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Sep 24, 2003, 08:32 PM
And just to keep this Aquarama oriented....

Dongledell;
Are you building from a kit or plans? Whichever, what is the name of the producer and how can I get a kit/set of plans?

Kapos;
The kit that you are showing pics of is the Italian one ? As I recall the hull is plastic and you apply mahagony over the plastic? I have seen only one of those built, but the quality looked to be very good, espescially the fittings kit.
The one I saw was powered by a stock 540 on a Hughey gearbox and ran rather well. Good speed considering the weight.

George
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Sep 24, 2003, 09:19 PM
George,
Not a kit that I know of only seen it complete at
various sites from $325 low to $500 high.

I was going to ask Dongledell the same thing..
Wheres the plans Havent mailed water skier
yet eh George?

So lets talk about finishes. Whats the difference in
weight and otherwise of a thick wood exterior
with spar urethane or acrylic paint vs a thin planked
on balsa with fiberglass and (8 ) coats of epoxy?
Rivas are all painted on bottom anyway.
Just speaking from my experience and I talked to Norbert
about this while back. Is most epoxy UV resistant?
I know west systems is but thats $$. Can you resurface
it easily when its scuffed? Your right Sterling kit wood
is not the best, I had so many fill spots on sides of
Seamaid Varnish look was pointless. I used acrylic paint
and 3 coats Spar varnish for stern. 13 years later and
looks good still. Spar varnish is $10 Quart. Epoxy?
Scratch spar varnish, sand and revarnish looks new.
Epoxy seems over rated and uneconomical to me.
Guessing its the only solution with fiberglass...

My 2 pesos

Brad
Sep 24, 2003, 11:50 PM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
Well in the original thread,
Dongledell was hunting for the plans. So I am
assuming he found some good stuff.
We had a look at that model, but only as a reference to just what a "Riva Aquamara" was. They are beautiful boats, and that diagonal side sheeting adds to something dynamic to a classic design.

I would ask for plans also, but I have enough to keep me busy for a while.

Fiberglassing: A lot of resin layers on a 52"(132cm) balsa hull, can bring the weight up to 4 pounds. If you apply the resin, and then literally squeegee the light fiberglass into the resin, and remove as much excess resin as possible the same hull could easily weigh less than a third that weight. The hull will still be just as strong as an over resin'd build up, and probably more flexible.

I have done a lot of fiberglassing, and I used to think the more resin the better. But when I am trying to shave grams of off some of my older ships, I can imagine where I went wrong.

As far as scratches a little wet sanding and and buffing with some protective marine wax can keep a fiberglass hull looking nice and protect it from UV damage.
(anyone besides me wax their boat hulls?)
Sep 25, 2003, 04:37 AM
and this wire goes where?
Thread OP
Hi Guys, sorry about the delay in getting back, no access to the PC last night (well, I was standing in a field in the middle of nowhere with my heli's!!! )

I'm building the aquarama from plans rather than a kit. they came from a company called Traplet ( you can find them under www.traplet.com , the plans are referenced MAR2552) If you get a set, I'd strongly recommend asking for the article that was published about it. Not because there are any usefull hints on construction, purely for the detail shots.

Overall I'm extremely unimpressed with the plans - I have searched for as many pics as I can on the original to get more info, as if you build purely from the plans it could either end up as an Aquarama or a viking longboat!!!! I dont know if this is just me being spoilt with accuracy on the heli and plane front, just hope boat plans are not usually this poor!! Instructions say such helpfull things as "you will need to be carefull when doing the planking" No? really!!

Kapos, I did see that model, but this was to be a "cheap" entry into boats for me, and more a project to re-introduce my wood working skills, which are becoming rusty since I went into heli's (not a great deal of wooden heli's around!) So far I've spent a grand total of 4 on it, and I'm up to planking stage. I've got all the timber by scouting the local dump and dismantling a Mahogany cupboard that my brother could not give away! fantastic quality wood too.

The pin stripes you mentioned are not fake on mine, they are inlays of lime wood between each plank.

George - many thanks for getting that info out. If your interested in the plans I'll send them on to you once I've got mine up and going. I would offer to send some out now, but no-where around here will photocopy them because of the copyright. Perhaps it could do a tour of everyone who wants one!!! be intersting to see the differences in the end result as well.
Sep 25, 2003, 07:39 AM

Riva Aquarama Kit


Kapos;
The kit that I am thinking of is by Amati (Italy). It is available thru www.modelexpoinc.com

They say list price is $629.00 on sale for $399.00(?)

My local hobby shop had one in stock for several years, and it was finally bought by a fellow club member and I think that he got it for about $325.00 including the running hardware package.
This kit is a resin hull that is then sheeted with mahagony.
As to the quality of the Amati kits, opinions vary widely, I have had people tell me the are the best, and others swear that they are junk, the detractors have typically said that they are difficult to build. I guess beauty is in the eye of the beholder. Personnally, I thought the quality was good, much better than Dumas.

Are you anywhere near Kay's Hobby in Portland? They carry a lot of the Amati line, and the few times that I have been in there I thought their prices were typically pretty good.

Finishes:
Lots of debate on that issue, and we could (should?) start a whole separate thread on that. West Systems is expensive, and I have personnally had an air bubble problem with it. Zillions of microscopic bubbles that only show up when you start to sand it.
I found a product called Evercoat, for half the price of West, and did not have the air bubble issue with it. My neighbor swears by the brand carried by our LHS. I did notice that it appears to be much clearer than either West or Evercoat, which have a slight coloration to them.
Personnal opinion again, I like to do 1-2 light coats of Epoxy with very light cloth and then put the final finish on as Polyurathane or automotive clear coat. With my building skills, I need the added strength of epoxy, or the boat would desintegrate on the water.
On the other hand, I have seen many fine finishes that have used no epoxy at all. That quarter scale Seamaid refered to, is an example (20 coats of varnish).
Epoxy does add weight compared to a varnish. The guys in my club that insist you need 8 coats of epoxy, do it because they believe that it provides a "depth" to the finish that you cannot get with varnish. They also are not concerned with the weight.
Sep 25, 2003, 12:00 PM
太刀風
Tachikaze's Avatar
Boy look what happens when you are away for a bit, things go off into many directions!
Lets look at several of the things mentioned:
Floatation - You don't need no stinking floatation! What do you imagine will happen that will make your boat sink? My combat destroyers have only sunk when shoot full of holes ( since I am an Axis skipper that does not happen very often) I have had the boat in rivers, lakes and streams. Have been run into by other destroyers, a canoe and have been attacked by a nutria. If floatation is a real concern for you, the best stuff to use will be R10 insulation foam. You can shape it to fit the open sections of your boat and can use it to hold things like batteries in place.
ESC - You DO NOT want to place two ESC in the boat to run two seperate motors. Unless you have two seperate controls on your transmitter to power each ESC individually setting them up on a Y connector will not work. All of my twin screw ships run on one speed control running two motors that are connected in series. I use R/C car speed controls on several of the boats. The Duratrak Blast utilizing 6.25Volts is on my 1/72nd scale Schnelleboote which is 21" long. The HIJMS Tachikaze (56 ") is running on 12V with a Tekin Rebel. The INS Alfredo Oriani (56") is running on 12V with a MCD older model micro boat ESC.
Motors - The boat the size you are building does not need a high amp 540 motor. Unless you want to stand the boat up out of the water you will not need that much torque. UMI RYUSUKI runs a 1/86 scale Fairy Boat with a Pittman 14V motor. This is a 14000 RPM low torque/low amp draw motor. On 12V this Fairy Boat will out run my larger scale Italian destroyer and even my torpedo boat. I do not think it is running to scale. You may need to check on that UMI I would look to use a smaller motor like we discussed, the 300 or 480 motors. I will check on E Bay or a place like All Electronics and see if there is something that I can find that would be like what I would suggest. If you know any one that works at a large hospital, have them check with the BioMed guys, the ones who repair the equipment at the hospital for spare parts. The 12V Pittmans are motors that come out of IV infusion pumps. They were FREE
Fiberglass - As echoed by George and Umi, you WANT to glass this boat. If you put all this work into making the boat pretty you need to protect that hull. Your hull needs to be complete, all the stripping and the inlays need to be in place before you glass it. Like Umi mentioned you need to squeegie the glass free of the resin to help reduce the weight. I will be glassing a fireboat and a destroyer on the weekend of the 5th of October. I will try to take some pictures of this project and have them posted so you can see the steps that are involved in glassing to make the boat strong but not heavy.
Sep 25, 2003, 01:16 PM
太刀風
Tachikaze's Avatar
Here on E-Bay are motors like what I and Umi have mentioned. Though this is an outrageous price for these motors. I obtain these and ones like this from the hospital for free. If you can find ones with a cannister like this in 14V I think that you will find that a pair will push the boat you are building at a very good clip.http://cgi.ebay.com/ws/eBayISAPI.dll...category=26209

<edit>

Ohh here is the motor that you want. If you can find these, this is what is used to run Umi's Fairy boat at warp 2.2
http://cgi.ebay.com/ws/eBayISAPI.dll...category=34058
Last edited by Tachikaze; Sep 25, 2003 at 01:19 PM.
Sep 25, 2003, 01:44 PM
Tachikazi;
I have several of both of those pittmans in my parts bin, plus some 32 volt units. Pittmans are the best. We have a surplus electronics store here in town, and I check them at least once a month for motors, and grab anything that looks good.
Typically I can get the Pittmans (when I find one) for under $3.00.
Dumas sells the Pittman for their paddle wheelers for $75.00(?) it has a built in 66:1 gearhead. I got 3 of them from the surplus store for $15.00! All of these are of course used, but with Pittman quality and the low abuse that I subject them to, they seem to last forever.
The surplus store also stocks new Mabuchi drill motors, 540, 550, 700, 750, & 800. I get these for $1.50 to $4.95 each. Much nicer than the LHS price of $30.00-$60.00. (Graupner)
Sep 26, 2003, 03:33 AM
and this wire goes where?
Thread OP
Tachikazi, thanks for those links - not sure what the availablility of those is like in the UK but I will go on the hunt later. we have an excellent surplus electronics store just down the road, so I think they will be a good place to start.

I understand what you and George are saying about the prices of motors - one of the electric heli manufacturers I've been looking at sells a motor to go with the heli at 45 ($76) whereas the discount place sells the same motor for 3 ($5) a PAIR!!!

Of course the problem is that if your new to the field, unless you've got help from people such as yourselves you just dont know what's good and whats not!

Back on track a tad, I'm now ready to start with the first planks. got the bench saw out today so I'll start stripping the wood down tonight. Any hints or tips on laying the planks up for a really good tight fit and finish?

On the glass front, I spoke to my father last night, who handily enough has 3 gallons of crystal clear epoxy and some GF tissue left over from his latest car project... that'll help keep the costs down! I'll definitely be interested to see some photo's on how you proceed with that - bit worried about ruining the boat with a botch job on the glass!
Sep 26, 2003, 04:06 AM
and this wire goes where?
Thread OP
More questions...!

While I was having a look at the plans this morning, I was trying to work out the best place to fit all the radio control gear and the batteries.

I know in a plane it is critical that you get the centre of gravity correct to ensure the thing will fly. Is it critical like this with boats?

Unfortunately the plans only show "possible mounting site for motors", and nothing else, so I really have nothing to go on at the moment! With regards to the restrictions of the hull etc, other than the first 8 inches of the bow there is available space just about anywhere!!
Sep 26, 2003, 07:27 AM
Dongeldell;
As to the application of epoxy, if your father has done car work, I would assume that he is familiar with the plastic/nylon spreaders that are sold (at least here) by the auto shops. They make a nice squeegee to get the excess resin off. A stiff piece of rubber will also work.
Couple of tricks that I have learned:
Don't stir the epoxy when mixing it, that introduces air bubbles. Pour the 2 parts into separate containers that will hold twice as much as just one part, then mix by pouring from container A to B, repeat until they are well mixed.
If working with the very fine cloth, give it a coat of hair spray before cutting it and applying it. The hair spray adds a little stiffness and also prevents the uncontrollable fraying.
Cut the cloth large than the area to be covered, it is easily trimmed later.
Keep an old pair of scissors handy, you will need to make small cuts and tucks in the cloth as you go particularily at corners and sharper curves.
Some say to apply a light coat of resin first then lay the cloth into the resin, others say to tack the cloth down first with CA, then apply the resin with a brush. I have used both methods and they seem to work equally well.
The critical issue is to make sure that the cloth is well saturated so that it will visually disappear, while not having excess resin that will cause the cloth to "float" in the resin. The squeegee process is essential.
Some runs/sags are inevitable, but they are workable.
Humidity and temperature will affect curing time, if you find that it is not setting up, try applying heat from a blow dryer.
Heat, while it speeds up the curing will also soften the resin enough to cause it to conform to curves etc. during the process. It works both for and against you.
Don't make up large batches of resin, resin sitting in a mixing cup will cure much faster than a thin layer on a hull. During the curing process it generates it own heat and will cause premature curing sitting in a mixing cup.
I generally mix enough to do the bottom first, let that sit until it begins to stiffen, then mix enough to do a side, etc.
I'm sure that others have different tricks etc that also work, and hopefully they will jump in here.
Sep 26, 2003, 07:45 AM
and this wire goes where?
Thread OP
George, my dad has quite a lot of experience with Fibre Glass, compared to mine which is no where near as extensive. he has indeed got some of those squeegies (not for long though!!)

Re the air bubbles in the resin - I have the perfect solution for removing those, basically a vacuum tank. I used to use it a while ago when I was a sculptor. if you are mixing up any 2 part casting materials (not exactly epoxy but works the same) once you have mixed them you put the pot in the vacuum tank and run at -1 bar for 2.5 minutes. It basically cold-boils it, expanding the air bubbles to 100 times normal size so they can push up through the mix and pop on the surface. after 2 minutes any bubbles remaining are less than a pin head in size, and completely dissapear when you release the vacuum.
Sep 26, 2003, 08:08 AM

Planking


Cut your planks to the desired width, so that all are uniform. Then it is a matter of fitting and trimming each piece as you go to insure the best fit.
Where do you start? I would play with several strips of planking on the hull to see how they are going to lay, and where you are going to have problems with curves. If planking horizontal, I try to start at a point where the first plank will lay perfectly parrallel to the chine/waterline, over the length of the hull, then go either side from there.
Dry fit each plank to insure a good fit, glue it down when you are happy with the fit. You will encounter areas where you will have to do a lot of trimming and fitting due to the curvature of the hull. Cheater planks are acceptable just make them look as good as you can and try to keep them in areas below the waterline. A cheater plank is basically one that is not of a uniform width over it's entire length. It usually ends up be tapered at both ends. You will know when it is time to use a cheater plank, as you will encounter areas where it is impossible to conform the plank to the hull with out severe twisting or gaps. At that point it is just a matter of figuring out the correct shape of the plank to fill the area. Always try to have the end of a plank be on a frame, not just hanging out in the air. Sometimes you absolutely can't avoid that, if so, do a good job of edge gluing.
Are you planning 2 layers of planking? I would recommend it. The first layer does not have to have as close of a tolerance, small gaps are acceptable. When the first layer is complete, you sand it to obtain the best possible shape, and can fill any low spots etc.
The second layer is then put on very precisely to get the ultimate fit with no gaps. I would think that it would be difficult to do the diaganal planking on the Riva without a base planking under it.
In fact looking at the shape of the Riva, I would think that it would be best to do a first layer of planking on the horizontal, and the second layer on the diagonal.
Also, you need to alternate sides as you go, complete 1 or 2 rows on the left side, then do the same on the right side. This prevents warping of the keel and frames. Do not do one whole side first then the other. You can stop the process at any point and leave it for the next day(s), provided the sides have an equal number of planks.
Sep 26, 2003, 08:39 AM

Centre Of Gravity


It is not as critical as in an airplane but, you need to be concerned with 2 dimensions.

The general rule of thumb for a Mono hull, is that the COG should be at a point 30% of the hull length, measured from the transom.

COG must also be centerd on the keel.

With boats the rule is keep the weight as low in the hull as possible.

With a mono hull trim tabs on the transom are some times needed to force the bow up or down, but only as a last resort.

The corners at the chines and transom should be as sharp as you can make them, not rounded. If a hull has strakes, those must also have sharp corners. The most common cause of porpoising in a mono hull is rounded corners at the transom.

And as strange as it may seem, the bottom should not be absolutely smooth for maximum speed. Most racers scuff the bottom with 400 grit sandpaper, diagonally from the keel to the chine.
Sep 26, 2003, 09:48 AM
and this wire goes where?
Thread OP
If I had known at the beginning of this project just how difficult it would be to research the aquarama I'm not sure I would have started!!!

when I received the plans I was not entirely convinced as to the accuracy of them. Having done my own research I know why! There appear to be as many different varients on the aqurama as there are days in the year. the plans I have appear to be a bit of a mix-match of several. I'm hoping to use a couple of pictures I have to do the work needed to make it like just one of them. Interestingly enough, most of the discrepencies appear around the stern of the boat, which is proving VERY difficult to get good shots of.

I have been lucky enough to be sent a 20 minute video on the aquarama which includes footage of the original construction. The planking on it appears to run horizontally, rather than diagonally as on the Amati model. I think I'll use the footage as reference and cross my fingers on the accuracy of the whole thing. One thing I have noticed is the windscreen on both my plans and the Amati model are no where near straked enough. More fiddling!!


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