Simmons 18 Transom/Motor Well

[kartoffel]

I've bitten the bullet and started on a 18' Simmons Sea skiff. I've got a question on the motor well construction.

I plan to use a 25HP Suzuki with remote steering and power tilt, but won't purchase it until the build is complete (or nearly so).

Can anyone tell me if I need to modify the motor well design to get the full turning radius and tilting of the motor? If not any idea how to find it out. I have the brochure for the motor but there is not a lot of info.

Thanks
Jeff

[pipefitter]

You'll get varying opinions on this but mine is of the side that says to leave the motor well alone but instead limit the swing of the motor. For one, The amount that will fully turn in the well will put the small Simmons on it's ear which you will find that you really never need to turn it that sharply. Another is, there is a hook in the Simmons hull that keeps the boat from porpoising acting like built in trim tabs that is on either side of the motor well and the Simmons can really use all of the planing surface it can get. Plus I feel the smaller dog house door in the stern looks nicer as Simmons designed it. There is a way to make clearance in the upper part of the well for the newer motor cowling to clear, without butchering the working part of the hull.

There is another forumite (Erster) that has other options and more experience with the 4 stroke motors and the Simmons hulls in general. Maybe he will chime in.

You can also email Dave Carnell for his take on it as well.

[michigangeorge]

Good photo found thru Jay Greer's thread over in People & Places:
http://www.boatdesign.net/gallery/showphoto.php/photo/12330/ppuser/276

Simple-tilt the sides outward:)

[G. Schollmeier]

In the description for the Sea Skiff in the picture it said the motor well was modified to allow a 25hp.

[pipefitter]

"There is a way to make clearance in the upper part of the well for the newer motor cowling to clear, without butchering the working part of the hull."

The picture shows precisely what I meant. It also helps act as a splash return for what the spray rails in the well let pass on hard turns. There is also other ways to do it if you don't like the ramped sides profile.

[erster]

Well construction and modifications such as the flare out at the top in many cases can be fruitless for what you get in return. The reason for this is where the peetube is located on a specific engine. Side discharges on some brands with the flare to maintain and achieve the full turn can still give you spray up into the boat from the engine discharge. The lower cases of the engines is where you get into the issue of limited space and not really the prop area and shaft. While people have enlarged the wells there are ways to accomplish the turns without changing the width of the wells eliminating some of the bottom.

What I would do is to address the well face angle is to increase the angle by three degrees for use of the four strokes and for down the road upgrades long term for your boat given the evolving technologies. The weight is greater than the two strokes of comparible sizes in hp. [note, thats just my personal opinion]

When you do this the fore and aft distance to the inside transom face is the key measurement you want to address, making sure that you have the clearance, especially if you plan to use a covering board aft too as some people do.

You may need to adjust the foward well bottom frame making sure that you have the clearance. For anyone reading and maybe considering building a Simmons, the minimum for most four strokes is around 18 1/2 inches starting for the 15 hp engines in most all cases.

I probably would not use the 25 hp Suzuki though as they are not really smoothe running engines. I do personally get great service from them but in the larger ones. Also the most recent ones have been built using less than perfect engine blocks unlike the older ones. There are some leftover Yamahas around in that hp and I would look around for one in that hp since they are also priced to sell.


We use an additional peetube added to the discharge at the engine block if its a side discharge engine and divert the water to the aft end of the shaft down a ways securing it with a big tywrap eliminating the additional work to the well in the 18. The boat needs all the bottom aft thats drawn. You can still make the modifications to get the swing but don't look at the modication as a complete fix without addressing the discharge issues.


There are a couple other changes that you can also do which has also been done in some upgrades of the older hulls with long shaft , but going a bit further with the well then some of the folks did when installing a long shaft four stroke engines from the original short shaft well face..

Some folks just raise the well face and you can also do this and then you can let the sides of the well taper downward and use splash guards at the top of the angles shaped like a wedge since the transom edges is where you really need to clearance in the turns.

This shows a typical example without splash guards mounted to the outside face of the side supports. .

http://img.photobucket.com/albums/v356/Bateau1/DSC02197-1.jpg

[spirit]

Look at Wooden Boat Sept/Oct and Nov/Dec 2005, and Jan/Feb 2006, for very detailed step-by-step instructions as to how to build the Simmons 18 Sea Skiff for a 30 HP outboard motor.