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Author Topic: What to Buy ?  (Read 5114 times)

Martin13

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What to Buy ?
« on: November 08, 2007, 11:04:48 am »

Hi to all.
I have been bitten by the sub bug. Ive seen a few and now want one. I have been scratch building a Patrol boat for some time now and it still will not hit the water for at least another year, but am currently confused by some sub terminology. Can someone please explain to me what is a "stuffing box" and the term RCABS???
I have had a number of questions re purchasing the Robbe U-47 (I like its looks) and converting to static dive but all my questions have been answered on previous threads.
I have how come to the conclusion of leaving it as is and just use it as a surface model then sometime in the near future (if the wife doesn't catch on)  purchase an Engel Sub.

All thoughts and opinions appreciated

Martin
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DavieTait

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Re: What to Buy ?
« Reply #1 on: November 08, 2007, 11:20:41 am »

Martin the best thing to do is build the Robbe U-47 as its delivered  ( a dynamic diving sub ) to get used to diving a sub and working with the tech-rack. After building it is more than possible to install a piston tank and convert this sub into a static diver.
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dreadnought72

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Re: What to Buy ?
« Reply #2 on: November 08, 2007, 03:16:46 pm »

Stuffing Box - a (hopefully) watertight seal around a propshaft.
RCABS - Recirculating Compressed Air Ballast System. Uses an air pump and the gas contained within the sub to fill/deflate a bladder in order to change bouyancy. Doesn't vent gas and so offers more cycles.
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Martin13

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Re: What to Buy ?
« Reply #3 on: November 09, 2007, 06:49:30 am »

Many Thanks to Davie Tait and Dreadnought72.

Yes Davie, that would be the wise thing to do. I have also taken a liking to the Engel VII/C and have been offered a way to get it directly from Engel and delivered to me freight free in about 6 months time. ( I have a German neighbour thats a merchant seaman. he dissappears for six months at a time - I wonder what else I can buy in Germany!). Now with the similarity to the Robbe U-47 would it be better to buy the Robbe XXI now instead of the U-47 or is more expertise required?. According to the write up on the Robbe website, both subs internals are very similar.
The stuffing box - is this at the WTC end or prop end?
One more item - with regards to a dynamic diver, should the sub hit reeds or gets stuck in the mud - can you get the thing to surface or does it then become a permanent submersible??

Thanks to all in advance

Martin13
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Subculture

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Re: What to Buy ?
« Reply #4 on: November 09, 2007, 11:28:58 am »

I've seen a few Robbe boats built and performing.

Something to bear in mind, is that both a Type VII or a Type XXI were designed as static divers in 1:1 form. They were essentially submersible cruisers, designed to spend the majority of their time on the or close to the surface- the later Type XXI less so in this respect.

As a result, the fullsize prototypes exhibited high freeboard. This is not well suited to a dynamic diving boat, which uses speed and the corresponding downforce from the hydrovanes to submerge. In practice, both these boats need to be ballasted to decks awash to have any hope of successful operation. This does not look at all scale, and even with this lower waterline, either boat requires a considerable lick of speed to stay under the water, which makes operation tricky in smaller ponds.

The Engel type VII is in a completely different class to the Robbe boats. It's a comprehensive static diving kit, with a very highly detailed GRP hull. Unfortunately, the price is in a different league too.

Regarding a boat getting stuck in the mud or weeds/reeds, this is a risk with any submarine. The best advice I can give is to avoid ponds with these types of conditions if at all possible.

Andy
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Martin13

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Re: What to Buy ?
« Reply #5 on: November 09, 2007, 12:43:25 pm »

Thanks Andy, I see your point.

I'm currently building 1/16th scale (6 feet) Brave Borderer MTB and at the current rate of build, the boat will not be in the water for at least 12 months.
In the meantime I would like to build and try out a sub - they look great in the water and I like large models. The intent was to keep the sub mainly as a surface runner. The Robbe U-47 or type XX1 models are not too expensive, can be purchased in Australia, provide some challenge in the building process and would be ideal to learn more about the subs internals etc. with the longer term plan of  purchasing a full static quality sub (engel).

Now, this is the advantage of this forum - I can tap into the vast knowledge bank of the many experienced modellers such as yourself and learn from the experience of others. I appreciate all comments, after all, you guys can save me a lot of headaches (and money)down the track...

More comments please........any info is good info

Martin   O0 O0 O0

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Subculture

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Re: What to Buy ?
« Reply #6 on: November 09, 2007, 03:31:00 pm »

You may not like the looks of it, but there is the Thunder Tiger Neptune SB-1-



Cost is £299 which includes everything you need barring a transmitter and receiver.

It's a full static diver, and I've already seen the kit- an easy build.

Andy
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Mankster

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Re: What to Buy ?
« Reply #7 on: November 09, 2007, 07:47:13 pm »

I don't think it will be too difficult to install a piston tank in one of the Robbe subs and there are plenty of write up on the net on this. Jason from your side of the world did this with his first submarine (Robbe Type VII) as he built it http://magpieyachts.com/  The extra bouyancy will also give you a degree of protection from weeds.

Martin13

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Re: What to Buy ?
« Reply #8 on: November 13, 2007, 08:05:43 am »

Thanks to everybody re your input on types of subs including associated drawbacks.
Think I will put this project on temporary hold as at Easter 2008 their will be running a Sub regatta in Canberra Australia, I believe Task Force 72  sub section will be in attendance. With the Forums input combined with all those subs at Easter (plus the pocket will be much healthier) I should finally make up my mind on which sub.

Thanks again to all - much appreciated

Martin from down Under
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Martin13

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Re: What to Buy ?
« Reply #9 on: November 28, 2007, 10:44:26 pm »

Martin the best thing to do is build the Robbe U-47 as its delivered ( a dynamic diving sub ) to get used to diving a sub and working with the tech-rack. After building it is more than possible to install a piston tank and convert this sub into a static diver.

Re Robbe U-47, as an introduction to sub's, are the Robbe instructions reasonable to follow. I have noticed on other builds eg PT-15, the instructions are woeful and hard to follow...... ??? ??? ???

Any comments

Martin, new to sub's
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Turbulent

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Re: What to Buy ?
« Reply #10 on: November 29, 2007, 06:55:42 am »

My first Sub was a Robbe U47, I converted her to Static Divining by installing a Waterpump system & run her for two years.

Good first boat, but for easy build, have a look at Sheerline, you'd be on the water in a few evenings.

Subculture

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Re: What to Buy ?
« Reply #11 on: November 29, 2007, 10:23:08 am »

The Sheerline subs are in a different category pricewise, however.

That's not to say they're overpriced- you get value for money, but you are looking at £600 minimum to get a Sheerline boat in the water, as their boats start at £525, then you need to add radio etc.

I know high prices keep a lot of people from entering this hobby, so I try and recommend lower priced kits, then when the bug bites............ ;D

Andy


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Martin13

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Re: What to Buy ?
« Reply #12 on: November 29, 2007, 12:59:10 pm »

Thanks Turbulent,

I'm supposed to wait till Easter 2008 prior purchasing a sub but I have a fixation on the type VII, U-47 I like its appearance. Their are many subs on the market and I have spoken with Chris re Sheerline subs but at the moment out of my pocket range (due to the fact I just ordered 1:72 scale Arleigh Burke class DDG).

Andy - I know you are quite experienced in this field, but the bug has hit along with the availability of the Robbe U-47  in Australia and well within my reach of the swmbo's budgetary allowances. Mind you, she doesn't know about the DDG :-X :-X

I'm not concerned at this stage re getting the sub on the water, due to the lack of it >>:-(
The drought has hit us pretty hard and the local areas are only suitable for surface running at the moment and periscope depth is about the limit.
Currently building a large test tank although I told the swmbo it was a "wildlife Pond" (hope it rains so I can fill it), she's none the wiser at the moment. Maybe I should get some water Lillie's to hide it's real purpose in life ::) ::)

My only concern at the moment is with the Robbe instructions. In reading a build it post by Bluebird on the Robbe PT-15, the Robbe instructions on that kit leave a lot to be desired and I was wondering if any submariners had problems with the U-47 set.

When you live this far away from the rest of the world where most of the kits are built, sub's are a very expensive hobby. Freight charges and government duty on kits - the price almost doubles >>:-( >>:-( >>:-(

Martin Down Under
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Sub driver

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Re: What to Buy ?
« Reply #13 on: November 29, 2007, 07:07:29 pm »

Martin13

If I may offer you some of my experience with building BOTH the Robbe U-47 and the U-2540, the instructions come in two parts one is a full picture booklet that shows you each build stage and the other is a full written instruction booklet. Both are easy to read and when used in conjunction with each other are easy to understand to any one that can build kits.

I have converted both to static dive with an Engel tank, you can always mod the boat later for this when funds are available.

If it helps, I will scan a page of both booklets for you so you can see what its all about before paying out your hard earned.

Best regards Sub. :)
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Sub driver

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Re: What to Buy ?
« Reply #14 on: November 29, 2007, 08:02:52 pm »

Martin13, the u-47 has one booklet the photos are in the back instructions in the front. The U2540 has two booklets.

I have tried to post the pics of the books on here but they are two big !!.

Once I have worked out how to get them back from photbucket !!! I will send you the link so you can have a look before you buy

( anyone any ideas how to get photos back from photobucket !!!! and post on here  >:()
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Bunkerbarge

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Re: What to Buy ?
« Reply #15 on: December 07, 2007, 11:06:58 am »

Subculture makes a very good point about the freeboard and one that you need to take into consideration.

I used to have a Robbe U-47 that had a bladder unit which never worked properly but it was ballasted to run at the decks awash level.  I enjoyed practising dynamic diving but very quickly became dissapointed with the fact that you could hardly see any of the model in the water and it had to sail at a significantly greater than scale speed to get it to dive.

Consequently when I decided to make a Revel kit and convert it I made it as a surface runner.  That way I could enjoy seeing it at the correct level as well as put a lot of detail on the tower such as flags, figures etc.  Just to keep your interest going it might even be worth considering making one of these, they are a very nice kit and the detail is superb.

My own goal is the Engle type VII but I am saving up for it slowly out of Ebay sales, I'm about half way there!!  The main reason is not just the superb quality of the kit but the fact that it can sail at the correctly ballasted level until you want to dive it.
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Martin13

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Re: What to Buy ?
« Reply #16 on: December 07, 2007, 11:37:05 am »

Subculture makes a very good point about the freeboard and one that you need to take into consideration.

I used to have a Robbe U-47 that had a bladder unit which never worked properly but it was ballasted to run at the decks awash level.  I enjoyed practising dynamic diving but very quickly became dissapointed with the fact that you could hardly see any of the model in the water and it had to sail at a significantly greater than scale speed to get it to dive.

Consequently when I decided to make a Revel kit and convert it I made it as a surface runner.  That way I could enjoy seeing it at the correct level as well as put a lot of detail on the tower such as flags, figures etc.  Just to keep your interest going it might even be worth considering making one of these, they are a very nice kit and the detail is superb.

My own goal is the Engle type VII but I am saving up for it slowly out of Ebay sales, I'm about half way there!!  The main reason is not just the superb quality of the kit but the fact that it can sail at the correctly ballasted level until you want to dive it.

Thanks Bunkerbarge,

All good points noted. Andy, Sub Driver and the rest of the lads know what they are talking about.

I am going to take their advise and purchase the U-47 as it will be a good learning curve as a first sub, not to mention that it is available here in Australia at an affordable price. I will keep it as a surface runner for now because I am attracted to its appearance. Then when I have learned all about its internals and how they work, I have the option to convert to static dive.

I live in inland Australia, so when I put it into the local river, I'm sure the locals would be impressed - it's a spunky looking sub.

My intention if interest remains, would be to purchase the Engel version in a year or so - unless I win Lotto :angel: :angel:

Thanks Again:
Martin from Doon Under


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dazz

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Re: What to Buy ?
« Reply #17 on: December 07, 2007, 02:21:42 pm »

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