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wilsteadt
Joined: 15 May 2010 Posts: 27
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Posted: Thu Dec 12, 2013 11:33 pm Post subject: Berkeley/AT cavitation |
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I am building a 12-13' boat with a 13* bottom and have a couple of pumps that I can use.
I have a 752 that still has the flapper steering. It is in decent shape but I have never worked on or know much about the multistagepmps. I would like to use it but am a little hesitant.
I also have a AT 309 in good shape that I can use also. I know the AT/Berkeley style pumps very well. Parts are everywhere down here (southwest US) and I have a trim nozzle, stomp grate, and extra parts.
My concern is cavitation with the AT. I have a 20' boat with a 6* bottom and an AT that cavitates easily. It works great on flat water but not so well when there is chop much less rapids.
I am hoping that the deeper Vee helps with cavitation but I was wondering what you guys do. The Berkeley style pumps seem popular with river racing so they must work in rapids.
In my new boat What can I do to make the AT work and not cavitate? How well do they deal with cavitation for you guys?
Matt |
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ALEX
Joined: 02 Aug 2005 Posts: 176 Location: red deer
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Posted: Fri Dec 13, 2013 7:12 pm Post subject: |
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The at pump will work well with the 13 deg bottoms
Quiet,fast and good steering
The antique Hamilton with flapper steering deflects the water to steer and cuts off the thrust;also noisy and takes up room in the boat
You did not say which motor you have.
The 2 stage only works with a v6
And parts...especially impellers are expensive compared to AT |
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wilsteadt
Joined: 15 May 2010 Posts: 27
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Posted: Fri Dec 13, 2013 9:33 pm Post subject: |
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I have an iron 5.7 with 260hp that i will be starting with. I am hoping to get a good running subaru that can put out 200hp or so going this summer or next winter.
I just typed a long reply that basically said: I really like the at pump i have but i cant do any whitewater in it because it cavitates so badly. It cavitates because of the shape of the bottom so I can't make an apples to apples comparison. And I have never use a Hamilton on any whitewater.
I dont want to be limited in this new boat so i am willing to use and accept the limitations of the old hamilton so i can run some white water. I would rather use the AT if I can get some good feed back about their ability to go through mildly aerated water.
Could these boats make it through these rapids going slowly or is it their momentum that gets them through? http://www.youtube.com/watch?v=qIDr2nF-RnM
I know I would have a hard time with big whitewater but how far have you pushed your boats.
Any Videos would be appreciated of boats with AT style pumps running any whitewater.
The simplicity, weight, my knowledge of them and their durability are the main reasons I want to use my AT.
Thanks, Matt. |
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RPM
Joined: 17 Dec 2006 Posts: 189 Location: Nechako
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Posted: Sat Dec 14, 2013 11:05 pm Post subject: |
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don't loose sleep over if your AT pump is going to cavitate like your 20' 6* boat . your 13*, 13' boat will load the pump waaayy better , especially with that lump of a 350 your using . pick the pump that best suits the performace you are wanting most . basically i'd compare the 2 stage to a 4x4 and it could be set-up to work fine with a 350 in a 13' , the AT will give up holeshot , acceleration , and a lot of reverse for a little more room , top speed and quieter cruising . the 2 stage will clear itself of debris better and wouldn't have to have an easyclean which I'd say is a must have with the mixed flow pumps . _________________ Rick's Precision Machine
Prince George B.C.
Machining - Welding - Repairs |
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wilsteadt
Joined: 15 May 2010 Posts: 27
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Posted: Sun Dec 15, 2013 12:27 am Post subject: |
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Thanks for the replys. I think that the 2 stage will be better for most of what I want to do but I am much more comfortable with the Berkeley style pumps. There will be no learning curve and I have extra parts including a stomp grate and a trim nozzle. I also have a htr ll nozzle and reverse I can use if I feel the need.
The 752 might be plug and play in my boat but I got it out of an old boat that had been sitting for years. It might be worth the effort to make it work but to get a trim nozzle and a decent (non flapper) steering will be expensive. I did try to pull one of impellers and it didn't budge. Getting it working might be a fight.
I also have a 753 that seems to be in great shape but it was set up for a big block olds so I would probably need to start with a different set of impellers right off.
Right now I am going with the AT but I change my mind often and may change it again before it ends up in the boat.
Thanks again and keep the replys coming and I still want to see videos (I just like watching them anyways)
Matt
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