Page 1 of 1

Heavy boat

Posted: Thu Oct 25, 2012 2:38 am
by Counterfitter
Did a sea trial on a 1989 12 meter express with Detroit 671 's and could not get her to go over 15 knots at 2000 rpm. ( I'm reading the boat will cruise at 25 knots at 1800 ) hauled the boat for hull survey and she came in at 32000 lbs on the travel lift ( I think the weight of this boat should be around 20000) I know I am dealing with a cored hull boat and worried that hull can be soaked . Would this be the extra weight ?

Posted: Thu Oct 25, 2012 5:08 am
by Allen Sr
This should be in the forum section not the runabout owners group. The Moderator should be along soon to move it. Survey should of shown if the core was soaked or not. Sounds like it is.

Posted: Thu Oct 25, 2012 6:58 am
by prowlersfish
Travel lift scales are not that accurate I would think the boat would be over 20000 lbs (a F36 dry is 16000 ant the 12 meter is a lot more boat) Many of the 12 meters are listed around that weight (18-20,000) with gas . the 671 engines are 2850 lbs each . so that would add a lot of weight to the boat . Those engines should turn 2500 rpm at wide open . how clean was the running gear and bottom ? That can be a big factor
in how it runs . see what the surveyor says about the coring. ( if cored)

Posted: Thu Oct 25, 2012 9:29 am
by BarryL
For a frame of reference,

I bought a 1990 10 Meter mid cabin last spring. survey showed no moisture other than a small amount near a stanchion on the forward deck. The travel lift showed the boat to be just over 18,000 with 1/2 tank (120 gallons) with gas 454 big blocks.

So what are we to believe? Trojan specs? or aging travel lift scales. When I had the boat transported via land we didn't pass any scales so I cant verify the travel lift numbers.

If survey shows little or no moisture intrusion and you can get your cruise speed verified and you are happy with it buy it and enjoy it.

Barry

Posted: Thu Oct 25, 2012 9:43 am
by Jerry
Like Paul stated, you can not go off the gauges on a travel lift. I know my 12Meter aft cabin showed 34.5K and it is not anywhere near that.
As long as the running gear and bottom were clean, I would check the no load max rpm as it could be a governor issue. Were both engines at the same rpm?
Also check the wheels as you could be over-propped. That is early death for a diesel.
Do the engines have Air Seps on them? They could be dirty and that would happen.
Any black smoke at all? Are the air doors open? Although I don't think it would hit 2k if they were tripped.
I would also check the fuel filters. All four of them as if they are getting plugged you will not get max rpm. Do the filters have vacuum gauges on them? If so, what is the reading? Is there any water in the seperators?
I also came across a 671 powered boat that had the injector height set incorrectly that could not get on top of the water. These 671's use two different injector height settings.
You really need to find out more information if possible.... Like when was the last time the boat did hit max rpm and what changes have been made since.

When I purchased my boat and brought it home it was as lite as it was ever going to be and I hit 30.2 MPH on GPS at 2500 rpm. My engines are the 671 TI'S.
If I can be of any help, just ask.

Posted: Thu Oct 25, 2012 2:23 pm
by todd brinkerhoff
++1

I agree. The 12M, although heavy, should probably be in the mid to upper 20s with a normal load. Like already stated, make sure engine is capable of turning the full recommended wot + i think 200 or 300. If it doesn't and both are turning the same wot its probably over propped. If they're different, the engines need to be checked
You're definitely lighter than the 12m convertible. Also, if the bottom is not clean and smooth, it does make an incredible impact on speefd. If it is really at that weight, you probably have a water incursion issue

Posted: Thu Oct 25, 2012 4:22 pm
by lawyerdave71
I wish I had this problem!!!

Anyhow did your surveyor use a mositure meter throughout the exterior and interior of the hull?

Posted: Thu Oct 25, 2012 7:06 pm
by summer storm
Factory data I have collected for the book.

12 Meter Convertible 1986–92 19,000 lbs
12 Meter Express 1989–92 18,000 lbs
12 Meter Motor Yacht 1987–92 19,000 lbs

Posted: Fri Oct 26, 2012 5:08 pm
by BlueBelle
For what its worth, my 11M Convertible w/ 671's cruises at 19kts @ 1800 rpm. My last haul showed 30,000 lbs on the lift scales. I believe the scales were inaccurate.

Posted: Fri Oct 26, 2012 6:15 pm
by Big D
prowlersfish wrote:Travel lift scales are not that accurate....
+1
Unless they have been calibrated recently (usually not), I wouldn't base any decissions on those numbers.

Posted: Sun Oct 28, 2012 7:14 am
by rossjo
BlueBelle wrote:For what its worth, my 11M Convertible w/ 671's cruises at 19kts @ 1800 rpm. My last haul showed 30,000 lbs on the lift scales. I believe the scales were inaccurate.
Pretty boat Blue Belle - your repaint?

Posted: Wed Oct 31, 2012 3:25 pm
by BlueBelle
rossjo wrote:
BlueBelle wrote:For what its worth, my 11M Convertible w/ 671's cruises at 19kts @ 1800 rpm. My last haul showed 30,000 lbs on the lift scales. I believe the scales were inaccurate.
Pretty boat Blue Belle - your repaint?
Repainted 5 years ago with Awlgrip. The paint has held up very well. This pic was taken during my last haul, 11 months ago.

Image

Posted: Wed Oct 31, 2012 4:34 pm
by hmc
NOTHING LIKE GOOD MARINE PAINT ! TAKE A LICK'N