2003 Duracraft 1648 bass

[Mark v]

Hey y’all, I’m new to the site and am looking for some general guidance.

I just bought a 2003 Duracraft 1648 bass with a 70 hp Nissan. It’s a really sweet rig and makes me miss my 21’ bass boat not at all.

I only had a brief on the water test with it as it was late, the lake was unfamiliar and large, and big boats were throwing rollers our way.

My brief driving stint was completely embarrassing. I couldn’t get it on plane to save my life. I had a 21’ Gambler with a 200 promax before… I can drive a boat, but it sure didn’t look like it that day.

With my gambler, I’d trim it all the way in, hit it, jump out of the hole, trim it out and I’m flying.

This boat didn’t like any of that. It was late and I was now very frustrated so I gave the owner back the wheel.

Please tell me how to drive this thing.

#2. What sort of speed should I be seeing? I didn’t have any kind of speed app going but at 5400, it didn’t feel any faster than 30. 35 tops.
Boat empty except for about 450# of people. I’m not expecting a rocket, but it felt like slip numbers were way high. There was still plenty of motor left even at 5400 so I don’t think it’s a motor issue.

 

[flatheadsteve]

So many factors at play but I would think a heavy 1648 like that with a 70hp should see around 40mph maybe a little more. Looks like maybe a 3deg mod v hull so it's not going to be as fast as a deeper v . Download a GPS speedometer on your phone and get a good number and you'll have a better idea. If you really suspect something isnt right you could check for water logged foam. If speed doesn't seem to increase with rpm could be a spun hub. But those are wild guesses untill you know for sure your top speed and rpm.

 

[Mark v]

Thanks for that.

I’ve had a chance to take a closer look and all three blades look like a rock chewed a nice flat spot in them and folded a 2 mm lip over the front of the blade.

1. Is it repairable?
2. How bad would it kill performance?

Thankfully the prop shaft still spins true

 

[flatheadsteve]

Thanks for that.

I’ve had a chance to take a closer look and all three blades look like a rock chewed a nice flat spot in them and folded a 2 mm lip over the front of the blade.

1. Is it repairable?
2. How bad would it kill performance?

Thankfully the prop shaft still spins true

That would certainly hurt performance how much I don't know. Take the prop into a shop sometimes they can be repaired.

 

[wmk0002]

Just my 0.02, but I've never noticed much difference between trimming down an aluminum boat like that for holeshot. I typically set it and forget for most of the day, the exception being tweaking the trim at WOT for the smoothest ride since very slight changes in chop can have a big impact on a boat like that.

 

[Mark v]

Reviving my old thread. I got my prop fixed and the guy did a phenomenal job. He said he added a bit of cup as well. He does factory warranty work for all the major mfg so his work is trustworthy.

My current issue is setup related. At 34 ish, it starts to get squirrelly and begins porpoising with still over 1,000 rpm left to go. Trimming back down restores the boat to its normal ride. I’ve noticed at just about any speed that it wants to porpoise if trim is just a fraction too aggressive. It has cable steering and is oddly light as a feather at speed, virtually nonexistent torque steering and I can drive it with my index finger if I so chose to do so, but obviously never will. Feels very odd.

I’m guessing the motor is set too deep? Bottom of the boat to prop shaft is roughly 8”, but I’ll have to double check. Motor is set on the deepest most setting. I’ve gone to lithium batteries for my electronics but still have a lead cell for the cranking. I have an 11 gallon fuel tank but it’s mounted longitudinally.. not ideal but works for now.

I swapped my trolling motor for a Garmin force which added 40 lbs to the bow. No improvement in the porpoising.

This is my first go with a boat like this so it’s a new journey as to what I should be looking for.

My lofty goal is 50 mph with a medium load. This motor is an ecu and gear case swap away from 20 more HP. I have the factory service manual. That’s literally it.

I don’t see how I would be able to shift weight from back to front and I will play with motor height, but besides this, what else should I be doing?

Thanks for your time.

 

[FuzzyGrub]

Yes, you will need to experiment with motor height. Make sure your hull doesn’t have a hook in it. Also, look at tabs to see if they can help you. I have used smart tabs to control porpoising and chine walk on a bowrider. Not sure how effectively they will work on a 1648 Jon boat.

 

[flatheadsteve]

A jack plate would give you some setback and allow you to fine tune that motor height. Manual jack plates are much cheaper than hydraulic but can't be adjusted on the fly.

 

[Mark v]

Yes, you will need to experiment with motor height. Make sure your hull doesn’t have a hook in it. Also, look at tabs to see if they can help you. I have used smart tabs to control porpoising and chine walk on a bowrider. Not sure how effectively they will work on a 1648 Jon boat.

How do I look for the hook?

 

[FuzzyGrub]

How do I look for the hook?

Examine the bottom just forward of the transom. Should be flat and straight. Usually caused by roller trailers or too short of bunks.

 

[airshot]

Start out with a proper check of motor height....get a straight edge on the bottom if the hull and slide it back and adjust the motor tilt until the cav plate is parallel to the bottom. Is the cav plate above, below or right at the hull bottom?
It should be at the bottom or "slightly" over or under. That is your starting point! Get the prop fixed or replaced before more testing. Once the prop issue is settled, you can now get a good read on your setup, so intelligent adjustments can be made.