NMPG Claims vs Real Life

[scoobert]

Originally Posted by Pblais

The bulkheads in a serious hole won't buy more than literally a few seconds assuming you close them in literally a few seconds. A one foot diameter hole is less than that. A small hole you go to shore and the pumps buy some time after that you abandon ship.

All your skills are Ok for most of the finish work but that is the cheap stuff in any case and you could do a crappy job and not be in trouble and perform well. The materials and equipment you need is the real money. All the sail hardware is probably more than $50K plus the deck hardware depending on if the mast is suitable.

You can't really use shore materials on a boat. Boat wiring may use wire but that is about where your shore experience will end. Many of the other items don't work either so you need specialized materials and they all have special procedures that you could learn with practice. Practice on your own boat does not come cheap either. You need to redo things or suffer later.

You can find a lot of history here on CF from folks that did major refits and information you need to do a lot of things so I wouldn't say you can't but I will say it does cost a lot more money than you think. I also know there are a lot of easy way to do things that don't really work. You'll figure out the easy ways before you figure out the right way.

With an older boat you could refit as you go but with this one it goes no place until you are almost done. Most of the earl stuff is better done on land too.

do you think a strike with a steel hull would open up a large fissure? i was assuming it may tear at most.

[shorebird]

A quick look at the photos of the steel boat, and I would place its value at around minus $25,000. To put it another way, you would need to spend about $25,000 to bring it up to a point of being worthless. I just spent $3500 just painting the bottom of my boat, (saved $$$ by doing all the work myself.) and having 3 through-hulls replaced, and stuffing box repacked. The engine in that thing is a joke. If you stripped that hull to bare steel, and repainted it, you would have spent about 5-10 Gs, about 2-300 hours of work, and you would have, maybe, a hull...about 15% of the value of a finished boat. If you really are handy, and want to take on a project boat, there are some good ones around... but try and find one which at least has value on the positive side of zero. Just my humble opinions.

[David_Old_Jersey]

That yacht hull is a whole world of hurt - run. run and hide. and change name and telephone number.......

If thinking of running a planing hull and engines(s) at displacement speeds then gonna discover that they are not designed to do that. Boat will handle like a pig, especially in a sea and engines won't like being run slowly either. Just gonna be buying a world of dissapointment at best.

[scoobert]

the latest yacht i am making an offer on...
i am still ok with my original two boat plan.
this would just be a loop boat.

[scoobert]

Originally Posted by deckofficer

Here is a rough rule of thumb for displacement hulls. If you double the speed, it will take 8 times the hp. If you start with a very efficient hull like the Aspen C90 that is capable of 20 kt on just 150 hp, then 8 kt only requires about 10 hp. Fuel consumption follows work done.

so using your formula, and i doubt it is linear, if the boat i am looking at does 20KTS on 550HP 10KTS should take 70HP, and 5kts should take 9hp?
i dont see how that would be the case.

[boatpoker]

Originally Posted by bdbcat

scoobert....

If efficiency is your goal, drop the word "planing" from your search string.
A 45' displacement trawler will have no difficulty achieving 2-3 NMPG at 6-7 kts.

Dave

No need to drop the word "planing". My Trendsetter 40' greatly exceeds the numbers shown in your post

[scoobert]

lol i was looking at your ad not 10 min ago, thinking how tiny it is. wow thats small.
nice for two people, not for a family.

[deckofficer]

Originally Posted by scoobert

so using your formula, and i doubt it is linear, if the boat i am looking at does 20KTS on 550HP 10KTS should take 70HP, and 5kts should take 9hp?
i dont see how that would be the case.

And why not?

[valhalla360]

Originally Posted by scoobert

so using your formula, and i doubt it is linear, if the boat i am looking at does 20KTS on 550HP 10KTS should take 70HP, and 5kts should take 9hp?
i dont see how that would be the case.

Our 34' has 25hp. We only need about 1/4 to 1/3 throttle to do 5kts. That's likely somewhere around 6-8hp (not sure exact hp to throttle settings). So, yes, 9hp is probably correct at least in terms of magnitude of HP.

Ideally, you don't want to go massively oversized on your engines. A pair of 400hp diesels that never take the boat above 5kts, will cost a lot to buy, a lot to maintain, they won't be as efficent as an appropriately sized engine and they won't like idling long term.

On the other hand, a 9hp engine is probably too small. While it will likely maintain 5kts in calm conditions, with a head wind or punching thru waves, it will likely have trouble maintaining 5kts. Also in docking situations, it may not give you enough of a burst of power to make some manuvers. While I don't like the option, if you will use the engine to power a big alternator, that can eat up a few HP also.

Looking at displacement sailboats and trawlers in the 30-40' range, you typically see HP in the 25-150hp range with assumed cruising speeds of 6-9kts depending on power and hull shape.