Can one do a sea trial on a river?

[Montemar]

Happy New Year folks.
I am considering buying a boat moored on a river which has a pair of 200hp VP engines. I can get an engine specialist to look at them and have the oil analysed but how can they be sea trialled when there is a 5 knot speed limit? A sea trial sounds like a complete necessity but is there an alternative method when a considerable distance away?
Thanks in advance for your help.

 

[Trundlebug]

It depends on where you're talking about exactly.

We have the same problem at Farndon on the Trent, but there is an unwritten acknowledgement that powerful sea boats need to stretch their legs properly to be tested, so the marina staff take the boat to a suitable stretch on the river where there is minimal inconvenience and give it a short blast.
You're not the first in this situation, and you won't be the last. Discuss with the broker / marina selling the boat and they should satisfy your concerns.

I might add - we have waterskiing stretches on the Trent, which are handy for high speed sprints although the section near Staythorpe power station is wider and tends to be the preferred spot. Although not by (miserable) anglers. But they're never happy anyway.

 

[jrudge]

Which river? I bought a 2 xs 300 hp boat on the Thames, and there was a place near Penton Hook where you could give it a go!

Now I was green then ( but equally the thing was 3 years old with 200 hrs on it) and the snag is it is not really about giving it a squirt, but also checking it does not over heat etc at WOT, tracks reasonably straight, no vibrations and so on.

I would think that most buyers are going to have a similar view to you, so it is not really unreasonable for the owner to run it down stream for the purpose of a trail.

Knowing what I know now, and not what little I knew then, I would require the vessel to be given a decent run before buying it.

 

[Greg2]

There are sections on the Broads where speed trials are permitted by bona fida brokers. Essential to get a proper trial IMHO

 

[PlanB]

When we bought our 435 from Penton Hook we had two separate day long sea trials taking her down to the unrestricted stretch of the estuary.

 

[volvopaul]

A short blast on a river like the Trent it Fossdyke which are two inland rivers which sport boat dealers, I carry out engine surveys at both, I will be honest in the fact that both areas have legal speed limits which cannot be broken, every time this is carried out by the dealers a chance is taken on getting caught or reported to the authorities. The only fact it can prove is acceleration performance from a stand still, engine acceleration balance and a smoke test. To obtain a true trial whereby maximum temperature can be checked the engines need to be run flat out for more than 10 minutes at least, some cooling systems will run up to thermostat opening temp, stay stable then overheat even after 10 mins running at flat out position. A river is no place to rest correctly, the last one I did was at 31 knots in an F42/5 with barely a foot of water under the props and 2 metres either side the boats hull, very dangerous should the boat go offline. If your buying and you want to test make an agreement in the deal that a further test is carried out when the boats delivered to sea and any further faults carried out at cost by the seller, it's not uncommon to ask for this when buying a sea boat inland.

 

[CX54WEK]

The brokers where we moor have trade plates and are allowed a set number of high speed runs.

As Volvo Paul says though its far from ideal as the ditch is shallow and not very wide.

 

[Switch]

I tested the first boat I bought on a river (Medway). It was a 37ft planning mobo with twin KAD300's. We were able to do high speed runs on the river so the engines and systems could all be checked, however, the river trial gave no indication of how the boat would feel at sea or in any kind of chop. I went ahead with the purchase (perhaps naively - it was my first boat) and subsequently found the boat slammed rather more than I expected at sea (despite it being an off shore cruiser). Of course all planning boats will slam depending on the conditions and how they are driven - but the boat I purchased would slam even in quite benign conditions I don't regret the purchase although I did sell the boat after a year to go bigger - but my point is that had I had a proper sea trial then I would have know about the boats tendency to slam and that would have played a part in my decision making progress.

 

[ontheplane]

No.........

.......it would be a river-trial!

 

[scej]

As people are saying on here a river is no place to seatrial that type of boat, i would suggest to the broker that you take the boat into the estuary and run it for a decent amount of time to get up to temps and full load.

Now as for having the oil analysed, unless you have a history of oil samples or at least the last one (i.e. from the last service) then you won't learn anything about the engine because it will only give you a base reading of metals etc in the oil now, not a history. If your surveyor is insistent on oil samples make sure when they poke the tube down the dipstick tube only as far as the dipstick will go. the reason for this is there will be some sludge in the bottom of the oil pan which is not what you want for your sample. It should be noted that engineers change the oil by vacuum pumping it through the dipstick tube and they will never remove all of the oil so there will have been a residue since it was new and if the oil samples are taken from randomly shoving a tube down the dipstick you will not be taking the oil from the same spot on the engines to get a comparison.

I suspect i will now take some abuse from various people here defending oil sampling without previous data. This is my view having run a decent size boat where we monitored oil samples at each service not just a random sample on purchase.

Happy New Year folks.
I am considering buying a boat moored on a river which has a pair of 200hp VP engines. I can get an engine specialist to look at them and have the oil analysed but how can they be sea trialled when there is a 5 knot speed limit? A sea trial sounds like a complete necessity but is there an alternative method when a considerable distance away?
Thanks in advance for your help.

 

[Montemar]

Many thanks to all for their replies.
I have thought of a ( probably barmy ) option: reversing up the river flat out! Would the stern gear and/or gearbox cope? I reckon it would give the engines a good workout at greatly reduced speed.
What does the panel think?

 

[Seastoke]

Many thanks to all for their replies.
I have thought of a ( probably barmy ) option: reversing up the river flat out! Would the stern gear and/or gearbox cope? I reckon it would give the engines a good workout at greatly reduced speed.
What does the panel think?

what if gearboxes are nacked going forward ,

 

[rafiki_]

Many thanks to all for their replies.
I have thought of a ( probably barmy ) option: reversing up the river flat out! Would the stern gear and/or gearbox cope? I reckon it would give the engines a good workout at greatly reduced speed.
What does the panel think?

They are not auto gearboxes, the boat will go nearly as fast in reverse, so I hope there are no others on the river!

 

[benjenbav]

I think the answer to the original question is:

"Once"

 

[Greg2]

When I trialled our current boat I had planned to take her to sea but it blew a hooley so we had to stay on Breydon Water. To make sure that I gave the engines a good workout I ran each engine at full chat with the other in neutral for several minutes each. This gave them a good workout and reassured me that overheating issues etc were unlikely.

 

[Momac]

My surveyor did exactly as Greg2 describes.
Plus a run at almost full on both. It proved, as far as reasonably possible, the boat and engines were performing okay.
Since then I have added 60 engine hours and not aware of any engine issues.

.

 

[Montemar]

Many thanks for all your replies.
Firmly mooring the boat then running one engine up at a time seems a good option. A quick blast should also reveal any balance problems and give a good dea of acceleration. I reckon that should do it.