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possible Dyno Jet Build?

Posted: Mon Mar 29, 2021 3:54 pm
by electric tug
Hi all...
Im looking at two designs. a Jet Setter(see my other post on here). Or a Dyno Jet.

I know the DJ will be the cheaper option. but the kicker is the material for me.
I just dont like wood. I need a strong boat to run off rocks since I live on the shore of lake Huron, There are shoals, and rocks everywhere.

If Im going to invest time and money I want a light strong boat able to be fast yet handle hitting a rock or shoal and not holing it or totaling the bottom.

so problem # 1. (I know I just cant make it simple can i?) :?

I thought about having another go at an alternative material such as Nida core, or Corecell/Dyvincell.

For those wondering back in 2016 I tried doing it in Nida core, but I was limited in my space, to build, and had to put the project on hold.
One issue was that Nida core uses 4 x 7 sheets which messes up the use of patterns. Nothing more room couldn't overcome, by joining two panels of Ni Co then using the patterns. my worry is- will the Nida core be able to fold in the same or similar way as plywood using the stitching method?
i.e. can it be closed up like S & G without tearing the PP in the process? same would questioned about Corecell etc.
the other issue with these materials is HOW do you mount things to the hull? Core won't take a screw. so how do you do, engine mounts, fittings etc using core?

#2

I also wondering about fully coring the plywood hull?

One way would be to increase the bottom to 3/8" instead of the 1/4" called for.

I could just add two layers of 1708 biax on both sides of the hull. This would make it heavier. but less than steel or AL.
I am wondering tho, if it would be enough. would the ply core shatter if I hit a rock (whereas Nida core and Corecell would likely not).

if anyone who has built one of these can tell me how strong the boat was without using the extra frp? Have you hit any rocks? and if so how did it turn out?

#3

I thought about Aluminum and even light gauge steel.

I am not set up for working in AL. so thats not an option. to use Al, I would need to retool, and the tools costs are more than the boat costs for me to do AL. for a one-off. So it doesnt make sense to me.

but I could use 16 gauge or even 14 gauge steel on the bottom and lighter steel for the topside and deck. sure it would weigh about 100+ lbs more. but it would be solid and likely not hole. altho It might deform enough to make a repair difficult. It would get me home.

#4
how much room for an engine?
I want a large engine. like really big! I have even thought of a small car engine like a suburu, or even a 180 hp mercruiser.
so i am wondering if the displacement could hold a larger engine, and is there enough room for a larger engine?
I have seen v8's in jet skis so I know a small 4 or 6 cyl could possibly work.

I have seen a lot of pics, but it just seems to hard to tell just how much room there is in the engine compartment?

https://www.youtube.com/watch?v=BK2ojOcleKw&t=1s

This shows the engine room, but I would use bigger engine to really eek out some performance from it.
anyone who has built this, could you tell me your thoughts on engine size and capabilities from this hull?

ok, thanks Ill leave it there...
Doug

Re: possible Dyno Jet Build?

Posted: Tue Mar 30, 2021 5:38 am
by Basothobryn
I received my plans for the nimrod last week, I plan on powering it with a 1000cc or more 3 cylinder engine powering a jet pump. Current plan is to isolate 4 or 5 sections of the boat and lay down fibreglass and divincel (sic) in those sections on top of the plywood. If my nephews or I jag a rock we still have a chance of staying afloat. I live in Australia where the nanny police work overtime, so it is partly due to hopefully getting some form of registration that the plan is heading that way. I still want the wood look in the cabin area so I won't be laying it down in the mid section.

Re: possible Dyno Jet Build?

Posted: Tue Mar 30, 2021 7:35 am
by electric tug
hey Basothobryn.

Good luck on your build. I actually have never seen that boat but, thats a beautiful design! That might work for
me too, since I was thinking 14 ft would be ideal. This would give me room for a larger engine, but still small enough to use a 6 inch pump.
Thanks a lot for bringing that design to my attention, it would make an exceptional jet boat hull it seems. Im going to research it further.
good all around boat!

Re: possible Dyno Jet Build?

Posted: Thu Apr 01, 2021 12:00 am
by Basothobryn
Cheer E T. Would be great to have another on the go. Other mods I plan are to stretch it the 10% permissible. move the cockpit back a little for a longer foredeck. And I started making the seats last week. Afold down bench seat in the middle for 2 (small sized peoples, and have 2 fold down single seats in the rear facing inwards. When I sketched it up it looked like a warrior wearing a mask from the sky view with the boat pointing down, And that sealed it. Will post some pictures but if you got a pile of recycled timber and throw it onto a strong back you would have an idea on how it looks at the moment. Keep me informed on your plan please. Have a nice day bb

Re: possible Dyno Jet Build?

Posted: Sun Apr 18, 2021 6:00 am
by cepjr
Electric tug'
Not sure how fast you want your dynojet go,I put a triple in mine 80hp and its far from slow!!!
The engine compartment fills up quickly. I moved the seat forward 2" and kicked the jet out the back 11". I'm still in the break in process for my new motor but I've got 42 mph at 5200 rpm one the operating range is to 6300 by my math it should make top speed at or just north of 50mph!!!
Its still only an 11' boat!!!!good luck with your build which ever way you decide to go!!