Hi all.

I’ve got hold of a 1976 26 family with no engines. Original it had twin 130 hp installation.

Thinking of putting two aqad41a’s in it. About 200hp each. Not because I really need all that power, but because I have those engines available.

But one thing concerns me: the thing I like with coronet is it’s hulls, deep V and capability of great handling in speed and rough seas (at least with the 24” models in my experience). But when I look at the 26 family hull, it doesn’t really look like a coronet. It has more of a displacement hull in my opinion, with a small keel and almost flat stern.

So my question is: is this boat even capable of running 40+ knots? With 400hp it should be able to if the hull was built for speed. How’s it’s handling, especially in rough seas?

Thanks for all thoughts

Juan

Take into consideration that AQ130 with sterndrive is about 200kg each, AD41 about 550kg each. You will add about 700kg in the stern, more than twice the previous installation.

My tip is to forget the dual installation and these old engines even though they are quite reliable parts are expensive and the upkeep of two engines and sterndrives.

Have the transom rebuilt since it probably need it anyway and install one new modern VP V6 220 or similar, engine is in SE about 25k USD, or if you'd really like to use the engines you have, install just one of them. 200hp is ok for that size of hull.

I have a Nimbus 26 DC, about 2800kg, AD41p and with full throttle i reach about 32knots with props adjusted for torque rather than speed.

Just my personal thoughts

You have to decide at what speed and what sea You'd like to use. The fact that the hull is flat is not likely to cause problem i heavy sea, the open afterdeck and large windscreen are more likely to pose problems. This has been discussed in this forum last year. One Engineering is much cheaper to installera, service, maintain etc. Extra safety with twin engines? Well, yes, provided You service them accordingly, but, at half the cost You can service one engine perfectly. If Your priority is 40 knot, don't consider this boat.

Hi Juan

There are 4 testreports in the archive on 26 family. One performed by Volvo Penta and three by Botved Boats. From the VP testreport from 1977 one can see a topspeed of 25 kn fully loaded with 2 persons onboard with a single AQD40A/280B. From the BB testreports one with a twin AQ130/270C from 1974 claiming 25.5 kn @ 2.6 degrees trim. Another from 1975 with a single AQ170/280C claiming 22.1 kn @ 3 degrees trim. A third also from 1975 with twin AQ140/280D claiming 29.1 kn @ 2 degrees trim.

A few conclusions can be drawn from these numbers.
i) as there is no weight difference between AQ130 and AQ140 (~400kg) the 4kn speed increase come from 20 more horses AND the new drive that is more efficient (creates more thrust).
ii) the single AQ170 installation is about 120 kg lighter and have 100 horses less but is only lacking 3 kn in top speed. Again with a better drive
iii) at 29 kn and trim angle of only 2 degrees the boat is very very near an unstable speed zone

Thus my suggestion is:
- find an engine/drive package that weigh no more than 400 kg
- buy the most efficient drive you can find with best thrust. New duoprops deliver 30-40% more thrust than the original drives.
- limit your speed to 30 kn meaning with more efficient drives you get away with less power (and less weight) which translates to better fuel economy
- want to go faster. Use the original 24-foot hull

/per