1998 Dauntless 15 Livewell Scoop Orientation

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Dauntlessbob
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1998 Dauntless 15 Livewell Scoop Orientation

Postby Dauntlessbob » Tue May 17, 2022 11:40 am

[This Thread has been moved to THE GAM from the INTRODUCTION TO THE FORUM SOFTWARE forum. Please do not use the INTRODUCTION TO THE FORUM SOFTWARE forum to post boating questions--Moderator]

Q1: what was the factory orientation of the water pick-up scoop on a 1998 DAUNTLESS 15, that is, did the scoop opening point forward or astern?

Scoop.JPG
Fig. 1. Boston Whaler factory drawing showing details of the live well system. Note at CALLOUT 59 the orientation of the scoop opening is forward.
Scoop.JPG (48.31 KiB) Viewed 905 times


FIgure 1 above shows the scoop facing forward. That probably answers the question but not sure if that is just a notional diagram.

BACK STORY
I have a 1998 Dauntless 15. My boat has the factory livewell option. There is a small sump at starboard aft where the livewell pump is installed; the livewell is installed in the stern bench seat on port side. There is no seacock valve in the plumbing design--no room in the small sump.

I replaced the failed livewell pump this winter. I got sidetracked, and now I am just putting it all back together.

I can't remember for sure if the hull inlet strainer scoop slots should face forward or aft. I'm thinking the slots were facing forward, but can't remember for sure. I understand that forward facing will create pressure in the pump line, and rearward facing will create suction.

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Phil T
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Re: 1998 Dauntless 15 Livewell Scoop

Postby Phil T » Tue May 17, 2022 12:26 pm

Look at the screw holes in the hull.

I would say the slots face forward.
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Dauntlessbob
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Re: 1998 Dauntless 15 Livewell Scoop

Postby Dauntlessbob » Tue May 17, 2022 12:40 pm

Thanks but with this scoop the screw holes are symmetrical so things line up whether I hold it up to the hull facing fore or aft.

jimh
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Re: 1998 Dauntless 15 Livewell Scoop Orientation

Postby jimh » Thu May 19, 2022 10:44 am

I don't understand the basis for disqualification of the Boston Whaler factory drawing as incorrectly showing the orientation of the water pickup scoop inlet as facing forward. The natural orientation of a water pickup scoop would be to promote inflow of water when the boat was underway with forward motion. The drawing clearly shows that orientation. I doubt Boston Whaler would have gone to the trouble to illustrate the installation of the scoop in the WRONG direction. These drawings are probably created by engineering and given to production to show them how to install components.

What further evidence do you need to overcome your reluctance to rely on the drawing and the general assumption of how a pickup scoop works?

The only odd element of the drawing in Figure 1 is the screw fastener orientation at CALLOUT 65. The drawing seems to suggest the screw fastener is thread into the scoop from above.

Also, if the pump at CALLOUT 61 is a centrifugal pump, then the pump will not be able to lift water to its input port. Unless the pump inlet is located below the waterline of the boat when the boat is at rest, the pump will depend on water being pushed uphill by the scoop and the forward motion of the boat to get to the inlet of the pump. After that the pump can move the water uphill to the well.

Dauntlessbob
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Re: 1998 Dauntless 15 Livewell Scoop Orientation

Postby Dauntlessbob » Thu May 19, 2022 1:54 pm

First, thanks for taking time to give me your thoughts and respond to my post.

The drawing has other details which are not exactly representative of the actual equipment on my boat. For example, the drawing shows the pump being held down to the hull with some screws in addition to the thru-hull nut which does not match my hardware and the orientation of the pump is turned 90 degrees on the drawing. You noticed the screws for the scoop being shown as being installed from above. Being an engineer myself, I've seen situations where simplified drawings that intend to show the component parts for service manuals or end users are created which are different from the detailed assembly drawing used in the factory to guide manufacturing. The little inaccuracies just made me doubt that the drawing was intended to be used as an assembly guide.

I was looking for someone who might have a boat with the factory installation who could know how it was actually assembled.

The pump is in a sump so it's below the waterline so it will pump water regard of the scoop orientation when the boat is at rest on the water. If I install the scoop facing forward, when running on plane I expect that scoop will generate pressure such that water will flow to the livewell whether the pump is on or off. If I face it aft, vacuum will develop when moving at speed which will suck the livewell feed hose dry and I expect that water will not move to the livewell regardless of whether the pump is on or off.

I agree with your tendency to let good logic rule the day when you said "...the general assumption of how a pickup scoop works". I think I will install the scoop facing forward and then see what kind of flow I get to the livewell at speed. As long as the livewell drain flow is faster than the feed flow, there should be no problem...just make sure the feed hose clamps are tight.

Dauntlessbob
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Location: Washington

Re: 1998 Dauntless 15 Livewell Scoop Orientation

Postby Dauntlessbob » Tue May 24, 2022 12:59 pm

Thought I would close to loop on this topic...I installed the scoop facing forward and water tested the boat. Turns out that, even with the scoop facing forward, when the boat is on plane and moving 25 to 30 knots not enough water pressure is generated by the scoop to force water flow through the pump and up through the hose to the livewell without the pump running.

I also figured out that there is a flow control valve (which doesn't really look like a valve) on the end of the spray head fitting that flows water into the tank. The options drawing calls it a "Spray Head". Couldn't figure out why I could hear the pump running but no flow to the tank? I eventually figured that I was looking at a valve and that I needed to open it.

Everything works great now.
Attachments
Sprayer.JPG
Sprayer.JPG (17.39 KiB) Viewed 826 times
Livewell sprayer.JPG
Livewell sprayer.JPG (41.3 KiB) Viewed 826 times