Audeen Jetpump Help

Questions about modifying a design

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Richard9
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Joined: Sat Nov 10, 2018 4:32 am

Audeen Jetpump Help

Post by Richard9 » Sat Nov 10, 2018 4:37 am

We have a “family” boat with a very high nostalgic value among family members built in the very early 60’s that was converted to a Berkley pump with a jack shaft and split fuel tanks in the stern during the 80’s.
Boat runs and handles great however the pump has trouble picking up water when started and occasionally losses suction at low speed and when going in reverse which is due to the shallow draft of a flat bottom. The only way to prevent this is having full fuel tanks of about 30 gallons total and two adults in the stern seats.
My thoughts are to slide the engine back to the pump basically turning it from a mid to a stern engine to keep the pump deeper in the water and then construct a bench seat across at the old engine location with the fuel tank mounted somewhere under the new seat or even farther forward.
My thinking is moving an 800 lb engine to the stern and off setting some of that with two or three adults and a fuel tank would give me added stern weight without to much of a negative effect on plane. Also thinking a place diverter would help if it seems to stern heavy on plane.
Looking for comments and thoughts or other possible solutions.

PS Dumping the boat is not an option since this craft is about to teach its fourth generation to ski, wake board and learn the basics of boat handling and water safety

Thanks

Richard

Cyclone
Posts: 62
Joined: Sun Jan 08, 2012 7:26 pm
Location: Barrie, Ontario

Re: Audeen Jetpump Help

Post by Cyclone » Sat Nov 10, 2018 12:49 pm

I do not have any experience with jet drives. Reading your post, it sounds like the pump starving issues at low speed and in reverse has always been present with the current configuration of the boat. I would be concerned about moving the engine too far from the location where the boat design specifies. When you are at higher speeds/planing I think the intake might be higher in the water then when the boat is at rest or at low speed, but at higher speeds the angle of the hull in the water and the movement is forcing water into the intake. As you have said moving weight aft to change the center of gravity of the boat to sink the stern mounted jet pump lower in the water will improve the pump function for low hull speeds. If it was possible to lower the position the pump is mounted in the hull this would give the same benefit without having to change the center of gravity of the boat. Not sure if there is some sort of spacer between the intake surface of the pump and the hull that could be reduced? If this was possible then it would involve some changes to the position of the jet drive where it exits the hull as well as adjusting the height and/or angle of the motor. Maybe some lowering of the pump in the hull and moving the engine slightly to stern? Just my thoughts.

283
Posts: 115
Joined: Mon Oct 23, 2017 10:14 am
Location: Maine

Re: Audeen Jetpump Help

Post by 283 » Mon Nov 12, 2018 5:44 am

Have you tried changing the intake grate?

I don’t know much about them but I know there are many different designs available for less then a couple hundred bucks... might be worth researching to see if one would help your situation.

https://www.berkeleyjet.com/c-648-loader-scoops.aspx
Mike

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hoodman
Posts: 1902
Joined: Thu Nov 10, 2011 8:48 am
Location: Lafayette, IN

Re: Audeen Jetpump Help

Post by hoodman » Mon Nov 12, 2018 8:54 am

Seems like moving the engine is asking for trouble. These boats are designed to have the weight of the engine in a certain spot. If you move it you can really upset things.
Matt

Building a Geronimo......!
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