Senior 31 Repower advice

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barryassheton

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Hi, I am currently refurbishing a Senior 31 which has twin AQ171c engines with 290 SP legs. I have just been informed by the mechanic that the engines will be costly to repair. so I am looking into my options. I wanted to fit twin diesels anyway and do away with the petrols but I am not sure on the weight limits of my hull. My current engines weigh about 268Kg each+ legs and I know diesels are heavier. If anyone has any knowledge of the Senior 31 hull which is the base hull for the Project 31, Princess 32, RLM's and a few others. All I know on the weights of the hull was it was rated to 30 people.

Thanks in advance. Baz
 
Couple of kad 42 or 44 would be nice!! There was once a project 31 identical to mine called Cockayne which had 2 vp aqd40a rated at 130 each.. Very nippy.
 
Fair point but both those options are rattley noisey 4 cylinders, better to go bigger and have plenty in reserve, plus the shock factor when passing p50's would be priceless ;)
 
I've just sold a tamd41a. I'd say that the kad 32 would be a good bet.
Many years ago a friend had a princess 43 with 40a 130 in, it was heavy on the stern and would not come up on the plane without trim tabs.
Your 290 drives will have petrol ratio bottom end so you will need the diesel ratio drives as well.
 
I should imagine Ford fsd are the best option in reality, will give a nice 10/12 knots.

Regarding props, I have mixed n matched alsorts but with the rib/motor hanging off the back and all the other junk we carry I can't complain I spose.
 
Thank you for all your suggestions. All the engines mentioned have weights in excess of 400kg and my Aq171's are just below 300kg. When I removed the transom shields I did notice the old water line was around 2" higher than the current one so I dont think the extra weight will be a problem, However would I have to offset the extra weight with ballast in the bow?. I also measured the engine bay and I have about 34" from transom to bulkhead so the KAD42 would be out as it is over this. I am going to contact Lancing Marine today to see what they can offer.

Thanks Baz
 
Maybe a yanmar 240? I take it they're not into the Ford fsdt any more? They would definitely fit?? Or a 4cyl Isuzu td, I have seen both in a rlm before.
 
I know of a P32 that was re engined with KAD32''s and had to have new drives as well.Was DIY'ed but still cost a pretty penny I suspect.She was a flyer but sat very stern heavy.Didn't fetch much more than a well maintained original one when sold.
Lancing marine can't help?
Google marinising transit banana engines.I believe you can squeeze 140hp out of them and they won't cost the earth and parts are cheap.Can be a bit rattly.More insulation could sort that.Friend of mine had two in a Cleopatra on 270 drives.
As solitaire has said transits will fit.As will Peugeot 1.9xld's and lancing used to do vetus 65hp that fitted I believe if you don't want to plane.More knots equals more money!
 
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Hi, Have you considered the FNM range. ATM135 (135hp) is a basic mechanical controlled engine weighing in at 224kg or HPE135 (135hp) is common rail electronic and weighing in at approx. 185kg or if you want more power the HPE205 (200hp) is also common rail electronic and weighs in at 290kg.
FNM also offer kits to couple to VP sterndrives.
Contact Julian at the Mermaid office in Poole if you would be interested.
Best regards
Jon
 
Our mechanic has come up with a couple of packages for engines and drives that don't sound too bad although the price is still high. I my look at maybe a donor boat as suprisingly this seems the cheaper option.

Tico what is the HP on the FSDTi as all I can find on their site are 65HP each, This wouldn't get us on the plane according to manufacture specs. My hull would need 12.5 - 14 Knots to get on the plane and that's with tanks half empty and nothing on board.

Thanks Baz
 
Hi Baz,

Does your Senior have bilge keels? Reason for asking is that definitely with bilge keels, and even just with the regular 4" fin keel, these hulls can get skittish at speed.

We had a Princess 32 with the original 106hp Volvos on 280 drives, and when the bum was clean and fuel was low, we could reach 18 kts. Except once we came off a wave slightly sideways and the fin keel caused us to broach. The rudder effect of the drives was out weighed by the fin. The fin was a poor judge of heading! I was told at the time that the bilge keels were worse still.

There is definitely a law of diminishing returns in putting too much hp into these hulls. Apologies though if teaching granny to suck eggs!

Good luck with your decision

James
 
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