Riding on a tuning fork !

BillD

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Yesterday I took a sea trial on a nice working lobster layout DE.

Beautiful boat.

Solid glass hull, composite top. Open starboard side. ALL plywood/2X4 wood frame construction.

The engine is hard mounted to the stringers, no muffler, no engine insulation, jack shaft forward, two big pumps off the shaft.

The vibration throughout the boat was very very annoying. :(

Bottom line for me...."Scratch a hard mounted, non insulated, no muffler, plywood construction DE off my list of choices."

FWIW,

Bill D
 

WoundUpMarine

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traditions

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Not all hard mounted engines have this problem.Most likely it was the way this boat was.I have noticed on some boats that have 2 x 4,s that run from the stringer next the engine mount to the deck transfer some vibration to the deck.If the thing is in alignment and the wheel isn't stove up there should be very little vibration.
 

nick4634

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My guess is that the vibration came from those pumps on the forward shaft. My boat is built the same as that one, solid glass hull, stick built house, hard mounted engine, no muffler, wood deck and it doesn't vibrate except at 1500 1750 and 2500 rpm. my pumps for the hauler, steering and wash down are on ptos off the engeine
 

pugsley

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i have a plywood boat, smooth as silk, the hydraulics are usually on universal joints, i would say alignment, or wheel.....or both
 

Powderpro

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BillD- The only engine you can hard mount is a Cummins, because they don't vibrate... all the other brands vibrate like crazy :D.

I'm telling you, get a 30' Calvin Beal or Flowers, raise the sheer 2", raise the house 4"-5", install a 6.7 Cummins or Iveco (preferably the 570hp Iveco), and you will have the baddest DE in your size range. Quit taking rides on other boats and getting building on yours!!:D
 

BillD

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25 Terry Jason with Cummins 370 power
Early in the game? You've been talkin out your ass for years about building a de boat! :eek::eek::D shit or get off the pot man!

I may have a decision soon, maybe by the end of this boating season !

If not the end of this season maybe over the winter?

No rush really.

Hell I'm pain free, up and around under my own power and can take care of my toileting and cleanup by myself.

Do I really "need anything more" ;)
 

eyschulman

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New JD 6068 ply boat hard mount 000% vibration.
 

DBM

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BillD

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25 Terry Jason with Cummins 370 power
New JD 6068 ply boat hard mount 000% vibration.

Our cummins is hardmounted to the stringers on big aluminum plates and there is very little vibration. all of the construction is composite however, no wood in buildup. extremely light and strong.

DBM

In fairness to the boat I rode...she IS a working lobster boat.
My goal was to note gph fuel burn @ 18-23 knots and assess the "softness or hardness" of the ride.

I got all the data I was looking for.

I did notice the the "tuning fork aspect" (for lack of a better term) of this particular boat.

Again, zero insulation, all wood framing and decking, no muffler.

No biggee really.

Any boat I have built or build ourselves will be soft mounted, composite and mufflered.
 

riskybusiness

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BillD- The only engine you can hard mount is a Cummins, because they don't vibrate... all the other brands vibrate like crazy :D.

I'm telling you, get a 30' Calvin Beal or Flowers, raise the sheer 2", raise the house 4"-5", install a 6.7 Cummins or Iveco (preferably the 570hp Iveco), and you will have the baddest DE in your size range. Quit taking rides on other boats and getting building on yours!!:D


i dunno if i agree with you on the only hardmounting cummins....most cats were hardmounted....my 3126 is hardmounted and properly aligned and there is no vibration at all....yes the newer cummins are alot quieter than anything else on the market but there is nothing wrong with a properly mounted hard mount engine as long as it is properly secured and aligned...its just a matter of spending the time to get it dead nuts on....which alot of people dont because you have to lift the engine every time to get shims under it......
 

BillD

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25 Terry Jason with Cummins 370 power
i dunno if i agree with you on the only hardmounting cummins....most cats were hardmounted....my 3126 is hardmounted and properly aligned and there is no vibration at all....yes the newer cummins are alot quieter than anything else on the market but there is nothing wrong with a properly mounted hard mount engine as long as it is properly secured and aligned...its just a matter of spending the time to get it dead nuts on....which alot of people dont because you have to lift the engine every time to get shims under it......

Risky,

Powderpro's comment about the Cummins being "vibration free" was a "stab @ me ! ;)
 

F/V First Team

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We've been known to hook a Sisu up to a water tank and run it during shows. Nothing fancy to sit it on, just the shipping crate. So smooth we can put a 1/4-20 bolt on its head and rev the engine up to maximum rpm. Screw just sits there.

Now that is smooth - and vibration free apparently.
 
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