Congratulations on your boat! My three boats, (all self built), were a wharram
23, a Seaclipper 28, and our current Searunner
34. The first two had outboards on a swinging bracket, the third has an inboard diesel
. Some thoughts I could pass along, are ...
With a 68 HP engine
and properly functioning saildrive
, your boat should almost be a motorsailor! IF the hull
and prop are clean... either the prop is WAY WAY too small, or SO much too large that the engine
can't revv up, or the engine needs work and can't reach Max RPM
. Every engine's manufacturer gives you a Max "cruising" RPM
, and a Max "MOMENTARY" RPM. Your prop should be such that the engine just can
reach max RPM, but it should be large enough that it is a strain for the engine to do so. Then run it at its "sweet spot" = (something maybe 10% below the MAX cruising PRM), where fuel consumption
per mile, engine vibration, oil consumption
, etc.. all seem happy. So fix the problem with your current
engine, seems like the first, easiest option. (This is what I would do).
If you do, you accept that it will handle like a barge in very tight marina basins. In that case, call ahead, and always seek outside dockage. This is what I have done with our current Searunner
, as it has a very large turning radius, (except in "0" wind
or current), when I can make her spin in place, by fwd. / back / fwd. etc...
It would still be a great sea boat if you do the above. Also, a diesel has more reliability
and longevity X 3, over ANY outboard
you get your speed problem fixed, and you REALLY want tight quarter maneuverability, you could add a small bow thruster in one of the bows. That is relatively cheep and easy to do, but adds regular "fouling removal" maintenance
. This would be cheaper than reworking the entire propulsion
Also, if you really want that maneuverability, and are willing to spend the bucks, you could put a saildrive
in each hull
, driven hydraulically or electronically, with the on deck
diesel producing the power in both cases. This would work well if done perfectly, but be expensive.
Outboards... If you go this route
, I would definitely put them on hinged "V" shaped nacelle brackets, mounted on the aft cross beam, as close as possible to the insides of the hulls. This would be enough separation. You would want to raise them when sailing. Not just kick up the engines, but raise the brackets. The OB motor
solution might work fine in relatively minor seas, but have a third of the lifespan, and consume several times the fuel! They get a lot of salt
back there, so corrode out before they wear out.
For just entering an inlet near slack conditions, or motoring up a river, OB engines should be OK, but not in any rough conditions. They tend to cavitate badly, so you have to run at half throttle, because if run at high RPM, when the props jump out of the water
or suck air, the engine can instantly rev its mechanical brains out! So, OB motors are not for rough seas or motorsailing in extreme conditions, NOR are they cheap
IF you can live with OB motor's limitations, You may find that a couple of long shaft 10 HP motors designed for that purpose, like my Seaclipper 28's (9.9 Yamaha saildrive), would work best. These engines have huge props geared for pushing a heavy boat at 7 knots, rather than a conventional 30 hp motor
, that has a small prop geared to push a small boat at 25 knots... When empty, my Seaclipper 28 could motor at over 10 knots with one of these! With two of them, your boat might still only be a 5 knot
boat, but you would have solved
the maneuverability issue.
I loved my Wharram
, but one thing about them, is that hard to windward, they side slip. They aren't really going to where they're pointing. I used to just point my bows 10 degrees upwind of where I wanted to go. This is fine crossing oceans, but there are times when motorsailing is a real advantage. One obviously, is in light air, the other is in a gale!
With our current Searunner... When we sailed non stop from Glovers Reef, Belize
, to the Dry Tortugas
, the last two days were in 10' seas, and wind
in the high 30s! We were HARD to windward and really taking a beating. The thing was that it was not yet life threatening, and if we could point a few degrees tighter, we could lay the Tortugas the next day. On our current course, we would miss the Tortugas, and then have to cross the Gulf of Mexico
, landing perhaps in Texas
a week later! Our other option was to tack, and stay in these conditions for 2 or 3 more days. By motorsailing, with the engine at fairly low RPMs, we could point 5 degrees higher! Moral being... There is a lot to be said for a propulsion
system that allows motorsailing in rough seas.
These are the ways you can go, pros and cons. If it was MY Wharram, and I wanted it to be a serious cruiser, sometimes running inlets etc., Rather than OB motors... I think that I would go with option # one or two, and if I REALLY wanted maneuverability, consider either the bow thruster, or twin out drives, powered by the deck
Hope this is of use.