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Old 28-01-2020, 19:10   #31
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Re: Repowering a bristol 40

I've done some engine swaps and I'd want to work backwards on this problem. First look at the propeller aperture cutout at the rudder to see how big a prop she can swing as this determines what power and gear ratio is practicable . No point in looking at engines with more power/shaft torque than you can be absorbed. For low drag I'd want a fixed 2-blade (to align with the deadwood) or a feathering prop 2 or 3-blade. Also a factor is what dia. propshaft she is set up for.
Diesels are much taller than the Atomic engine so hopefully it previously had a 40hp diesel. Avoid altering the GRP engine beds in a major way if they are good and strong; engine mount spacing is key though it is feasible to increase an engine's spacing. I did that to a Yanmar 2GM20F to match 18" .
The shaft offset of the transmission matters a great deal. Some ~40hp Perkins for example had 0" offset (shaft inline with the crankshaft like the Atomic 4) and a 'manual' shifting transmission (Paragon) rather than a hydraulic or mechanical/servo operated design. The Westerbeke website is a trove of information on these designs if by chance it was a Perkins engine as they used back in the 60's-70's. With all the expense and work you should consider the value of the end result. She would probably like to have 36hp or more. If a temporary OB engine is needed while seeking the right engine, I'd consider mounting it at the quarter for this boat.
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Old 28-01-2020, 21:11   #32
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Re: Repowering a bristol 40

Originally Posted by TrentePieds View Post

You said: "The seller is prepared to reduce the price to $6,000 if anyone's interested. It's beyond my budget."

Does that mean that a $6K boat plus a $20K engine replacement is beyond your budget?

If so,

1) I salute you for knowing your limits,


2) I warn you that here in the Salish Sea (Puget Sound in Washington State and Straits of Georgia In British Columbia) the ANNUAL upkeep of 40 footer will be a minimum of $12K. I should think it would be as much in the Chesapeake!

Most people can find the money to BUY a boat, far more than can find the money to KEEP a boat.

This is really good advice!
But I want to comment on outboards. My tip is it depends on your usage.
If you want to go on daysails with a reliable weather forecast out from yr storage place be it marina , mooring they can be fine. However if you want good battery charging & expect to be caught out in storms they are a no no.
Reason is yr transom can get submerged. Ask me how I know
Think about yr usage.
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Old 29-01-2020, 09:29   #33

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Re: Repowering a bristol 40

A true story:

More than half a century ago I kept a little Seabird, the Day/Mower design from another half century before that, on the hook in a lovely little cove called Whitecliff Cove near Vancouver. She had an outboard - having been "modernized". It was a British Seagull, Vancouver being then still a far outpost of the Empah.

The seas from the Straits of Georgia were rolling straight into the mouth of the cove. I cranked up the beast which was done with a bit of string around the flywheel. A sea rolled in. The bows rode over it beautifully. The transom dipped, and the engine quit as the water reached the exposed sparking plug. I wound the string around the flywheel again, and she started right up. A sea rolled in. The bows rode over it beautifully. The transom dipped, and the engine quit again as the water reached the exposed sparking plug. I wound the string around the flywheel once more, and she started right up. A sea rolled in. The bows rode over it beautifully. The transom dipped and the engine quit for the third time as the water reached the exposed sparking plug.

I was kneeling there on the poop deck, and as I prepared to wind the string around the flywheel AGAIN, my ire rising, I read embossed on the flywheel: "THE BEST OUTBOARD FOR THE WORLD"

Up went the canvas and out of the cove we sailed. The best outboard for the world is probably still at the bottom of Whitecliff Cove whither I consigned it :-)!

If you have a good boat, don't "mickey mouse" it with an outboard :-)!

On a more serious note: Your CASH (or "near cash") holdings the day before you make an offer for a boat should consist of 1) the actual acquisition costs of the boat, taxes in, plus 2) the first year's operating and maintenance budget, plus 3) a precautionary balance equivalent to the cost of an engine replacement.

As time goes on, you should transfer into the Boat Account each month a twelfth part of the ANTICIPATED annual costs of ownership (the budgeted cost of keeping the boat, which should include an amount for replacement of sails and of the engine). Any amount in the Boat Account that isn't expended in the first year of ownership simply carries forward on your personal Statement of Financial Position until needed, or until you sell the boat, close the Boat Account and recover the balance in it for other purposes.

IMO, if you cannot afford so to arrange your affairs, you are not yet ready to be a boat owner.


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Old 03-02-2020, 07:38   #34
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Re: Repowering a bristol 40

I have a refrigerant engine modified for a marine application. They are 50 -60 HP diesels that are used to keep items in trucks cold or frozen. They are behind the nacelle on the forward end of the trailer above the truck cab. There are millions of them in service and not too much to buy. You need a transmission , and likely water jackets on the exhaust manifolds. Mine is near 50 years old and still runs great, Spare parts are cheap as well and they are durable. The blocks ae all the same and different engine MFGs put them together. Kubota, Mercedes, Isuzu are a few. I have an Isuzu C-221 and it powers an Acapulco 40 sailboat.

A lot to consider, but they work well. When I needed a new water pump, I found it at ThermoKing for less than 100 bucks. One of the people working there said that these engines are rebuilt after 30K hours of service.

Just because you never heard of it does not mean it is not good solution.

Good luck
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Old 03-02-2020, 09:39   #35
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Re: Repowering a bristol 40

Originally Posted by boat_alexandra View Post
sounds like a nice boat, would be a shame to spoil it with an engine.
I'd ignore this poster's ill-advised suggestion.
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Old 03-02-2020, 16:45   #36
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Re: Repowering a bristol 40

I've been playing musical engines with my boat. The original Westerbeke was replaced with a rebuilt Perkins/Westerbeke by the owner after he and his wife sailed around the world. A friend of mine repowered his B40 and gave me the Westerbeke that came out of his boat - and I put it into mine - replacing the rebuilt one. I now have the rebuilt Perkins/Westerbeke in my basement. I put the two alternators from the engine my friend gave me onto rebuilt Perkins/Westerbeke when I replaced them with a new higher-amp alternator (confused yet?).

I've had the rebuilt Perkins/Westerbeke checked by both Bay Shore Marine at Bert Jabin's and at Transatlantic Diesel in Hayes, VA. Both say that the rebuilt engine runs fine - but I haven't had the two alternators checked since I swapped them (although they worked fine on my friend's Westerbeke before I swapped them).

If you would consider a rebuilt engine (Perkins/Westerbeke with two alternators) instead of a new one - contact me and we can get together to see if it works. It pushed my boat around OK, and my boat weighs a bit more than yours. I could let my "spare" engine go for a reasonable price. I also have the engine mounts for it as well as a ZF transmission. I'm not in the Annapolis area - but I can get there fairly easily. I'll be moving my boat to Galesville in the spring.

Love Bristols - beautiful boats. I looked at a Bristol 40 for sale at the Hartge yard in Galesville before I bought my boat.
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Old 04-02-2020, 10:43   #37
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Re: Repowering a bristol 40

Originally Posted by brendanwalls View Post
How much would an electric motor be?

I'm not good enough of a sailor to have a boat this size without an engine in the Chesapeake with its narrow channels and ubiquitous shoals.

To go electric, you need a motor, controller, and batteries, in addition to a lot of very big cabling and some sort of user interface. DIY you could do it for about $3000 or a bit more. A turnkey setup would cost probably about $8k not including batteries. Keep in mind that there are some serious range and speed tradeoffs. I am talking about a 48v system using a 10kw motor, sort of marginal for a 40'er, and a 10kw/hour bank of golf cart batteries. This is a setup that would be more commonly found on something under 35'. Ideally you would want the sort of motor and controller found in electric cars. I would go at least 96 volts for a boat that size. A 21kw/hour bank would give you a decent range with a single series bank. Most e-boaters with boats in that size range go with Lithium either LiIon or LiFePO4. I don't like them which is why I mention golf cart batteries, GC2 flooded cell. If you will just be day sailing, electric is very nice indeed, especially if you do not need any serious range under power. For cruising the advantages fade a lot and those of diesel start to look a lot better.

Honestly I think, partly because of your unfamiliarity with EP and partly just out of general practicability, that you are better off with diesel, and I would give a hard look at a new Beta marinized Kubota. These have a wide user base so plenty of peer support. Factory support isn't bad. The company will ship the engine to a yard or to you, whichever. There is no requirement that an authorized mechanic do the install. What they said... budget around $20k. It does help a little that the old engine is gone. Take this opportunity to detail clean the engine compartment and bilges. Check your fuel tanks if they are metal. It sucks with boats of a certain age to find out too late that an aluminum tank has been sitting on a galvanized screw head for the last 40 years the hard way. Old hoses? Including stuffing box hose? Replace. Replace. Replace.

One more nice thing about the Beta. All the service points are easily accessible. Oil change and other routine maintenance is nice and easy. And you pay farmer prices for most parts instead of yacht prices.

Some of the Beta engines are set up specifically to be direct drop in replacement for the Atomic 4. Just sayin.

Me, I don't want gasoline on a boat. But if you are okay with it and familiar with the safety precautions, a new block A4 is pretty economical to install, just not quite as economical to run as a diesel.

I would recommend against relying on an outboard for primary mechanical propulsion, though a 9.9 could maybe make for decent backup power. The problems are many. First it has to be mounted low enough to have the foot well down in the water, and angled for proper trim. Second, you have to be able to steer it. Okay yeah, you can use your rudder and just lock down the outboard at dead center, but being able to steer the outboard really improves your dockside maneuverability. Very likely you would need a cable steering system or a hydraulic system connected to your wheel. The outboard tiller will be very awkward to reach if not impossible. You will need a strong backing plate and shoring for the mount, to resist the twisting force of the outboard. Outboards are useless when swamped by seawater. You will have gasoline onboard. On a 25' boat it is more realistic. On your 40, it doesn't sound so good to me. The new 4 stroke outboards are very reliable but not as reliable as a well maintained diesel.
1979 Bruce Roberts Offshore 44, BRUTE FORCE
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Old 04-02-2020, 12:15   #38
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Re: Repowering a bristol 40

I looked at that boat. Really tempting! It needs more than a motor though. The topside paint is pretty banged up. The starboard side is pretty baked from the sun (boat hasn't moved since 2016). The interior looks pretty good.

Bayshore quoted me approximately $8k to install a used Perkins 108 (not including the motor). They still have the Perkins 108 and transmission that came out of her. I was told that the motor isn't even worth using as a parts motor.

I found a few rebuilt motors in the annapolis area ranging from $2500 -$4000.

It looks like one of the bolts for the motor mounts was sheared off at some point. That might make things a little more difficult.

Good Luck
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Old 05-02-2020, 04:56   #39
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Re: Repowering a bristol 40

I assume this will be typical for a underpriced project boat. These are a good deal if you are handy and have lots of time to spend (likely 100s of hours) and value your time at $0 per hour.

Otherwise you are better off working those hours at a well paying job, saving up, and buying a well maintained used boat
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