Some questions about outboard jet hull sizes

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jsmoody

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I'm starting my search for my next boat. My specific needs are for it to be big enough with enough HP to carry 5 or 6 adults. I've gotten to the point where the only boating we do is in one river up and down a 20 or 30 mile stretch and it's just joy riding really. There are some stretches of river that get down to 6 or 8 inches in the summer and I need to be able to get upriver when it's like that. I've had and been in lots of jon, but I have no experience with jet outboards. Bottom sand and gravel flats. I've done a lot of looking and reading about hull sizes but I have some questions about the differences between them and their characteristics. It is my understanding that a given jet size will only plane a certain weight, but how do boats of the same weight that are different widths or lengths affect it? For instance what would be the difference between how an 1860 or a 2052 would handle? Maybe a 1760? I see a lot of boats that are 1752 or 1756 with a 60/40 jet. Shouldn't that be underpowered? Would like to narrow down what I "should" be looking for.
 
If you plan on hauling 5 or 6 people all the time you will want a wide hull, preferably 60" bottom or even 70". 1860 would be ideal. Only issue with a bigger boat is you are going to need a bigger engine. The narrower a boat is the deeper in the water it will run. A wider hull will displace more water and will ride higher while on plane if you have enough power to push it. For an 1860 bare minimum hp for that load would be a 115/80 and it is going to struggle when you load it down. I would recommend at least a 150/105, it would easily plane it out and carry a load much better. I was running a 250 Pro XS on my 1860, it is a commercial hull though with no coast guard weight or hp limits. For insurance purposes and liability reasons you will want to stay within the limits on the boat. Most 1860's have a limit of 150 hp or less on the tag. I am ordering a new 2060 to get a commercial hull this time because they can't build one under 20 in a commercial rating, government regulations.

Depends on how much you want to spend and if you run where there are any hp limits. A lot of boats around my area run 60/40 due to the hp limits in the Ozark National Scenic Riverways.

To answer your question a little better. A narrower hull will be faster. Adding length will increase weight capacity without affecting speed. A wider hull will easily carry more weight, but will be a bit slower due to pushing more water. A wider hull will also plane easier with a heavier load.
 
Good info thanks. So considering that i guess i need to be somewhere between an 1860 and a 2070. I dont much want anything bigger than that, and would prefer to stay closer to 18 feet if possible. Ive got a local boat builder i would really like to work with on it and he builds some really big and wide flats for oyster barges and such but i will need to try and trim the fat somewhere. I think his are typically out of .190

My initial thought is to try and find a 150-200 2 stroke and swap the foot on it. Theres no hp restrictions i need to worry with. Would a 150 push the 20 footer? Lots of these motors around here in the deep south.
 
150/105 should push it fine, that is the bare minimum I would get with a 60" bottom and up. That will be a heavy boat so you will need the extra grunt of a 150. Mine is an 03' 1860 Alweld .100 guage, I had it built with 3 transom knee braces and it was and still is a stout boat. I first started with a 115/80 and it would run about 36 with just me in it. Start to add weight and gear and it struggled to get on plane and you had to stay in the throttle. I then jumped to the 250/175 Pro XS and it was an entirely different boat. Topped out at 51 and I could run 35 at about 4000 rpms, it would get about 5 mpg average if I stayed out of the throttle which was the same as the 115 because it had to work harder.

Jet hp is easily figured by multiplying head hp x .7 so a 200 would be 200x0.7=140 so it would be a 200/140 Just in case you didn't know why I was putting 115/80 or 250/175 on here. Jets lose about 30% of the hp in the pump so that is an easy way to figure it.

You can find used pumps, might have to do some searching though. They are specific to model and year ranges, new they run $2000+. If you are going to try and find a used pump make sure the engine you get is a popular one so you have a better chance of finding one.

If I can get them to post I'll have some videos up later on the Outboard Jet link to show you what they are capable of. It will also show you what can happen, it is the day I totaled the boat.
 
Though I doubt I'll ever attempt to go 50 mph, I can understand why the bigger motor makes more sense. With a motor that size on a flat boat how much water do you need to take off?
 
The most important part of a big motor is not going fast, it is having the reserve power for steering when you need it. A jets steering happens with thrust, so if it dies or you shut it off you have no steering. When you have more power most of the time you can give it extra throttle to steer out of bad situations, if you are heading towards logs, rocks, or the bank. Sometimes there is nothing you can do. If you have enough power when it gets extremely shallow, hit the throttle, bump the trim up and most of the time you can make it through (if it is gravel or sandy bottom, rocks are different).

If you takeoff hard you will need about 2 ft of water. If you take off gentle and work at it you can takeoff in 18" or less but it takes a lot of practice and cleaning rocks out of the grates to see what it is capable of. If you get the boat built with pods, they will support the weight better and the rear end won't squat as much on takeoff.

A 150 or 200 will give you enough power to back off while on plane and keep power in reserve also. I always wanted a 250 and the 200-250 Pro XS models all weigh the same, so it was an easy choice for me.

In those videos I posted there is a lot of 2-3" water I ran that day. There were a few spots that went less.
Up until the time I hit the rock I had only bumped the bottom about 3 times, and the grates only picked up 2 rocks all day.
 
This has made it an easy decision to make then. I need at least an 1860 with a 150. Although that 1870 Alweld makes looks pretty great too. Thanks!
 
Looking at Alweld's spec sheet, the 1860 is rated for a 90. How do these dealers manage to sell these boats with 150+ outboards on them?
 
A 150 on an 1860 should push it at about 40 mph at topend speed. I usually run around the 30-35 mph range, good cruising speed and saves lots of fuel.

An 1856 Alweld JC Jet boat is rated for 150.

Around here they don't check hp tags unless you are in hp restricted waters. There are guys that run 250's on 1756 boats. Only thing you have to be concerned about are liabilities and if insurance will cover them.
 
I doubt they would check you here either. The problem comes trying to get a dealer to overpower a hull's rating. I know my closest Weld-Craft dealer won't do it.
 
I think I'm going to go with that 2072 as well. I went to chat with my local guy yesterday and he had this one sitting out in the yard. I was thinking I didn't want a 20 foot boat but it's not really as big as i was thinking. If It's not this one he'll build me one just like it. All 1/8 with heavier wide gunnels, which I really like. They're wide enough to sit on.

 
Jsmoody, have you considered an inboard boat. For the needs you are describing I would highly recommend an inboard v8 boat or a sport jet to seat 6 adults and run 20-30 mile stretches of river.
 
I have thought about it. I don't like the weight issue for one thing. That boat with an inboard v8 would be 1500-1700 lbs before I even stepped in it. If I ever did in fact beach it I don't know how I'd ever move it.
 
Just to give you an idea, I run a kingfisher 1875 extreme shallow with 200 sport jet. I routinely beach the boat on the shoreline to let the kids out to play in the water. I do have a uhmw bottom but I can push the boat back out into the water by myself without a problem. My boat is lighter than the v8 boats but they run most of the same water I do. I occasionally like to run the real shallow stuff cause it's just plain fun. Unless you really plan on pushing the limits in the shallows a 12 degree v8 or sport jet boat would handle the depths that you stated you would like to run. Full windshield and top are nice for those long rides too. I guess my point as far as weight is concerned is that a 2072 Jon with a large outboard is not gonna be any fun to get unstuck if you stick it bad either. You are still gonna need a bunch of friends and maybe a winch to get back into deep enough water. I think that once you learn to read the water, it's just a matter of staying away from the real shallow stuff and knowing the limits of the boat. Only other thing I can add is I would much rather listen to the exhaust note of a v8 for 20-30 miles than a sport jet or outboard.
 
No doubt about the engine noise. I've heard sport jets are loud. Then again, I can't see how much louder they can be than all the 2 stroke outboards on the river. Mine is pretty loud. I've seriously considered sport jets, and am not opposed to it at all. My questions about those are really more about life expectancy vs an outboard. I would really like to have one in a boat. I haven't been able to find much info on what it would cost to get a new one. It makes a lot of sense though to go for an extra 100 hp for the same weight.
 
Different manufacturers go to different lengths to quite them down. Honestly my 200 isn't that bad and the performance is great. As far as life expectancy goes it's like anything else. Take care of it with good maintenance. They took care of the reed issues the earlier ones had. Biggest failure u will hear about is the low pressure fuel pump or lift pump. It's a cheap pump and an easy fix. Most carry a spare so it can be changed on the water. The sport jet boats are fun. I was just thinking v8 because of your need to be hauling 6 adults at times plus some gear I'd imagine. The sport jets can haul that weight but my boat loses a little bit of its sporty feel when weighed down. I guess the best advice I can give is test drive whatever you can and go with what feels best.
 
Unfortunately im in Mississippi and i dont know of anywhere i could test drive a similar boat. If i end up with one im going to take it on as a custom project with my boat builder.
 
That makes it tough if u can't drive a few different boats to see what you like best. Custom builder should be able to point you in the right direction though. If you do end up going the sport jet route, be sure to get a stomp grate for clearing the pump of debris. I don't use mine often but it's real convenient when the intake grate clogs. Only other thing to be aware of with the sport jets is the stock reverse bucket sucks. U can have extensions welded to the bucket or go with an aftermarket bucket that will actually give u reverse. Good luck with it.
 
For that boat and 5-6 people you absolutely need the 250 guaranteed. If you do the inboard maybe not.
 

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