Westerly Griffon Engine Upgrade from Bukh DV20

[hallberg36]

I am planning to upgrade the engine ( Bukh DV20 ) in my Griffon when she is hauled for annual maintenance next month. As a fan of Kubota based engines I'm favouring either a Nanni 3.21 or Beta 25 at the moment, with the Nanni being the front runner due to my having fitted this brand in a previous boat and been impressed by the results. I'm interested if others on this forum have carried out similar upgrades, have any recommendations/suggestions, particularly regarding engine bed modifications and differences in exhaust and water inlet size differences. I'll probably change the prop from the current fixed, 2 blade to a 3 blade, but again am interested if it's worth going for a folding type, which of course a greater cost?

 

[Andrew_Trayfoot]

I have a Beta 20 in my Griffon with a 3 bladed prop.
25 sounds a bit much to me as the 20 is fine.
The big plus for the Beta is that all the service items, except the air filter, are around the front of the engine.



PM me if you want to talk it through.

 

[hallberg36]

I have a Beta 20 in my Griffon with a 3 bladed prop.
25 sounds a bit much to me as the 20 is fine.
The big plus for the Beta is that all the service items, except the air filter, are around the front of the engine.



PM me if you want to talk it through.

Hi Andrew, Thanks for your reply & can you advise if there was much alteration necessary to the engine beds & shaft etc.. As you'll be aware the Beta/Nanni are much smaller, lighter engines so probably a longer shaft will be needed? Also, the size of your prop, and whether it's fixed or folding is of interest. Thanks

 

[Tranona]

You don't need any more than a 20hp. A quick calculation shows that a 16hp will comfortably exceed hull speed at 6.8 knots and a 20 7.21 knots. no point in fitting a bigger engine as you simply cannot use the extra power. When your boat was new, the standard was 10 and the option 20, not because it needed it but because the 10 was marginal and there was nothing available between the two. I have just re-engined a boat with almost twice the displacement of yours with a Beta 30 and that still comfortably exceeds hull speed.

As to the choice between beta and Nanni, I had a Nanni last time but this time I had difficulty here in Poole finding a dealer/fitter interested in the job so went for a Beta. Very happy so far.

Regarding propellers it really depends on how you use the boat, how long you are going to keep it and the size of your budget. The ideal from a motoring point of view is the largest 3 blade prop you can fit and if you have enough clearance a 15" 3 blade would be best which will need a 2.65:1 reduction. However a lot of drag, so really only sensible to fit a feathering propeller at roughly £2k. However as you have more than enough power with a 20 you really don't need a 3 blade and a 13" 2 blade with2:1 reduction would be fine. Probably best compromise would be a 2 blade folding FlexoFold which is half the price of a Feathering prop. Suggest you talk to Darglow Engineering as they sell both types.

If you are near Poole recommend Mike Wills to fit it. Beta have brackets to lnk to your beda. You can probably retain the shaft, but in my experience you need to go through all the installation items (exhaust, fuel supply, water, stuffing box and probably change them all.

Hope this helps.

 

[earlybird]

My experience of Beta is first class in terms of factory advice and support.

 

[hallberg36]

You don't need any more than a 20hp. A quick calculation shows that a 16hp will comfortably exceed hull speed at 6.8 knots and a 20 7.21 knots. no point in fitting a bigger engine as you simply cannot use the extra power. When your boat was new, the standard was 10 and the option 20, not because it needed it but because the 10 was marginal and there was nothing available between the two. I have just re-engined a boat with almost twice the displacement of yours with a Beta 30 and that still comfortably exceeds hull speed.

As to the choice between beta and Nanni, I had a Nanni last time but this time I had difficulty here in Poole finding a dealer/fitter interested in the job so went for a Beta. Very happy so far.

Regarding propellers it really depends on how you use the boat, how long you are going to keep it and the size of your budget. The ideal from a motoring point of view is the largest 3 blade prop you can fit and if you have enough clearance a 15" 3 blade would be best which will need a 2.65:1 reduction. However a lot of drag, so really only sensible to fit a feathering propeller at roughly £2k. However as you have more than enough power with a 20 you really don't need a 3 blade and a 13" 2 blade with2:1 reduction would be fine. Probably best compromise would be a 2 blade folding FlexoFold which is half the price of a Feathering prop. Suggest you talk to Darglow Engineering as they sell both types.

If you are near Poole recommend Mike Wills to fit it. Beta have brackets to lnk to your beda. You can probably retain the shaft, but in my experience you need to go through all the installation items (exhaust, fuel supply, water, stuffing box and probably change them all.

Hope this helps.

Really useful information.... thanks to all who have taken the time to respond, much appreciated. Comments have confirmed most of my own thoughts on the matter. I will probably go for a Nanni 3.21 & a Flexofold 2 blade folding as I digested a fairly recent ( Yachting Monthly? ) review of many different props and the Flexofold came out well.... whether 2 or 3 blade. The Nanni comes with a higher rated alternator as standard and as I've fitted that brand on a previous boat that probably edges it for me.... especially bearing in mind Tranona's useful comments

 

[Tranona]

A 2 blade Flexofold will be fine. Take Darglows advice on size as they have so much experience. I had one on my last boat and they got the size spot on. Same with the Featherstream that I have now. Good luck with the project. You should get a good price for your Bukh as there is always a demand for engines that are worth reconditioning even if they lack the refinement of more modern engines. Unless you get a trade in deal from your supplier best to try and sell it while it is still running in the boat (if it is!)

 

[Andrew_Trayfoot]

Beta do engine mounting kits that are straight swap outs for most of the popular 1970's and 80's engines.

when I got mine I looked at all the Kabuta derived engines at the Boat Show and the Beta stood out head and shoulders above the others in terms of ease of servicing in a confind space.

The other thing I would recommend (which I did a couple of years ago) was resite the primary fuel filter on the port and forward of the engine. It is much easer to servive there than with your left hand from the quarter birth behind the engine.

 

[hallberg36]

Beta do engine mounting kits that are straight swap outs for most of the popular 1970's and 80's engines.

when I got mine I looked at all the Kabuta derived engines at the Boat Show and the Beta stood out head and shoulders above the others in terms of ease of servicing in a confind space.

The other thing I would recommend (which I did a couple of years ago) was resite the primary fuel filter on the port and forward of the engine. It is much easer to servive there than with your left hand from the quarter birth behind the engine.View attachment 155283

Excellent advice.... it's a real drama servicing the primary fuel filter in the original location as fitted by Westerly, accessed through the panel in the portside quarter berth Especially as my filter has the additional glass bowl " Lucas " type with multiple seals.... these are always a " juggling act " getting them to seal so the easier access would be very welcome. Bearing in mind that the ( preferred ) Nanni 3.21 engine has different locations & sizes for exhaust outlets etc.. there is a lot of modification that will be required. The Nanni has a 40mm exhaust outlet ( Bukh 45mm? ) and the inlet water hose on the Bukh is, I think half-inch, whereas the Nanni will require 19/20mm ( 3/4") ....I need to confirm all this when next onboard. As the replacement engine is also quite a bit shorter o/all ( & lighter) I'm curious as to whether to mount it further aft and free up space in front, or keep it pretty much the same as the Bukh and go for a longer, replacement shaft. I'll probably fit an R&D type flexible coupling as well so that will make up a small bit of the difference in length? I'll also try and squeeze in a calorifier if possible and go for the real " luxury liner " experience with hot, pressurized water. This will require refitting a small, sliding sink in the heads as the previous owner had the good grace to remove the original and was into frightening others anchored nearby while taking cold cockpit showers.... he was obviously more " Viking " than myself.

 

[Tranona]

The shaft is the fixed point- or rather the angle so work forward from that. Useful to draw it out full size using the dimensions from the technical details in the Nanni spec.. The sort of constraints you hit with the shorter engines are particularly around the exhaust and the downside of the Nanni is that the exhaust elbow is a casting and I think the high rise is a separate item if you need it. That is a big advantage with the Beta as the exhaust is a stainless steel fabrication so there is flexibility to custom make it to fit. This was very helpful for mine because it enabled us to move the engine back quite considerably. Of course may not be an issue for you. The photos below show before and after and you can see the difference - but again if you cannot use the extra space by reducing the size of the engine box then lot to be said for having the engine as far forward as possible. Exhaust diameters are not a problem depending on what sort of waterlock you have as you can either replace the inlet spigot with some designs or use a reducer.

For the flexible coupling the trend now is to use a Centaflex as you need a complete coupling to mate the shaft to the TMC gearbox flange. Check carefully whether your shaft is 25mm or 1" as Westerly used both. Really important for your new prop as they also tended to put an imperial taper on a metric shaft. If you are having a new shaft stick to the same diameter unless you are changing the cutless and shaft seal. They must all be the same. I changed from 1 1/4" to 30mm primarily because the coupling I used was not available in Imperial and i was changing the seal and cutless anyway. while you are changing the water inlet you might want to relocate it and use a Vetus style strainer mounted immediately above the inlet. You can see that in my photo.

 

[oldmanofthehills]

Really useful information.... thanks to all who have taken the time to respond, much appreciated. Comments have confirmed most of my own thoughts on the matter. I will probably go for a Nanni 3.21 & a Flexofold 2 blade folding as I digested a fairly recent ( Yachting Monthly? ) review of many different props and the Flexofold came out well.... whether 2 or 3 blade. The Nanni comes with a higher rated alternator as standard and as I've fitted that brand on a previous boat that probably edges it for me.... especially bearing in mind Tranona's useful comments

Tranona is correct as ever on hull speed. Where extra grunt comes in useful is banging against a head sea so we go for 25hp for blunt bowed 27ft, however 20hp fine for your boat. Having got rid of noisy thirsty bukh 20, we are in love with our Beta 25 with the bigger alternator

 

[Andrew_Trayfoot]

If you are in the Poole area you are very welcome to come and have a look at my instalation.

 

[hallberg36]

Thanks again to all.... great to get useful and constructive advice from those replying. I'm in Portsmouth so getting to Poole is a bit of a trek Andrew, but kind of you to offer .... Thanks

 

[dunedin]

Thanks again to all.... great to get useful and constructive advice from those replying. I'm in Portsmouth so getting to Poole is a bit of a trek Andrew, but kind of you to offer .... Thanks

Wow. Incredible. Portsmouth to Poole is a nice day sail or, according to Google, a 1 hour drive. So practically on your doorstep.
(Like most others on here, I suspect, getting to my own boat is much further - and just driven 75 miles to get there since reading this post.)
That 2 hours driving could save a couple of weeks of wasted time and effort.

I did wonder of the OP is a bit naive about this in the first post - hoping to do the engine upgrade “next month” when out for annual maintenance, and still debating make of engine. Are these sorts of things now available off the shelf like that? Seem to remember Tranona had quite a wait to get delivery of his new engine? Perhaps planning for a next winter job might be better?

 

[Tranona]

Yes, April to August for delivery and finally launched late September. Obviously biased, but I would be tempted to go the same route as I did and keep the boat in the water while organising the engine and ordering all the bits and lift out when everything is there. Gives an opportunity to advertise and sell the existing engine while it is still working (if it is!). Mine was of course a bit more complicated with more mods to do and summer holidays slowing down both delivery of engine and machining. However paid off as just 2 weeks before the engine was due I sold the old one. First phone call on a Monday, bit of toing and froing with dimensions, specs etc plus making a video of start and running. LIfted engine out Friday morning after receiving a small deposit by transfer, collected and paid for in the afternoon.

 

[alahol2]

There's a description here of the kind of things that need to be looked at when you re-engine...

 

[Tranona]

Brings back happy memories. Interesting he went for the 14 rather than the larger capacity 16 which would have exceeded hull speed by a bit. This vicprop.com/displacement_size_new.php will do the calculations for you and work out suggested propeller for your chosen engine/reduction ratio. I used it to assess all the different combinations available with different engines/boxes.

 

[alahol2]

Brings back happy memories. Interesting he went for the 14 rather than the larger capacity 16 which would have exceeded hull speed by a bit.

I think at the time (2005) the 16 wasn't an option. As it happens there are very few times when the extra power would have been appreciated. Engine still running happily.

 

[hallberg36]

Wow. Incredible. Portsmouth to Poole is a nice day sail or, according to Google, a 1 hour drive. So practically on your doorstep.
(Like most others on here, I suspect, getting to my own boat is much further - and just driven 75 miles to get there since reading this post.)
That 2 hours driving could save a couple of weeks of wasted time and effort.

I did wonder of the OP is a bit naive about this in the first post - hoping to do the engine upgrade “next month” when out for annual maintenance, and still debating make of engine. Are these sorts of things now available off the shelf like that? Seem to remember Tranona had quite a wait to get delivery of his new engine? Perhaps planning for a next winter job might be better?

I've been accused of many things with regard to sailing & boats, but naivety is not one of them. With over 40 years of both sailing and engineering in a variety of boats, including fitting a new engine in my last boat, My objective here was to take the time to draw on the wealth of experience available on this portal. Learning from personal knowledge and experience gleaned from choices made is, in my humble experience, a worthwhile exercise. Indeed, the ( mostly ) constructive comments received do, in my mind prove the point. For what it is worth, I had already checked that both the Nanni, and the Beta ( always the 2 front runners ) are both readily available ( ex-stock ) from the Nanni importer, and local Beta Agent, for delivery when the boat is hauled out next month. Preparatory work can be done in the meantime. The prop and shaft are on a 2 week lead time ( if necessary and deemed necessary?), and other items, exhaust etc.. are available next day from ASAP, and others. Hope this clarifies matters for those with doubts.

 

[Tranona]

Yes, delivery has eased up recently. I was talking to the Beta agent yesterday who was fitting a 20 into a Centaur and that was ex stock. However last year when I went through this exercise availability was appalling of all makes. A combination of Brexit, Covid and material shortages. Right into the autumn the Beta 25 was not available for example. I just hit a bad year as when I started my project search in mid 2021 I was being offered discounts on some brands and immediate delivery. By the time I bought the boat in November 2021 and started seriously shopping all that had changed, and prices had gone up by around £1000 for a 30hp. Only bright spot was that I managed to sell the old Perkins/Volvo for a really good price while it was still running in the boat.

Hope your project goes OK.