jet drive outboard/jack plate
Reply    
    
Previous Page    Page
select
of 1    Next Page
Posted on Wednesday May 4, 2011 at 10:34 PM  
wondering if anyone has much experience with jet drive outboards. just ordered a 50 hp evinrude e-tec with jet drive lower for running shallow water in the red and washita river. having custom boat built; 1752 flat bottom tunnel hull. should I put 27" transom on boat or slightly shorter and put a jack plate on it to allow for some adjustment. the company i ordered the motor from says this motor should be run on a 27 in order to get the intake flush with bottom of boat. this motor is going to be heavy (260 lbs) and I worry about the set back associated with jack plates (causing boat to sit deep in water in back end).
Posted on Wednesday May 4, 2011 at 11:11 PM  
Get your builder to put some float boxes on the stern of the boat.
Steve Carroll Hybrid/Striper Guide Skiatook Lake Fishing Guides, Lowrance Pro Staff, Wave Spin Reels Pro Staff, Yeti Pro Staff, Costa Del Mar Pro Staff, Mercury/Motor Guide Pro Team.





Posted on Wednesday May 4, 2011 at 11:17 PM  
thanks for replying Steve. thought about that but some have discouraged it saying that it adds a lot of drag and greatly decreased speed. Do you think it would affect the speed that much or do you think trim tabs would help?
Posted on Wednesday May 4, 2011 at 11:29 PM  
I'm no expert, but these are very popular in Texas along the coast. Lots of skinny water. Most of these guys don't use jet drives on the tunnel hull boats. They opt for jackplates and conventional outboards on the tunnel hull boats. Lots of boats for sale like you're building on this website.

http://2coolfishing.com/ttmbforum/showthread.php?t=341530
Steve Carroll Hybrid/Striper Guide Skiatook Lake Fishing Guides, Lowrance Pro Staff, Wave Spin Reels Pro Staff, Yeti Pro Staff, Costa Del Mar Pro Staff, Mercury/Motor Guide Pro Team.





Posted on Thursday May 5, 2011 at 12:31 AM  
Yeah the sponsoons add drag and slow the boat a small amount but add a ton of floatations and allow a standard outboard to run jus about as shallow as a jet drive and the thing with OB jets is that 50 will produce about as much speed as a 25hp outboard wouldve with a prop. Sponsoons + jack plate is the absolute most efficient shallow water setup you can get unless your running over rock shoals and trees ect then a inboard jet is king of the hill OB jets are near worthless
Resident forum pirate... YARRR
Posted on Thursday May 5, 2011 at 7:37 AM  
A friend of mine just purchased a 50hp Honda outboard jet which pushes 35hp on his grizzly 1860. I don't think there's enough power to put it on plane but who knows, he may not have it tuned in just right.

Posted on Thursday May 5, 2011 at 8:50 AM  
I HATE to throw COLD water on your project, but you are going to be very DISAPPOINTED with the performance of the rig you are building -- I have been running OB and inboard jets for twenty some odd years

First off lets look at your motor -- in ALL jets EVERYTHING you do is with POWER to get on plane -- ALL OB jets are DERATED 30% at the jet output, all inline jets are derated 15% -- so if you intend to use a 50HP ETEC head your actual HP at the jet Pump will only be 35HP -- I expect that hull will weigh in around 500#, add your weight plus gear and motor for another 400#, if you intend to carry a buddy another 200# -- so you will be pushing ` 1200# loaded -- thats asking A LOT from 35 ponies == you will be LONG to get on plane and you will find you have to STAY in the throttle to get any performance at all -- this will shorten your motor life

If you intend to fish out of it alone mostly you still will just barely operate in the motors best RPM curve -

You will really need at least 60 HP output at the pump - that means at least 80HP at the head.


AS far as transom height, and tunnel -- ideally the tunnel itself should be NO LONGER than 18" and no deeper than two inches -- no wider than the Jet foot itself, your transom should allow for set up motor height to where the Foot rides IN the tunnel - this will be slightly ABOVE the hull level INSIDE the tunnel --

Sponsons normally are needed if the boat is NOT properly set up as a jet boat -- all jets when sitting IN the water, with gear and driver should sit LEVEL, not nose down and not transom down

Jet boat performance is little understood in this part of the country

Look at Allweld jet tunnel hulls
http://www.alweld.com/basic_jet_boat.html

Go to Rockproofboats.com talk to the owner of the company
Look at Snyder boats.com

These guys are the pros in this part of the country
http://www.jetdoctor.net

Here is a good example of a jet OB properly set up


You will thank me later for saving you some serious disappointment

DO your homework

Water Jet propulsion works on POWER, you are throwing water OUT not AGAINST anything which provides forward momentum -- - the faster you can accelerate the water stream, the more thrust you have, water does not compress you have to throw it HARD for thrust.
Those who would give up constitutional freedoms to elected officials in exchange for a false sense of security, deserve neither freedom or security.
Posted on Friday May 6, 2011 at 10:26 AM  
One other thing I failed to mention on your hull -- a good jet sled needs to have the bottom plate extend 3-4" out beyond the transom bottom -- or I can guarantee you the first time you clock a rock (and you will) you will be peeling the transom away and putting a hole in it --
Those who would give up constitutional freedoms to elected officials in exchange for a false sense of security, deserve neither freedom or security.
Posted on Friday May 6, 2011 at 10:34 AM  
thanks for the imput guys, I will take all of your suggestions into consideration.
Posted on Tuesday May 10, 2011 at 9:08 PM  
I'm not sure you'll need quite 60 horses at the pump. I have a 1754 grizzly with a 60 horse merc and I can get on plane at 3300 RPM with 4 people, (800 lb) 55 gallons of water, (440 lb) and batteries, trolling motor, etc. Having said that, I don't think there's a chance my boat would get on plane with a 50 HP with a jet Lower Unit. Also, I don't have much experience with jets and don't know about the ability to trim and adjust the "vector" of the thrust which helps get on plane. So maybe you will need 60 horse at the pump. I realize I just contradicted myself and that didn't help at all, but that's my $.02
Posted on Wednesday Jun 1, 2011 at 8:21 PM  
I ran a 55 horse jet (that is down rated with the conversion) on a good size jonboat I loved it and actually ran it up the Washita a bit as well as a lot of other places on Texoma. I sold it a couple years ago now and wished I still had it, but can't keep all the toys I want I guess... I would love an inboard set up jet, but my 18.5' Weldbuilt Jon ran pretty good. It was a lighter boat thought. Once on plane it would run shallow shallow, but scary when you are running in 4" of water and know you can't stop!!! LOL Once you commit you'd better JUST DO IT!!! LOL I think Tony is a bit crazier than I am from what I've heard. I haven't been with him on a river ride! LOL


`·.¸¸.·´¯`·.¸.·´¯`·...¸ )}<((((((º>
Reply    
    
Previous Page    Page
select
of 1    Next Page