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I find this discussion informative and kinda funny.
I have no experience buying a used boat or selling one for that matter. I bought Shiva, a Contest36s new.
My sense is that some boats have modifications which peculiar to that boat... or have gear which may not be well known. I give some examples.
My batteries for starting the engine require that both the House and the Start bank switches be on. If you try to start the engine with ONLY the Start bank a 15 amp fuse is blown. So someone new may turn on the Start bank and try to fire up the engine and find it doesn't start and likely not know that they blew a fuse.
You don't need the start bank to run the engine... all it does is drive the starter motor.
My AP... Alpha 3000 is not connected to GPS. It works perfectly... but YOU have to dial in the course you want. It also requires that the ram which drives the rudder post be mechanically engaged into a link arm. This is done with a teleflex cable, But to engage the piston needs to be aligned with the link arm. So... I disengage when the helm is centered... and so I engage it at Center Helm. In fact the AP does not need to be ON to do this and sometimes it's better that its off... and not trying to steer. Once engaged the AP will immediately steer toward to set course direction. So... to use the AP.... set the AP course dial to the course the boat is on... refer to compass or instruments. Turn it on. Next engage the ram... once engage use the dial to steer the course you want. Do the reverse to return to manual helm. Turn the AP off... disengage the link arm.
Actually sailing the boat is no different from any other sloop... trim sails and steer.
All my equipment is set up to how I like to sail.... and that may not be how others do. I doubt the average broker or buyer would know how to "work" my engine drive refrigeration.
As far as revving the diesel... I have no problem with that.
I would never let a broker and a buyer take the boat without me. Further I would not want to show the boat to someone who is unfamiliar with Contest.
 

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There is no way I'd sell a boat and not be the one operating it on a sea trial.

Mark
that is not the issue... I believe the question was have a broker and an buyer do a sea trial without the owner on board.
 

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The owner of the boat has the right to insist on being there. The seller has the right to insist they are not. Guess how that works itself out.

Personally, I don’t want the owner there, but as a buyer, I would not likely walk away, if they insisted. I would walk away from the boat, if they became a distraction or were a jerk about it.
As a buyer.... what is the objection to the owner being on board for a sea trial? Is the purpose of the sea trial to get an idea of how the boat sails and motors? Of course when the wind stinks you can't assess how it sails... If seller wants to see how the engine works, the boat steers an so on... what does having the owner there have anything to do with that?
 

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Buyers are there with a critical eye. One that most owners would take offense to. It’s simply uncomfortable for many. If that distraction leaves a buyer feeling they didn’t get to do the focused review they wanted, it’s a negative.
Hang on.... boat is for sale... Buyer visits the boat with a broker... Probably owner is there to answer questions. Why would a seller be offended? He might think... "this buyer doesn't know much... what a jerk..!" Does it matter if he pays the asking price or more? Low offer... seller could be "insulted"... Sorry mate... I don't consider the offer serious... I have things to do... Have a nice day... (then calls buyer's broker if there is one... look don't bring non serious people to waste my time.

By the time they are having a sea trial... an offer has been made,,, maybe even a survey... who cares what the seller and the broker say or think????
 

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My engine has a OEM spec for max RPM... something I never used as something like 2100rpm give me hull speed.. Conditions matter.... and it makes sense that hull speed rpm is not to "red line"
So... what is learned by running engine at full rpm...is that in gear or neutral?
Only use I can see in gear would be in a "panic situation" to avoid a way too close hazard.
 

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Yes, I would be present for a sea trial. For one thing, I can operate my boat more smoothly than any stanger, since I know her systems better. I will make her look better. If you don't want to be involved in a negotiation, don't talk.

And yes, if you refused to let me sail the boat hard, you just told me what I need to know. I'm walking. While I should not be allowed to do anything dangerous during a seatrial, full RPMs and sailing with the rail in the water are normal for a test, and if you think your boat is too fragile for that, then tell me that up front. Otherwise, I'll assume you are a liar.

30 knots is a bit much, but my last sea trail was in 20-25 and reefed. I bought the boat. Certainly anything up to 1 reef is reasonable, unless you believe the boat can't handle that....:sneaky:
I suspect most sea trials are conducted in benign conditions... not challenging ones.

What do you want to learn in a sea trial? Be specific
 

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Be specific? You know, of course, that the list would be long.

  • Will the engine run WOT for at least 15 minutes without overheating? The OP thought this was unfair, but I think this is a TOTALLY FAIR test. I can't imagine not running the engine at WOT for a time. That's why you are there.
Is WOT wide open throttle? My engine temp will rise... I suspect the cooling system can't "keep up" with the additional heat generated. Who runs their engine for 15 minutes WOT? I never have in 36 years.
  • What is the sail shape under a real wind load? Do they point and how is the helm? You can't judge the drive and helm in light conditions. Polyester sails often look good until the wind blows.
  • Does the furler work smoothly in the wind (no, this is not the same as in light conditions)? They can be fine at the dock, but friction from failed bushings and bearings is only revealed under some load. Furling in 10 knots up wind (instead of off the wind like a seaman) is enough.
I think some can assess a furling system is typical conditions. I don't know how you use yours, but I have a Profurl, which I can and DO winch in. and furl in at almost any wind speed.

Then, there are boat-specific details that in theory you could already know, but not all boats are common with reliable reviews:
  • Does she pound? Specific to cats, does the bridge deck pound going to weather?
  • How does she motor into the wind? Many outboad-driven boats will cavitate, others will not.
  • How is the motion? The numbers don't tell you everything.
  • How does she tack (this is an issue with many cats, but all boats to some extent)?
  • Is she dry or wet?
These are somewhat subjective and dependent on conditions...
Motion is subjective... related to LWL, hull form, wind and sea conditions
Relative.. may be important to a racer... critically so.
Relative... my boat is quite dry to sail,. but there is sea spray.. most conditions the boat is dry

But you are not going to learn all these in a one hour sea trial PERIOD. Better yet is to research the boat and ask the owner... assuming you can trust their responses. But is trust important when doing such a transaction?


A sea trial in zero-to-nothing is very nearly a waste of time. I would reschedule, and have.

You can see how boat motors, steers.

No, I'm not suggesting a near gale, but 10-15 knots is a good window. But you don't really get to pick and choose, since these things are scheduled. Might be a little more, and that's when you see how good she is. What I am saying that is some buyers will walk if you require she be babied during trials. We'll smell a rat and run.
10-15 true is ideal...
8-10 is good enough for most "tests"
 

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I am responding, not as a buyer but as a seller of my boat.
As such... I still have the original prop.. so hard to conceive if is not proper design... boat motors at hull speed... and it doesn't need full "WOT" to achieve that.
So I don't know engines and would think no one pushes a motor passed the red line to WOT and I can't imagine the cooling system is designed for those operating temps. I do not that when I pushed the throttle past the normal needed for hull speed temps do creep up a bit. If the gauge stays in the red zone... it is a concern and means blocked/fouled hose or messed up impeller or busted exhaust elbo, I have pushed the throttle all the way for a very brief burst.. so I know it can get there... but don't know what this demonstrates about the motor.

It is EXTREMELY rare to get the rail in the water on my boat.... probably because the high freeboard, In fact it's not even likely to have the ports inside the water... Sure they get splashed. THAT heeled is bad sailing (on my boat)... I sail at 15° and 20° is too much... boat is making too much leeway.
 

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Sure, but the survey is designed to confirm it, not take your word for it.



Which red line are you talking about, rpm, temp, pressure? In any event, the engine should operate within them all at WOT, which is the point of testing it. Not sure why that doesn’t make sense.



It’s but one indicator of the health of the motor and drive train. Simple. Just because you can make hull speed does not mean the engine, transmission and gear are necessarily fine. If any of these had too much back pressure, there may still be sufficient excess HP to get to hull speed, but it would be taking a slow toll on the entire system.
I know I can get the rpms to what I recall is in the Owner's manual and more than I use to cruise. I also know a fouled prop and a bottom add load to the engine.

I don't understand engines and would like to know what a WOT would show? I googled WOT and it's about matching a prop to the engine.

"“An engine that does not reach the rated RPM at wide-open-throttle is an “over-propped” condition, resulting in “lugging.” This high-torque operation puts a tremendous load on the pistons, crankshaft, and bearings. The engine runs much hotter and may overheat from having over-advanced spark timing for the reduced amount of fuel entering the engine. The mechanical strain on an over-propped marine engine is like starting an automobile in third gear from a dead stop at the bottom of a hill. This severe strain can lead to detonation, piston seizure, and engine damage.

On the other hand, an engine that revs past the recommended RPM will have higher than normal wear and can also be damaged by fatigued parts breaking and passing through the engine.

This is why it is so critical to be sure your engine is propped correctly for your boat/engine combination and the type of boating you want to do.”

I would like to add that what your engine does at WOT tells us what it will do at other throttle locations. In other words, if you are lugging at the top end, you will be lugging in the middle and at the low end."
 

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I'm never surprised in the hundreds of sea trials i've done with what fails under moderate stress that should be within the capabilities of the vessel. I've seen shaft flanges disintegrate with a short burst of full throttle (that one I warned them about). I've seen motor mounts that looked fine at the dock but showed broken bolts when the engine moved 1" off the beds under heavy loads in reverse. I've seen exhaust manifolds leaking profusely at high RPM under load which showed no leaks at hull speed RPM. I've seen rudder stock knees move 1/2" with a hard turn of the rudder. I've seen autopilots that had conniptions if you used the jog at hull speed.

If the owner will not permit a little stress what is he afraid of ?
I was unaware of the WOT "test". It hardly seems like a "little stress".... but I don't know much about engines. I do know that my MD17D which is quite old has a recommended OEM "RPM operating range.". As I noted in an earlier post that I never have had a need to even run at the high end of this range because I can achieve hull speed as lower RPMs.
Perhaps there are times when a burst of full throttle may be called for. I'd like to hear of some examples. But surely not for 15 minutes WOT.
My naive sense of this matter.... is that if the mfg gives a recommend max operating RPM, the user should observe it.

WOT seems to be excessive stress. Who knows, it may cause some damage.
 

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Thanks for the comments.... they are somewhat helpful.
I don't know what WOT is on my engine. I do know that 2100 RPM is what is needed to reach hull speed. I have pushed the RPMs to high 2000s at times for very brief periods... perhaps needing to give a burst of speed for some reason. The engine did not suffer. Actually I am not sure that the throttle can add more fuel... it seems to be limited by the morse cable installation travel. As I said mine may be limited to the high 2000's RPM.

What is WOT technically?
 

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Apparently WOT test means something.... but it's not clear to me. Apparently some buyers believe this test will tell them something. And for sure one would hope that the engine can run at high revs without "failing".

My research reveals 3 goals for a WOT test
1. confirm that the prop's pitch etc is matched to the engine
I am not sure how many minutes WOT is needed to check the prop. But a "bad prop" limits WOT... which it a prop test!​
2. confirm that the engine's cooling system works (at those RPMs) and doesn't overheat
This apparently can show a sub par cooling system even though at normal RPMs the engine does not over heat. Good to know I suppose​
3. determine at what RPM the engine's governor limit is.
Why this is important is not clear... I suppose to prevent the engine from being able to run too fast when bad stuff happens. This is not a time test. Push the throttle and note max RPM. done​
My sense is that a prop design is calculated. Whatever prop is fitted.... can't measurements determine if it correct? (in my case... I have the OEM prop fixed 2 blade. I presume it is proper and the buyer who doesn't want to believe me.... can call the factory and do his own prop research. If it is a proper design it will not inhibit a WOT RPM reduction.

So cooling is likely the key issue... and reduced cooling could have multiple causes... including blocked intakes, hoses, elbow, missing impeller blades and so forth.
 

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As mentioned by someone earlier, running loaded at WOT can also show engine mount issues and cooling system leaks, among other things.

#3 isn't really a thing, since governed WOT is known for most engines.

Mark
I suppose #3 is to determine if the engine is properly governed.
Bad mounts would be revealed.
 

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WOT is whatever the engine is governed to. On the MD17D, it is 3000rpm.

Mark
The Volvo-Penta MD17D model was made from 1981 to 1984 and had a slight increase in performance. This motor achieves 36 horsepower at 3,000rpm and is capable of 3,350rpm. MD17D has a compression ratio of 17.5-to-1 and features a displacement of 102.51 cubic inches. The heavy duty MD17D heavy duty has a max of 2,900rpm.
 

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I don't think running it up to WOT, while tied to a dock, is the same as being underway. The momentum of the boat will reduce load on the prop a little. The prop is pitched for being underway. Kinda of like starting to peddle in a high gear, after a few turns it's a bit easier. Not terribly surprising that a cleat let go.
This is correct and ALSO a test of the prop "design"... pitch etc. WOT at idle would test the cooling, and mounts for example... that the governor is properly set.

This makes me think... about motoring. Is it important to determine in a sea trial what speeds the boat achieves at various RPMS... ie "cruising speed" ... hull speed... idle speed (slow as possible)... in reverse?
 
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