Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: chale02 on January 18, 2009, 09:06:22 pm

Title: pumps can thay be made to self prime
Post by: chale02 on January 18, 2009, 09:06:22 pm
Hi all new to forum so be gentel with me don't no alot about model boats i use mine for fishing the baitboat i have runs on pumps and you have to prime them each time you put it into water By this i mean put boat into water lift back of boat clear of water press the on button till water flows out of pumps If you just try and put in water without doing this boat will not move think it is like air locked All microcats do this apart From new Mk2 which thay have sorted this problem out Is there any way i could get pumps to self prime Was thinking drilling a hole in side of pump mounting a tube to it with a one way valve to let air out when you put boat into water Could this work or am i totally wrong i what iam thinking Thanks again for replies any help would be great

Chris 
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 18, 2009, 09:08:25 pm
Been looking around on web and i think ive found pumps what are in my baitboat think thay are these if this helps anybody
http://www.jabscoshop.com/article.asp?ls=&v=CE3D7FD4FE2242C49619E0A929EB8B9F&override=1&title=jabscoshop%3A-About+Submersible+Pumps

Title: Re: pumps can thay be made to self prime
Post by: Martin (Admin) on January 18, 2009, 09:31:14 pm
How have they sorted the problem on the Mk2 ?
( What's a Microcat? )
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 18, 2009, 09:35:29 pm
Not sure how thay sorted it on mk2 microcat is made by angling technics for carp fishing Will put up a link so people can c what it is
Title: Re: pumps can thay be made to self prime
Post by: Stavros on January 18, 2009, 09:36:11 pm
Martin a Micro cat is as the name suggests a catamaran bait boat.Right then with regards to those pumps I have used them a lot as bilge pumps in Yachts and speed boats and have never had top prime them,they usually self prime


Specially for you Martin   http://www.anglingtechnicsbaitboats.co.uk/

Stavros
Title: Re: pumps can thay be made to self prime
Post by: Peter Fitness on January 18, 2009, 09:45:28 pm
I've never seen one of those - what WILL they think of next  :o

Peter.
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 18, 2009, 09:48:11 pm
Dont no if it is how thay are mounted in boat Thay are mounted at 45 deg The link that i posted for pumps mine have blue bottom piece missing as thay are bolted though hull with a weed guard on Will try and post some pictures of it if that will help anybody if i can work out how to post them

thanks for all your help

Chris
Title: Re: pumps can thay be made to self prime
Post by: hopeitfloats on January 19, 2009, 07:25:48 am
hi chris. as long as the impellor is covered in water your pump should self prime but i have had quite a bit to do with larger bilge type pumps and sometimes the air can get trapped.  some of the models i service actually do have a hole drilled in them to let the air out but they work best if the hole is drilled above the outlet. our ones just squirt water out the hole when its primed. ie- no check valve but if you need one they can be made.  you need something like a tube with a ball in it. the basic principal works on the air passes around the ball but when water pressure hits it the ball lifts up and blocks the outlet hole.
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 19, 2009, 09:13:46 pm
hi all ive taken a photo of pumps if that will help anybody better
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 19, 2009, 09:43:30 pm
more photos as ask for by martin
Title: Re: pumps can thay be made to self prime
Post by: Martin (Admin) on January 19, 2009, 09:52:12 pm
To me it looks like the pumps are too high out of the water......
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 19, 2009, 10:21:13 pm
two more photos of underside this may help a bit more
Title: Re: pumps can thay be made to self prime
Post by: nick_75au on January 28, 2009, 07:53:30 am
The pumps wont prime on that angle because the inlet is at the same level as the outlet giving room for a nice fat air bubble in the impeller. The only way you are going to get it to self prime is a bleed line at the highest point of the cavity of the pump. This needs a hose attached to above the waterline and no dips in the line. When the pump runs some water will discharge out of the hose as it will be on the pressure side of the pump. Hopefully my simple pic will explain.
Nick
Title: Re: pumps can thay be made to self prime
Post by: chale02 on January 30, 2009, 05:41:10 pm
thanks for reply nick thats what ive been looking for will give it a go thanks again

chris
Title: Re: pumps can thay be made to self prime
Post by: grovsey on January 31, 2009, 07:18:07 am
hi all
i am looking at making my second boat this time with pumps instead of propeller,i noticed in the pic there is 4 pumps is ths for forward and reverse??
will i have to have 2 electronic speed controllers now to do this ?
also does anyone know where i can get a hulll from like in the pic there was some on ebaY but he has stopped selling them for some reason,maybe someone complained from anglingtechnics
cheers
          ian
Title: Re: pumps can thay be made to self prime
Post by: toesupwa on January 31, 2009, 07:26:00 am
1/ i noticed in the pic there is 4 pumps is ths for forward and reverse??
2/ will i have to have 2 electronic speed controllers now to do this ?
3/ also does anyone know where i can get a hulll from like in the pic

1/ Yes
2/ If you want them to run independantly, you will need 4 ESC's
3/ Have you tried asking Anglingtechnics?
Title: Re: pumps can thay be made to self prime
Post by: grovsey on January 31, 2009, 07:32:22 am
4 spped controlers this is getting expencive now as there not cheap.
i seen these on ebay,anyone know who is making them
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=380099885959&ssPageName=STRK:MEWA:IT&ih=025
Title: Re: pumps can thay be made to self prime
Post by: toesupwa on January 31, 2009, 03:22:05 pm

i seen these on ebay,anyone know who is making them
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=380099885959&ssPageName=STRK:MEWA:IT&ih=025

Have you tried asking the seller?.
Title: Re: pumps can thay be made to self prime
Post by: grovsey on January 31, 2009, 04:14:55 pm
sent him about 5 emails and no reply
Title: Re: pumps can thay be made to self prime
Post by: nick_75au on February 01, 2009, 10:40:55 am
You could get away with two servos and some switches, will only give you on-off control on each pump but for the bait boat I don't think that is a problem.
The switches need to be single pole double throw or individual micro-switches for each pump. Connect all negative wires to the battery neg, a positive to the centre of both switches and each positive of the pumps to an outside contact on each switch. A little mucking about with servo links and it will go.

Or simpler 2 ACTion relay type units will eliminate servos and linkages.

Nick