[sparrowe]

So here's the question as we get ready for the 2014 sailing season (assuming that this lousy cold weather will break before too long!): How to increase the depth of our outboard propellor? We sail a Beneteau 210 on an inland lake; our motor is a Lehr 5 HP. When the wind is 10 knots or less, and the water is relatively flat, we have no problems motoring in and out of our marina. But when the wind goes up and we get some waves - even modest waves - we hear the prop "ventilating" (i.e., rpms rise) as we go over the crests and the stern of the boat rises. The situation worsens when one of us goes forward to lower and gather the jib as we come in to the marina.

The two pictures below show the location of the prop with the outboard motor bracket at its lowest position (text continues below the pics):

The upper image shows the top of the prop blades clearing the bottom of the hull, this image was taken with the camera at a higher elevation than the waterline of the boat. I think this image fairly reflects the situation when we are motoring in flat water with the (not insubstantial) weight of our bodies in the stern of the boat. The lower image - taken with the camera held at an angle below the waterline of the boat - shows most of the prop being higher than the bottom of the hull. This image is how I imagine the situation to be when cresting over even a modest wave. Although the "cavitation plate" is aligned with the bottom of the boat at the transom, the entire transom is out of the water momentarily.

I can see three options:

1. The existing Garelick mounting bracket has a 11-1/4" vertical travel. I could change that bracket for a similar Garelick bracket with a 14-1/4" vertical travel - and, as far as I can tell, do so without drilling new holes, etc. However, I'm assuming that the extra three inches of travel equates to 1-1/2 inches higher and 1-1/2 inches lower. I'm not sure how much improvement that will buy us for the $200 cost of the new bracket.

2. We could replace our Lehr 20" long shaft with a Tohatsu 25" extra-long shaft outboard. The cost of that option would be the difference between what a new Tohatsu costs (about $1550) and what I could get for a one-year old lightly used Lehr ($1000?). This option clearly would put the prop lower in the water. I'm assuming that even with the extra long shaft I could raise and tilt the prop out of the water when we are in the slip. But I would have to sacrifice the advantages of propane and accept the disadvantages of gasoline. And, might this not be overkill?

3. I could accept that I am overthinking this, and put up with a situation that isn't the best of all possible worlds but, in the context of inland lake sailing, is hardly life threatening. A jib downhaul would be easy to rig and allow us to keep our (fat) butts in the stern of the boat when motoring in to the marina.

So, what's the Sailnet wisdom on these options? Sit tight (do nothing), buy a little improvement (replace the mounting bracket), or go for the big fix (extra long shaft motor)?

Thanks so much!

 

[Faster]

How close is the powerhead to the stern wave surface at speed under power? If there's no risk of submerging the head, maybe you can lower the existing bracket a bit? Keeping in mind the need to tilt it free in the up position.

Going to the longer throw bracket is probably the more cost effective path - you should be able to offset the cost of the new mount somewhat by selling the old one to someone.

 

[sparrowe]

Hi Faster,

Moving the outboard motor bracket lower is another option; my reluctance to go that way is based on two considerations. First - and this may be what you are asking in your question about the height of the powerhead - lowering the bracket means having to tilt the throttle handle up more than now is the case. I could probably work with two inches lower - I'd face that anyway with a new bracket that has 14 - 1/4" inches vertical travel. The second consideration is the one that matters more. Lowering the position of the bracket on the transom means drilling new holes, filling existing holes, and repositioning the backing plate. Given the way the boat is constructed, reaching and working on the interior of the transom appears to require incredible gymnastics. In fact, I'm scratching my head as to how the bracket was installed in the first place - must have been done by trained mice! Unless I'm missing something (the boat is relatively new to us), I think I'd bite the bullet and get the Tohatsu before trying to relocate the bracket.

Thanks!

 

[Minnewaska]

Are you going to have the boat a while? If so, get the right tool for the job. In your case, that would seem to be a motor with a longer shaft.

Btw, your mounting bracket could have been installed to the transom before other parts of the interior cockpit were fitted. If the interior is now inaccessible, its not impossible to fashion a system that secures from the outside. However, I agree that its not your best choice, only less expensive.

 

[hellosailor]

Gobs of cash can solve many things, but can you solve the problem just by outsmarting it?

That is, put all crew aft when you need to run the engine in those conditions. If you need to send a crew forward to drop the jib, do that while you are still in open water and can afford to idle the engine. then come aft and power it up.

Or, get a couple of five gallon water bottles or collapsible bladders. Fill them and tie them outboard of the transom when you need to motor in rough water. Drain them and stow them when you don't need the weight.

There's usually a way to outsmart a boat. If Beneteau doesn't say the boat "needs" an XL shaft engine, ask them how else they outsmart the boat.

 

[Alex W]

A 21' boat should be able to get by with a 20" shaft. 25" is nicer if possible.

Does Lehr makes a 25" shaft version of your outboard? If so will they sell you the hard to convert your engine? That would probably be cheaper than doing the buy and sell.

The bracket was moved (not by me) on my old Catalina 25 by mounting some square channel stainless to the existing mount points, then adding new mount points to the channel where they wanted the bracket to be now. It worked well, but maybe didn't look the best.

You can see a photo of it here (warning, large photo to make the bolts visible, that is why I didn't inline it):
http://alexandchristine.smugmug.com/Sailing/Lutra-April-2012/i-ZWVSM6v/O

If I were buying a new transom bracket I'd also check out Garhauer, they seem to make nicer ones than Garelick at a similar price point.

 

[sparrowe]

Alex, your picture is most helpful - it looks to me that the S/S channel is hardly and eyesore because it is largely hidden behind the motor and bracket. Hellosailor, I'm going to keep your ideas for 'outsmarting' the boat in mind for other problems. Minnewaska, your observation makes lots of sense because it reflects the way I prefer to approach boat ownership - adopt the best solution. I'm thinking now I'll just bite the bullet and get the new motor - not only is it likely to completely solve the problem, it's an easy fix: hang the new motor on the boat and go sailing. Yes, more expensive - but not too much more than an new bracket. Yes, I'll have to go through the hassle of selling the Lehr, but I can schedule that around sailing days.

Thanks, all!

 

[PaulinVictoria]

I had the same issue on my previous boat, I bought a complete used long leg and swapped it over, took about ten minutes. I of course had the advantage of having a mainstream motor with tons and tons of spares available (Honda).