Running under load - on the pontoon

[h4nym]

Folks

Doesn't look like I'm gonna get out to sea this year, so am pondering what do do to run the engines under load for a while while on the pontoon - she's been pottering up and down the river at tickover for most of the season.

Is this sensible? Will the load place a potentially unbearable strain on the cleat(s)/hull/warps etc? Or is this standard practice in this situation?

Also - how long should I run them for to give 'em a decent blow out? And at what revs? Volvo TAMD40B's, by the way, 165HP

H

<hr width=100% size=1>Life balance?

 

[Strathglass]

Standard practice for a hire yard I used to work for. Stinkies and raggies. A quarter hour at about half revs in the hour just before the punters came did wonders to overcome the lack of starting ability. It was the only way to generate enough energy to heat the calorifiers. The engines would not warm up off load.
But make sure your deck cleats, those on the jetty and the mooring ropes are up to it.

Iain

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[lanason]

It's normal for most people to move to a different marina - not to move the marina further downstream !!!

Similar problem to you round here - so the trailer helps get me to the sea for a blast (when the V*l*o allows).

<hr width=100% size=1>Adrian
<A target="_blank" HREF=http://www.arweb.co.uk/argallery/kelisha>More Pics of Kelisha</A> /forums/images/icons/smile.gif

 

[Moose]

I tried this and manged to move the Fuel Pontoon about 6 feet!!/forums/images/icons/smile.gif
I also have a nice "cave" in the bank behind me.
740hp makes some quite impressive prop wash

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El Alce

 

[lanason]

Tell me next time and I moor up stern to stern and we can hope the washes cancel each other out. /forums/images/icons/crazy.gif

<hr width=100% size=1>Adrian
<A target="_blank" HREF=http://www.arweb.co.uk/argallery/kelisha>More Pics of Kelisha</A> /forums/images/icons/smile.gif

 

[MainlySteam]

You will likely find, assuming cleats and marina are up to it, that beyond some rpm determined by how your boat is propped you will over load the engine. I know you are not a fishing trawler (!!!), but for the sake of example a vessel such as a trawler propped for slow speed towing will be more capable of low speed loads than one that is not. Overloading kills commercially rated engines and I assume more so pleasure rated ones (trawlers are normally propped for towing, not for getting to the fishing ground).

I am not sure of the ramifications for a planing vessel which is propped to at least get it over the hump onto plane, but clearly any overload in doing that is normally of short duration (although one does see planing boats being driven around on the hump) - so I am just suggesting this may be something to watch out for when you try towing the marina around.

My own boat is a sailly one (although I have professional interest in MoBo's) and I can overload the engine of that by towing the marina. On one occasion I was asked to do a very quick inspection of a 125 foot super yacht's condition and did not have time for a sea trial - had the crew run the engine up against the marina berth but did not dare even engage any drive other than a very slight bit of pitch on the prop.

John

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[DepSol]

Someone did it in Beaucette once nd ripped away the pontoon. Same happenened in Lezardrieux last night (glad I stuck mine on the outer mooring) and caused havoc.

Aprt from that I dont think its that great for the motor!

<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>

 

[andrewbarker]

Do one ahead, one astern. Cancels out pontoon tearing noise misery! Also watch out for overload - suggest 1500rpm max.

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[tcm]

i have seen this done, I have always seen it done stern-to, though, on concrete pontton, gentle lifting of revs won't put too much power through cleats , and use middle as well as stern cleats. However, as others say, not terribly effective, seems to do more marina-stirring than give the engines much of a blowout. Can you not get to the sea and give them a thrashing?

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[hlb]

My mechanic does it all the time, when testing engines. Frightens me to death. They just wam it in gear about half throttle. Soon gets it warmed up though!!

<hr width=100% size=1> <font color=blue>No one can force me to come here.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[milltech]

I used to do it to spring 65 tons off, mostly it was OK but the marina manager at St. Vaast had a baby about it, didn't think his cleats were up to it.

<hr width=100% size=1>John
<A target="_blank" HREF=http://www.allgadgets.co.uk>http://www.allgadgets.co.uk</A>

 

[Moose]

I saw a big torpedo boat do it at Gunwharf a few months ago, they ran there monster engines at half power for a good 20mins to "stabilise" them before heading of to the Solent, the wash was distrurbing the Fast Cat pontoon about 400yd's away!!

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El Alce

 

[jfm]

Fairline do it with all their new boats AFAIK. Right next to the factory, there is a test tank, 100 feet long or so. All the new boats are dunked in there for a few minutes, and engines started etc. Picture here, the building to the right is the squadron 62 building shed

 

[Moose]

Ohhh, my boats been in there/forums/images/icons/smile.gif

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L' Moose

 

[hlb]

But Princess dunk them in Plymouth Sound and give them a proper thrashing.

<hr width=100% size=1> <font color=blue>No one can force me to come here.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[jfm]

I suggest work out the force on the cleats. Depends on throttle setting, but assuming WOT then the maths is

A. you have 330hp
B. convert that power to watts
C. Assume your boat does 20kts in open water WOT
D. Convert 20kts to metres/second
E. Divide power (B) by speed (D) to get force in Newtons
F. Convert Newtons to tons or pounds or whatever, and that is the force on the cleats

Slightly rough calc, but broadly correct imho


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[lanason]

So's mine ??

<hr width=100% size=1>Adrian
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[Moose]

Pity, mine didn't come out of the shed on the right/forums/images/icons/smile.gif

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L' Moose

 

[jfm]

camera pans right.....

Here is that shed on the right......

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[Moose]

Re: camera pans right.....

Yep, that's my new one. Looks good doesn't it? Off for the first sea trial in 2 weeks.


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L' Moose