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Still playing around with my Dumas Akula. It has changed a lot since I first got it and has been a lot of fun and a BIG learning curve.
Stage one was to build it as per instructions. :
Did that and it ran well although it did leak water and although I tried several times to stop the drip I had no luck
Stage two was build a new water tight compartment:
That went as planed and was water tight. Still ran very well and only needed 3 channels
(Dynamic diver)
Stage three was to get the front dive planes working :
That also went as planed and although I needed another channel made the boat very controllable. All good so far. Still Dynamic
Stage four was to build another water tight compartment but this time with a ballast tank :
What I planed to do was use 2 air pumps, one to pump air in and the other to pump the air out. Both of the pumps are connected to each other with T pieces to make it a sealed unit which sucked or blew air through the snorkel.
I got the 2 pumps from "Caswell" and they are controlled via a servo and 2 micro switches. It looked good on paper so I gave it a go.
Bath tub tests showed that the hoses can not be crimped or the flow is reduced.
After much playing around with hoses, lead and foam it finally got to a point where I was happy with the way it was working. Sitting nice and high with a full tank of air and just the top of the sail sticking out when the tank is full of water. It takes 40 seconds to fill or empty the ballast tank.
Off to the pond on the next club BBQ run with the Akula under my arm. It ran great on the water and not to bad under the water, seemed a bit harder to drive than before.
After lunch went back to show a fellow club member how clever I was. Blew the ballast and down it went, straight down into the mud.
After I pulled it out and feeling like a fool I discovered that I had hit the bottom several times before lunch (because of the missing paint under the bow) and had leaked a small amount of water, not much but enough to go from the sail just being out of the water to sitting in the mud. The leak was found and a new seal put on the ruder linkage.
I have now fitted an emergency gas cylinder which is capable of filling the ballast 2 1/2 times. So now I have a static diver that comes back up.
Stage 5 is trying to get it to look a bit better. The rear tail on the Akula didn't do a thing for me and hindered control when under water, so off it came and now it is a Alfa look a like
Stage one was to build it as per instructions. :
Did that and it ran well although it did leak water and although I tried several times to stop the drip I had no luck
Stage two was build a new water tight compartment:
That went as planed and was water tight. Still ran very well and only needed 3 channels
(Dynamic diver)
Stage three was to get the front dive planes working :
That also went as planed and although I needed another channel made the boat very controllable. All good so far. Still Dynamic
Stage four was to build another water tight compartment but this time with a ballast tank :
What I planed to do was use 2 air pumps, one to pump air in and the other to pump the air out. Both of the pumps are connected to each other with T pieces to make it a sealed unit which sucked or blew air through the snorkel.
I got the 2 pumps from "Caswell" and they are controlled via a servo and 2 micro switches. It looked good on paper so I gave it a go.
Bath tub tests showed that the hoses can not be crimped or the flow is reduced.
After much playing around with hoses, lead and foam it finally got to a point where I was happy with the way it was working. Sitting nice and high with a full tank of air and just the top of the sail sticking out when the tank is full of water. It takes 40 seconds to fill or empty the ballast tank.
Off to the pond on the next club BBQ run with the Akula under my arm. It ran great on the water and not to bad under the water, seemed a bit harder to drive than before.
After lunch went back to show a fellow club member how clever I was. Blew the ballast and down it went, straight down into the mud.
After I pulled it out and feeling like a fool I discovered that I had hit the bottom several times before lunch (because of the missing paint under the bow) and had leaked a small amount of water, not much but enough to go from the sail just being out of the water to sitting in the mud. The leak was found and a new seal put on the ruder linkage.
I have now fitted an emergency gas cylinder which is capable of filling the ballast 2 1/2 times. So now I have a static diver that comes back up.
Stage 5 is trying to get it to look a bit better. The rear tail on the Akula didn't do a thing for me and hindered control when under water, so off it came and now it is a Alfa look a like
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