Alumacraft MV1448 Seadoo IB jet, Still jetting

Ranchero50

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[url=https://www.tinboats.net/forum/viewtopic.php?p=339501#p339501 said:
Brine » 23 Jan 2014, 17:37[/url]"]Least we forget... One of the coolest damn builds on here :USA1:

And it's still going. :shock:

Some winter I'm actually going to put carpet in it. This winter it sat outside in the garden plot with my cover on waiting patiently and it's still waiting...

I did pop the cover last week and everything is dry and looks / smells good. Motor turned over by hand too so it's just a waiting game for the water to warm up.
 

Ranchero50

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Getting closer to water time again. Took a trim in my truck to get the stickers for the boat. I forgot to mail them in 'again' and thought I might actually get on the water this week. And then it rained again...

New tow rig. A '71 F-350 with a 6bt for power.
DSC02123_zps4bfd21d7.jpg~original
 

Ranchero50

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Actually it's like the boat, just took time to find the parts and then fit them together. I'm pretty sure I have less than $4k into it, maybe $3k. Engine is a '93 6bt, tranny a '94 47rh. Rear a mid 90's 10.25" Sterling, all swapped for work. Cab was from my free '71 F250, '70 F350 was $400, sold the cab for that. Aluminum welders bed was $400.

DSC02006_zps1e466650.jpg~original
 

typed by ben

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oh. the way you worded it i thought you bought it. i had the feeling you wouldnt have bought it unless it was a good deal. anything with a cummins is demanding top dollar last few years, im sure you are aware

my dad had a '68 contractor special with a 3 on the tree and a 352 until i was about 15. it was beat to shit and when he traded it in they gave him $50. as we were waiting for the new truck to be detailed a flatbed loaded her up :cry: i was nearly born in that truck but my dad had no trouble letting it go lol.
 

Ranchero50

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So here we are, ready for another season. Finally managed to get all the planets aligned and got the boat in the water for the first time this year. Boat fired up fine in the garage, a bit smokey and rough at first but it smoothed out after a minute or two of fast idling.

DSC02140_zps032c4942.jpg~original


DSC02139_zps6924c307.jpg~original


I did get new decals for it and painted the engine cover and some other bits with the plastic paint. So far I'm really happy with how it has lasted but with the texture it does get dirty quickly. Cruised up to the islands and picked up a bunch of 13" class smallies out of the eddies. Saw a bald eagle, a beaver and a deer. The boat was sluggish going up river, figured I sucked up some trash at the ramp because I left it idle for a while to make sure the cooling loops were open. Coming back down, it was back to it's normal smooth and fast.
 

He Reigns

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I'm starting to feel bad, I thought a multi colored jet jon was the way to go around here.

Are you using a product simular to plastidip? I have been kicking around the idea for parts of my boat.
 

Ranchero50

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Mine is multicolored too. Everything close to the water is camo'd, blues, brown, green, black, reds ghosted over with tan so it doesn't scare the fish away. :)

The paint is just some $2 clearance rack special stuff for painting plastic lawn chairs. I bought two cases a couple years ago and still have 10 cans. Rustoleum special textured plastic paint, color sandstone.
 

Brine

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Glad to hear you made it on the water.

Nice tow rig 8)
 

Ranchero50

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Oh man, what a fun evening. :)

For most of this season and part of last season the boat just didn't seem to perform like it should. My fooling around video showed some of the problems with cavitation on launch that's been getting worse as time went on. This afternoon after welding holes in BigTerps jet boat I really looked over my pump and found that the bellows for the drive shaft ceramic seal was stiff and the seal was not seating very stiffly. I know that's a common place to ingest air into the pump cavity. So, loosened the hose clamp and scootched bellows a bit tighter against the seal ring.

Kid passed on going fishing to go buy boots so I was solo on the river. The boat was alive with power and really loaded the pump instantly launching the boat out of the water like it used to before I added the pods. Before it would hesitate and cavitate launching slowly in a very flat attitude. Speedo showed mid 30's at 4k and a max of 45 which I hadn't seen in a while. So either the kid is overloading the hull or I had a problem...

I did get to fish a good bit, caught a 18" channel cat on my fire tiger rapala and a ton of oddball bass on it or my black jitterbug at dusk. As usual, the mayflies were out in force and without a bug catcher sitting up front I was forced to wear my sun glasses coming down river. I'm sure the bow is speckled because my glasses sure are.

So, since the enthusiasm is back I'm going to try and get another video up of it running and maybe the launch and recovery sequence.
 

NewRiverDan1

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Ranchero50,

This was an awesome project I've been looking at for a while. Really motivated me to build something of my own. I started with a 1648 tracker and a Kawasaki 1100. Its been alot of fun and I'm just about finished. But have some thoughts for hull protection, your in a similar area/river as myself, what do you do to protect your hull from occasional rock abrasions? I am considering a bed liner product with a smooth application. What are your thoughts?
 

JasonD

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Excellent build! I have a 1448 and 580 motor I'm about to pair together. Mine doesn't have the variable trim and trying to figure out how to mount the jet. Do you know about what angle in relation to the bottom of the hull gives you the best performance? Can't wait to get cutting on mine and will be utilizing much of your designs. Thank you for the write up!
 

JasonD

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Can't thank you enough for putting this build up. I'm currently working on one myself and this helps alot. Was wondering if there was any chance I could get you to mill the rear plate that holds the jet? How much to run the part? I have everything I could need to build my jet Jon except for that cnc mill of course.

Jason
 

Ranchero50

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Hey guys, sorry I haven't been paying attention to this thread. NewRiverDan1, per the bottom protection, I just try to avoid the hard stuff on the bottom. I really want to put steel flex on the outer hull some winter and see how that does.

JasonD for the pump mounting plate, 90` to the bottom of the hull and high enough that you can maintain no drive line misalignment. On mine the bottom of the pump was @ 1/4" above the bottom of the hull. For fabbing the plate, I could do it but you'd need to supply the 3/4" aluminum plate. Per the trim, I think you can add the trim nozzle setup to a non trimmed pump 140mm pump without issue. You should do some research onto that.
 

JasonD

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Ranchero50 said:
Hey guys, sorry I haven't been paying attention to this thread. NewRiverDan1, per the bottom protection, I just try to avoid the hard stuff on the bottom. I really want to put steel flex on the outer hull some winter and see how that does.

JasonD for the pump mounting plate, 90` to the bottom of the hull and high enough that you can maintain no drive line misalignment. On mine the bottom of the pump was @ 1/4" above the bottom of the hull. For fabbing the plate, I could do it but you'd need to supply the 3/4" aluminum plate. Per the trim, I think you can add the trim nozzle setup to a non trimmed pump 140mm pump without issue. You should do some research onto that.

Thanks for the info on your set up. Plan is right now to mount the pump where it needs to be and then use that to align my motor mounts. I'm figuring around some ideas to make up a plate to hold the pump but might work something out with you in the end. I've priced a few VTS I've seen on ebay and I plan to get the rig running first and look at retro fitting later. This thread is such a great resource, thanks
 

Ranchero50

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The curse of the pump mount flange was the pump had a step on the front edge that I needed a recess for, thus the 3/4" plate. That also gave me a solid point to weld the pump inlet to and over the last couple years has worked very well. Honestly, I'm surprised this boat has done as well as it has because for most the original pump work my shielding gas hose was clogged with mud dauber nests and those welds are rather porous. :)

When you mount your pump you want the axis of thrust with the trim set neutral to match the axis of travel with the boat running flat out. If it's down the nose will plow and really handle like a dog. If it's too high you'll either porpoise or run slow as your thrust isn't impinging on the standing water. With the trim I just bump it up until it slows and then drop it back a little bit. The motor tone changes and the boat scoots along a couple MPH faster. Of course it's not shooting a rooster tail then either.

Also when you do your pump inlet, try to minimize the tunnel size and length. At low speed you really need a lot of volume or it'll cavitate. At high speed you don't need as much volume as the opening will create drag. It took me two shots to get one that worked well and I think the sport jet grill helped make the design parameters that would work with the 140mm pump. Along with the size of the opening, you really want the opening as far back as is practical and try to allow passages between the strakes and the side of the opening for air to escape. With a mod V or straight flat bottom you will ingest air and if you can't get it to bypass the pump you will cavitate and have troubles. My spoon 'cured' my problem unless I'm in while caps. Oh yeah, when the opening is close to the transom it's a whole lot easier to clean too.

Good luck and post a link to your build thread. I tried to describe what and why I was doing stuff on this thread to help others and love to see how they did stuff as well.

Jamie
 

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I will post a link and share as well. You developed a great build but worth that little detail of having a CNC just sitting in your garage it puts it at a level out of reach to most people. I have an idea to incorporate the ride plate into the build to deal with the pesky step on the flange. While I would much rather have your pump plate this, hopefully, simplifies the build and you don't have to eat the cost of 3/4" aluminum plate :eek: Plan to keep this as a rig that can be built with minimal specialized equipment. As for my intake I am currently working on mimicking the tunnel shape of the ski it came off of. Thought being that is what seadoo decided the optimum water flow needed for the pump. Right? Who knows but it at least sounds good to me lol. This build intrigues me on the challenge of building such a vessel and trying to do it for minimal cost. Paid $100 for the seadoo, traded an old canoe for a 1448 monark boat and only out a few parts to get the ski running so far. I won't clog your thread up with my build but will make sure to update along the way, have a thread currently in another forum.
 

Ranchero50

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Welp, this is officially ridiculous... I still haven't splashed my boat yet this year. I'm ready to and want oo but mother nature is pouring on us. Heck, my garden even drowned.

Just venting.
 
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