. If you are still unhappy with the weight you have ie 1.4kg just get some lead sheet and temporarily wrap it around the base of the fin and go sailing to get the ballast weight you require. The smaller the diameter of the shot the more weight you can fit in ie less air space. Trapped air adds a small level of floatation. To get rid of the air once you are happy with the weight you can use epoxy or metal dust to fill the space between the shot. If the weight increase is only small you can glue the lead sheet on the side of the fin low down and shape to limit drag if you don't want to redo the bulb.

Not sure if it comes with a manual now that show correct orientation but the pictures on the HK web site show the fin on back to front (still does after 10+years). Should be as the photo.
Aug 10, 2017, 09:56 PM
Registered User
The servos are rated at 6V max. A 6.6 LiFe will be Ok but 700mA is not going to last long. Ok for a DF65 or similar but you need something around 2000+mA for some decent sailing time.
Aug 11, 2017, 11:48 AM
Registered User
I have been sailing mine for the last couple of months. I could never get the hatch to seal. it would always leak. So I just made a new cover out of balsa. Painted black and held in place with black electrical tape. No leaks.

I added small snap rings and snap swivels to make rigging it easier. I have a little car so I need to take the sail and mast off.

The cover for the rudder and keel bolt, I just used electrical tape. I also covered the small drain hole with electrical tape. I had the rubber plug fall out while on the water, brought it in with about a inch or so of water in the bottom.

I would suggest to not put the plastic parts on deck. I have had the lines get tangled up. I took them off and glued the holes closed.

I am using an old 4 cell nimh pack. I have had for 10 plus years.

I am in no way a sailor, yet I do really enjoy sitting there watching it cruise across the pond. This boat works well for me. I have been thinking of building one from scratch.

Aug 11, 2017, 12:28 PM
Registered User
I wonder what happened with the original poster? One post to his name in 2011.
Aug 11, 2017, 09:57 PM
Registered User
mfr02 - Unfortunately there are quite a few posts like this that ask for advice and you never here from again on forums. Would be nice to get a bit of feedback the info that was posted to help had helped their situation. A photo on the pond even better.

Buzz - I Cant agree more, I am a occasional sailor and on a warm sunny day nothing like following your yacht around the pond or even sitting in a deck chair as you suggest, a few refreshments at hand. This schooner is becoming a popular build around the world.
Aug 11, 2017, 10:14 PM
Boomer1's Avatar
Perhaps he was overwhelmed with all the information he was provided? Hope not! As usual the forum is there for folks looking for help. It is nice if those folks would provide us with a little feed back.
Oh well - we tried!
Aug 12, 2017, 12:12 PM
Registered User
Do we smell bad? Maybe we were just to dang helpful? We scared him off with information. Might have blinded him with Science?

I was toying with building the Americas 3 at 200%. If big is good, bigger is better. So I printed out the plans at 203% to get it with in 1/32 per inch scale. I go to the garage, start laying out the templates, I figure out how much material I will need. Houston we have a problem. Looking at it on the monitor, it look really cool. Best idea I have had in a long time. Well it would be 95 inches (8 feet) long and a mast 138 inches (11.5 feet) tall. Just think of trying to get that in a tiny Ford Fiesta. Not sure I could sail that at the San Diego boat pond?

I think I will stick to my Monsoon for now. Still, it would be awesome to build a boat like that.


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